Plain-woven PET fabric with an areal density of 88 g/m² was treated at 100 °C for 60 minutes in an open beaker, then washed, dried and heat-fixed at 210 °C for 15 minutes. The three baths had approximate pH values of 6.5–7.0, 4.5–5.0 and 12.5. Commercially procured Ti3C2Tx with purity above 98% was used. This was a controlled materials experiment, not a clinical study or an assessment of finished consumer products.

Neutral treatment produced relatively large, multilayered MXene features, whereas ascorbic acid yielded the most exfoliated and conformal coating, with an observed sheet thickness of about 8 nm. Alkaline treatment produced smaller flakes but also caused visible pitting in the PET surface. These differences showed that the chemical environment changed more than the interface alone: coating size, stacking, oxidation and substrate morphology also varied among treatments.

Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy showed treatment-dependent changes in PET carboxylates and MXene surface states. The neutral sample retained the largest Ti–C fraction, while the acidic and alkaline samples showed increasing Ti–O and TiO2 contributions, with the alkaline sample showing the lowest Ti–C fraction. The combined findings were consistent with hydrogen bonding, coordination and possible localized Ti–O–C-type interactions, but the authors cautioned that these measurements did not establish a specific covalent bond or its strength.

X-ray diffraction indicated that processing also affected PET structure. Apparent crystallinity was 65.30% for untreated PET, 56.20% after neutral treatment, 39.24% after acidic treatment and 63.47% after alkaline treatment. The acidic condition therefore produced the greatest disruption of the X-ray-detectable ordered PET domains among the three treatments.

Under a 100 W infrared lamp for five minutes, MXene-coated fabrics reached mean surface temperatures of 82 ± 1.2 °C for neutral treatment, 76 ± 1.5 °C for acidic treatment and 81 ± 1.1 °C for alkaline treatment. Calculated photothermal conversion efficiencies were 86%, 77% and 84%, respectively. Thus, the more uniform acidic coating did not produce the highest peak temperature, showing that coating architecture and morphology were relevant to the measured response.

Under infrared irradiation, bacterial inhibition reached 99.2% for E. coli with the acidic-treated fabric and 98.8% for S. aureus with the alkaline-treated fabric. Complete ice melting took 21–22 minutes across the coated fabrics, compared with 30 minutes for untreated PET. Maximum X-band electromagnetic shielding was 21.73 dB for the acidic sample. After 24 hours of ultraviolet exposure, methylene-blue removal reached 98.4% for alkaline-treated fabric, 97.3% for acidic-treated fabric and 96.6% for neutral-treated fabric.

The treated fabrics retained tensile strengths of 301–321 N, equal to 111.5–118.9% of the untreated PET value, while abrasion mass loss remained between 0% and 1% after 20,000 Martindale cycles. However, alkaline exposure caused localized PET degradation, and several reported measurements were single observations. The study also did not establish long-term performance under repeated laundering, ultraviolet exposure, perspiration, deformation or environmental aging.

Overall, the experiments show that pH was an effective processing variable for tailoring Ti3C2Tx-coated PET textiles. The results support a combined effect of interfacial chemistry, MXene oxidation and termination chemistry, coating morphology and PET modification, rather than attributing performance differences to interfacial chemistry alone.

Subject of Research: Effect of pH-programmed hydrothermal treatment on Ti3C2Tx MXene-coated PET textiles

Article Title: pH-tunable interfacial chemistry of Ti 3 C 2 T x MXene on PET textiles for multifunctional performance

Article References: Shahin, S. M. T., & Montazer, M. (2026). pH-tunable interfacial chemistry of Ti3C2Tx MXene on PET textiles for multifunctional performance. Results in Engineering, 32, Article 113513. https://doi.org/10.1016/j.rineng.2026.113513

Image Credits: AI Generated

DOI: 10.1016/j.rineng.2026.113513

Keywords: Ti3C2Tx MXene, PET textile, interfacial chemistry, hydrothermal treatment, photothermal materials, antibacterial textiles, electromagnetic shielding, photocatalysis, deicing, surface functionalization, pH-tunable, interfacial

The authors examined seven published hepatic drug-delivery systems, including liposomes decorated with cyclic RGD, the EGFR-targeting GE11 peptide, the cell-penetrating peptide BR2, a plasmin-binding tripeptide, an anti-GPC3 antibody paired with the CPP44 peptide, and the HBV-derived lipopeptide Myrcludex B. Across this entire set, only one study, Calandro and colleagues’ plasmin-binding tripeptide system, actually quantified conjugation efficiency as a fraction of peptide input. In that case, a nominal four-to-one maleimide-to-peptide ratio yielded just 33 percent conjugation, corresponding to roughly 300 peptide molecules per liposome. In the other six systems, nominal stoichiometry and identity-confirming assays such as MALDI-TOF or SDS-PAGE were used in place of true quantitative yield measurements.

Why does this matter so much? Because the biological claims built on these formulations hinge on ligand density. Du and colleagues reported more than tenfold higher accumulation of cRGD-labeled liposomes in activated hepatic stellate cells, while Lin and colleagues achieved 1.89-fold higher HepG2 uptake and 63.4 percent tumor inhibition with their dual-ligand arsenic trioxide liposomes. Zhang and colleagues found that 0.5 mol percent BR2 gave uptake indistinguishable from unmodified liposomes, whereas 2 mol percent increased uptake significantly. But if the actual number of peptides on each particle is unknown, these density-response relationships cannot be reliably interpreted, and apparent synergy in dual-ligand systems may partly reflect uncharacterized differences in effective density between comparators.

The chemistry itself is individually well understood. Maleimide rings can hydrolyze into non-reactive maleamic acid during aqueous processing, with the extent depending on the formulation and the process conditions. Work by Oswald and colleagues demonstrated the scale of this loss: when maleimide-functionalized lipid was incorporated during liposome formation, only 63 percent of active maleimide survived preparation, falling to 32 percent after dialysis, whereas post-insertion of pre-formed micelles retained 76 percent. In their solvent-injected DMPC and cholesterol system, roughly 37 percent of surface-accessible maleimide functionality was lost during pre-insertion processing, due to lipid orienting inward and rapid initial hydrolysis.

These retention figures, however, cannot simply be transplanted into other studies. The authors stress that Oswald’s measurements come from a specific lipid composition and preparation route, and comparable hydrolysis kinetics have not been established for the other six systems. A peptide-in-excess formulation reported by Du and colleagues, for example, corresponds to roughly one maleimide for every sixteen peptide molecules if calculated on total lipid, yet conjugation efficiency was never measured. In Lin’s dual-ligand system, neither the maleimide-to-antibody ratio nor the coupling efficiency for either ligand was reported, and the published CPP44 sequence lacks the cysteine stated in the Methods section, leaving the source of its reactive thiol unresolved.

The peptide side of the reaction carries its own unmeasured losses. Reduction with TCEP or DTT, or chemical thiolation with reagents like SATA, generates the reactive thiols that peptides need for coupling, but this pool degrades through re-oxidation, incomplete deprotection, disulfide formation, and solubility limits in the reaction buffer. None of the seven systems tracks either active maleimide or reduced peptide thiol over the course of the reaction, so coupling yields cannot be attributed to any specific cause. Reaction pH varied across studies, from Cheng’s pH 7.4 coupling of Myrcludex B to Zhang’s pH 6.5 coupling of BR2, both within the general 6.5 to 7.5 window of maleimide-thiol selectivity, but pH alone cannot explain yields that were never quantified.

To close this gap, Maroof and Genç propose a reactive-site accounting framework that separates six quantities often blurred together in practice: nominal maleimide input as stated in the lipid composition, reactive maleimide as the outward-facing unhydrolyzed fraction actually present at coupling, available peptide thiol as the free-thiol fraction surviving synthesis and handling, conjugation efficiency as the proportion of input peptide that attaches, final conjugated ligand density in molecules per particle, and biologically accessible ligand density as the fraction capable of engaging its receptor in the biological milieu. The framework requires two parallel accounting terms rather than one, because conjugation efficiency is set jointly by whichever reactive pool is limiting under the reaction conditions used.

The proposed workflow is concrete. Before conjugation, researchers should quantify active maleimide using a calibrated thiol-probe assay, incubating a liposome aliquot with a known excess of cysteine or glutathione under the same buffer and temperature conditions used for coupling, then quenching with excess thiol scavenger and measuring residual probe by HPLC or a validated colorimetric or fluorometric assay. In parallel, the accessible peptide-thiol pool should be measured immediately before coupling with Ellman’s reagent or a validated fluorescent probe. Both measurements should be normalized to recovered lipid, determined independently from phosphorus analysis or a validated lipid-specific assay, rather than to nominal input. After purification, residual free peptide, total conjugated peptide, and total recovered lipid should be used to calculate conjugation efficiency and molecules per particle. During biological characterization, biologically accessible ligand density and functional avidity should be determined, along with storage stability and batch-to-batch variation of the conjugation layer.

The authors emphasize that route selection must be evaluated experimentally rather than assumed. Post-insertion of pre-formed DSPE-PEG-maleimide micelles into pre-extruded liposomes better preserves maleimide reactivity than incorporating the maleimide lipid during initial liposome formation, but insertion efficiency depends on liposome size, lipid phase behavior, PEG-lipid structure, temperature, incubation time, and removal of residual micelles. Evidence from outside the hepatic set shows what complete reporting can look like: Gray and colleagues documented conjugation efficiencies consistently above 90 percent across three maleimide densities using a validated fluorescence assay, while Martínez-Jothar and colleagues found that for one peptide ligand a two-to-one maleimide-to-thiol ratio gave 84 percent conjugation, whereas a five-to-one ratio with longer incubation gave only 58 percent, demonstrating that no single ratio can be transferred across ligands and formulations.

The implications reach beyond liver targeting. Hydrolysis, steric crowding, and thiol re-oxidation are inherent to thiol-maleimide chemistry regardless of target tissue, and the seven hepatic systems serve as an illustrative case set for a broader reporting problem in nanocarrier functionalization. The authors caution that their evidence base demonstrates deficiencies in reporting rather than proving maleimide availability to be the primary cause of performance differences. They argue that reactive-site stoichiometry should be treated as a critical formulation variable, reported alongside size, polydispersity, encapsulation efficiency, and zeta potential, consistent with the FDA’s risk-based framework for liposomal drug products. They also call for single-particle methods capable of quantifying particle-to-particle ligand-density distributions and propose a factorial experiment varying the reactive-site ratio, concentration, pH, time, temperature, PEG architecture, and liposome size as a direct test of the framework. The takeaway is stark: compelling biology built on unmeasured surface density is biology that no one can reproduce, and the measurements needed to fix this are available today.

Subject of Research: Maleimide availability and reactive-site accounting in thiol-maleimide peptide conjugation on PEGylated liposomes for hepatic drug delivery

Article Title: Maleimide availability in thiol-maleimide peptide conjugation on PEGylated liposomes: a reactive-site accounting framework illustrated using hepatic drug-delivery systems

Article References: Maroof, K., & Genç, R. (2026). Maleimide availability in thiol-maleimide peptide conjugation on PEGylated liposomes: a reactive-site accounting framework illustrated using hepatic drug-delivery systems. Frontiers in Drug Delivery, 6, Article 1964437. https://doi.org/10.3389/fddev.2026.1964437

Image Credits: AI Generated

DOI: 10.3389/fddev.2026.1964437

Keywords: PEGylated liposomes, thiol-maleimide conjugation, maleimide hydrolysis, hepatocellular carcinoma, peptide targeting, conjugation efficiency, ligand density, DSPE-PEG-maleimide, nanocarrier functionalization, hepatic drug delivery, reactive-site accounting, surface functionalization

The problem the researchers set out to address is a fundamental one. Autografts, the tissue harvested from a patient’s own hamstring, quadriceps, or patellar tendon, remain the preferred choice for anterior cruciate ligament reconstruction because they reliably incorporate into the body and produce strong long-term outcomes. But they come with real costs: donor-site morbidity, limited tissue availability, prolonged rehabilitation, and postoperative pain. Allografts, tissue from cadavers, eliminate the donor-site problem but introduce concerns about slower biological incorporation, tissue availability, and potential immunological or infectious complications. Synthetic grafts made from PET, such as the Ligament Advanced Reinforcement System (LARS), were designed to sidestep these issues entirely by providing immediate mechanical stability without requiring any donor tissue at all.

Yet PET has a critical flaw. The material is intrinsically bioinert, meaning its hydrophobic and chemically unreactive surface resists protein adsorption, cellular attachment, and tissue ingrowth. First-generation synthetic ligaments built from PET and similar polymers were largely abandoned after high rates of mechanical failure, wear debris generation, chronic synovitis, and degenerative joint changes. Even the LARS system, which remains the most widely used and clinically investigated PET-based device, has shown encouraging short- to mid-term results but faces persistent questions about long-term biological incorporation. The surface of PET simply does not invite the body’s cells to attach, proliferate, and build new tissue the way a natural ligament does.

The Italian research team, led by Luca Bertolino and colleagues, conducted their systematic review according to the PRISMA 2020 guidelines, searching PubMed, Embase, and Web of Science up to August 20, 2026. They included only original research articles investigating chemically or biologically modified PET grafts for ACL reconstruction that reported in vitro cellular outcomes, in vivo animal model data, and mechanical properties. Two independent reviewers performed screening, full-text assessment, and data extraction. From an initial pool of 83 records, 36 duplicates were removed, 47 articles were screened by title and abstract, 27 underwent full-text inspection, and 17 ultimately met all inclusion criteria.

The functionalization strategies identified across these studies fell into four broad categories. Physical deposition methods, described in three studies, included pulsed laser deposition of bioactive glass nanocoatings and plasma spraying of hydroxyapatite particles onto the PET surface. Chemical surface modifications, the largest category with seven studies, ranged from layer-by-layer electrostatic assembly of hyaluronic acid and cationized gelatin multilayers to ozonation-induced graft polymerization of polystyrene sodium sulfonate, graphene transfer via a poly(methyl methacrylate)-assisted process, collagen coating with simvastatin-loaded microspheres, silk fibroin crosslinking, and polydopamine interlayer formation with subsequent BMP-2 immobilization. Biomimetic mineral coatings, described in five studies, involved hydroxyapatite deposition through alternate soaking, electrodeposited calcium phosphate, and strontium-substituted hydroxyapatite nanoparticles synthesized via microwave-hydrothermal reaction. A single study took a hybrid approach, combining electrospun polycaprolactone nanofibrous membranes loaded with BMP-7 with a PET mesh fabric rolled into a multilayered structure.

Across all seventeen studies, the functionalized PET scaffolds demonstrated improved performance compared with unmodified PET controls. In vitro, the modified surfaces showed enhanced cellular proliferation, upregulation of osteogenic markers including alkaline phosphatase, RUNX2, BMP-2, osteocalcin, osteopontin, and collagen type I, and increased angiogenic activity marked by elevated vascular endothelial growth factor expression. Surface characterization confirmed that the functionalization techniques consistently increased surface roughness and hydrophilicity, with water contact angles dropping from approximately 115 degrees on pristine PET to as low as 30 degrees on some coated scaffolds. These physicochemical changes facilitate protein adsorption and integrin-mediated cell adhesion, which the authors identify as the first critical step in establishing a regenerative microenvironment at the graft-bone interface.

The in vivo evidence, drawn from 726 animals across the included studies, painted a consistent picture of improved graft-bone integration. Micro-computed tomography revealed higher bone volume fraction at the graft-bone interface in functionalized groups, with some studies reporting bone volume fractions more than doubling compared with unmodified PET. Bone tunnel areas were consistently smaller in the functionalized groups, indicating reduced bone resorption around the implant. Histological analysis showed narrower graft-bone interface widths, with some coatings reducing the fibrous tissue layer from over 400 micrometers to under 100 micrometers by twelve weeks post-implantation. One study using a copper-containing bioactive glass coating reported new bone width of 52 micrometers at the interface compared with just 4 micrometers for unmodified PET at the same time point.

Mechanical testing generally favored the functionalized scaffolds as well, though the improvements were measured after implantation rather than before, suggesting that the gains came from enhanced biological fixation rather than from any change in the intrinsic material properties. Ultimate load to failure increased by as much as 2.7-fold in some comparisons, with one study reporting 502 newtons for a hydroxypropylcellulose-coated graft versus 183 newtons for unmodified PET at sixteen weeks in beagle dogs. Stiffness values similarly favored the modified grafts. However, when compared directly with the native anterior cruciate ligament, even the best-performing functionalized PET scaffolds fell short, reaching approximately 70 percent of native ACL strength and 46 percent of native ACL stiffness in the studies that made such comparisons.

The authors emphasize that these findings should be interpreted with significant caution. The SYRCLE risk of bias assessment revealed that all seventeen studies were rated as having an unclear or high risk of bias for most methodological domains, with none reporting adequate blinding of caregivers and investigators. The animal models were predominantly New Zealand rabbits, which accounted for 82 percent of all animals studied, with only limited use of larger species such as goats, sheep, dogs, and pigs that more closely approximate human knee anatomy and loading conditions. Outcome reporting was inconsistent, with key parameters such as ligamentization and angiogenesis assessed in only a small subset of studies using non-standardized methods. The substantial heterogeneity in functionalization techniques, animal models, follow-up durations, and outcome measures prevented any meta-analysis and made it impossible to determine which specific coating strategy was most effective.

Despite these limitations, the review establishes an important proof of concept. Surface biofunctionalization, rather than the base material itself, appears to be the key determinant of scaffold performance in ACL reconstruction. The consistent pattern of improvements across diverse coating strategies suggests that the biological inertness of PET can be effectively addressed regardless of the specific technique employed, since host tissue response is closely tied to surface properties. The authors propose that next-generation synthetic ligaments should be designed as multifunctional systems with spatially controlled functionalization, allowing the bone-facing portion of the scaffold to promote osteointegration while maintaining an appropriate biological environment for ligament tissue formation along the intra-articular portion. Before clinical translation, however, the field will need standardized experimental protocols, harmonized outcome measures, larger animal models with longer follow-up periods, and ultimately well-designed clinical studies to determine whether the biological and biomechanical advantages observed in preclinical models translate into improved patient outcomes.

Subject of Research: Surface functionalization of polyethylene terephthalate scaffolds for anterior cruciate ligament reconstruction

Article Title: Surface engineering strategies for PET-Based ligament scaffolds in anterior cruciate ligament reconstruction: a systematic review of mechanical and biological performances

Article References: Bertolino, L., Picchi, A., Resta, S., Oliva, P., Fidanza, A., & Bonanzinga, T. (2026). Surface engineering strategies for PET-Based ligament scaffolds in anterior cruciate ligament reconstruction: a systematic review of mechanical and biological performances. Frontiers in Bioengineering and Biotechnology, 14, Article 1916072. https://doi.org/10.3389/fbioe.2026.1916072

Image Credits: AI Generated

DOI: 10.3389/fbioe.2026.1916072

Keywords: ACL reconstruction, PET scaffolds, surface functionalization, synthetic ligaments, tissue engineering, hydroxyapatite coating, graft-bone integration, osseointegration, biomaterials, LARS, preclinical studies, ligamentization

TMV has long been a favorite of structural biologists and nanotechnologists alike. The virus consists of 2,130 identical copies of a 17.5-kilodalton coat protein wound helically around a 6.4-kilobase RNA genome, forming a rigid rod roughly 300 nanometers long and 18 nanometers wide, with a hollow central channel about 4 nanometers across. Because the particle self-assembles with stoichiometric precision and presents a highly repetitive, accessible surface, researchers have used it as a scaffold for dyes, peptides, and therapeutic cargos. Crucially, TMV assembly can be nucleated by a specific RNA element known as the origin of assembly sequence (OAS), which means heterologous RNAs bearing this packaging signal can be selectively encapsidated.

Conventional surface modification of TMV, however, has relied on chemically coupling molecules to naturally occurring reactive residues such as lysines or cysteines scattered across the coat protein. That approach often yields heterogeneous products with poorly controlled ligand orientation, a serious drawback when displaying biologically active proteins, antibodies, or receptor-binding ligands whose function depends on correct presentation. The UCLA team, led by William M. Gelbart and Charles M. Knobler, instead genetically encoded a short peptide motif, LPETG, at the C-terminus of every coat protein. LPETG is the recognition sequence for Sortase A (SrtA), a transpeptidase from Staphylococcus aureus that swaps the motif for any molecule bearing an N-terminal polyglycine tag, forming a covalent bond in a site-specific and directional manner.

A key constraint shaped the choice of production host. Assembly-competent TMV coat protein requires eukaryotic post-translational processing: the initiator methionine must be removed and the exposed N-terminal serine acetylated. Bacteria generally cannot do this, so the researchers turned to Komagataella phaffii, the methylotrophic yeast formerly known as Pichia pastoris, which grows rapidly, scales well, and performs the necessary maturation. Previous studies had shown that TMV-like particles can self-assemble in yeast, but the new work adds two crucial elements: a sortase-addressable surface and a self-amplifying RNA cargo.

For the cargo, the team borrowed from Nodamura virus, an insect alphanodavirus whose RNA1 replicon can replicate autonomously in yeast. They designed a replicon encoding the NoV RNA-dependent RNA polymerase and a luciferase reporter, flanked by the NoV untranslated regions needed for replication, and carrying the TMV OAS. A hepatitis delta virus ribozyme at the 3′ end generates a defined RNA terminus, while a Thosea asigna virus 2A sequence lets the polymerase and luciferase be produced as separate proteins. Once the initial positive-sense transcript is translated, the polymerase amplifies the RNA, and a subgenomic promoter on the negative-sense intermediate directs synthesis of a shorter, roughly 1,800-nucleotide RNA. The idea is that replicating RNA bearing the OAS will be preferentially packaged by the coat protein inside the cell, eliminating the need to produce and purify RNA and protein separately for in vitro assembly.

The evidence that this worked came from several directions. Transmission electron microscopy of particles purified from yeast lysates by sucrose cushion and cesium chloride gradient centrifugation revealed rods with wild-type TMV morphology. Length analysis of 200 particles showed a bimodal distribution centered near 100 and 200 nanometers. Because TMV rod length is dictated by the encapsidated RNA at a ratio of about 4.7 nanometers per 100 nucleotides, the longer population matches the predicted 211-nanometer length for the full 4,563-nucleotide replicon transcript, while the shorter population is consistent with the 1,825-nucleotide subgenomic RNA, which can only exist if replication occurred inside the yeast cells. The authors note that fragmentation during purification cannot be excluded, but the correspondence between observed and predicted lengths strongly suggests the intended RNA was incorporated.

RT-PCR on RNA extracted from the purified particles confirmed the presence of sequences from the NoV-RdRp-Luc-OAS construct, yielding amplicons of the expected 4.5-kilobase and 1.8-kilobase sizes that matched the anticipated regions by sequencing. Before extraction, the team treated particles with RNase A and washed away unprotected RNA, so the recovered sequences represent RNA genuinely shielded inside the capsid rather than contaminating debris. The researchers are careful to point out that the 1.8-kilobase product alone cannot prove replication, since that region also exists within the full-length transcript, but the bimodal particle lengths provide independent corroboration.

The functionalization experiments delivered the most striking results. Incubating intact nanorods with Sortase A and an N-terminal polyglycine Alexa Fluor 488 probe produced a fluorescent band at the expected conjugated molecular weight on SDS-PAGE, visible only when all three reaction components were present. At higher dye-to-coat-protein ratios the team achieved conjugation levels up to 80 percent, though they kept the reaction deliberately modest in the published gels to keep bands distinct. Even more impressive was the conjugation of a polyglycine-tagged affibody, a small 7.9-kilodalton engineered binding protein based on the Z domain of protein A. Here the conjugated band, at roughly 27.9 kilodaltons, dominated the gel, indicating around 80 percent modification efficiency while the rod morphology remained intact under the electron microscope.

To prove that the displayed affibody was not just attached but accessible, the researchers exploited an exposed cysteine on the affibody to couple 5-nanometer maleimide-activated gold nanoparticles via thiol-maleimide chemistry. Because such small gold labels are hard to see directly, they enlarged them with a silver-gold enhancement reagent before imaging. Transmission electron microscopy then showed multiple gold particles studding the surfaces of individual nanorods, direct structural evidence that the conjugated ligands project outward from the assembled particles and remain chemically addressable.

The broader significance lies in manufacturing. In vitro assembly of TMV particles offers fine control but requires independent production and purification of coat protein and RNA cargo followed by controlled assembly reactions, a multistep workflow that complicates scale-up. Producing conjugatable, RNA-loaded nanorods directly in yeast collapses those steps into a single biological system, and K. phaffii is already a workhorse of industrial biotechnology. The authors envision the platform extending to antibodies, enzymes, imaging agents, and other targeting ligands, with future work aimed at improving RNA packaging specificity, characterizing the encapsidated RNA species more thoroughly, and testing how different surface ligands affect cellular uptake and in vivo biological activity. If those efforts succeed, the humble tobacco mosaic virus, once a footnote in plant pathology, may become a modular chassis for precision nanomedicine.

Subject of Research: Enzyme-mediated site-specific functionalization of RNA-containing Tobacco mosaic virus-like nanorods produced in yeast

Article Title: Enzyme-mediated site-specific functionalization of mRNA-containing TMV nanorods produced in yeast

Article References: Tisnado, J., Duran Meza, A. L., Moreno Gutierrez, D. S., Harpell, N. M., Cruz, A., Knobler, C. M., & Gelbart, W. M. (2026). Enzyme-mediated site-specific functionalization of mRNA-containing TMV nanorods produced in yeast. Frontiers in Virology, 6, Article 1955107. https://doi.org/10.3389/fviro.2026.1955107

Image Credits: AI Generated

DOI: 10.3389/fviro.2026.1955107

Keywords: Tobacco mosaic virus, virus-like particles, Sortase A, Komagataella phaffii, nanorods, RNA packaging, origin of assembly sequence, affibody, gold nanoparticles, Nodamura virus replicon, surface functionalization, nanobiotechnology

The secret to DLC’s versatility lies in its structure. The term does not describe a single material but a broad family of metastable amorphous carbon coatings characterized by different ratios of sp2 and sp3 hybridized bonds, often containing hydrogen or additional dopants. Carbon atoms with sp3 hybridization form tetrahedral bonds similar to those in diamond, delivering high hardness, high elastic modulus, excellent wear resistance, and a wide electronic bandgap. In contrast, sp2 hybridization produces graphitic structures with delocalized pi electrons, leading to higher electrical conductivity at the expense of hardness. Because most DLC films contain mixtures of both bonding states, their functional properties can be tailored by controlling deposition parameters and film composition, allowing engineers to dial in hardness, friction coefficient, electrical conductivity, optical transparency, chemical inertness, and biocompatibility.

Hydrogen incorporation represents another fundamental lever. Hydrogenated DLC films generally exhibit lower residual stress, reduced friction coefficients, improved chemical stability, and smoother surfaces compared with hydrogen-free coatings, but excessive hydrogen may reduce hardness, thermal stability, and wear resistance. The article classifies DLC materials into hydrogen-free amorphous carbon, hydrogenated amorphous carbon, tetrahedral amorphous carbon, doped systems, and advanced engineered architectures such as nanocomposite, multilayer, and graded films. Silicon incorporation can improve oxidation resistance, thermal stability, and adhesion while reducing internal stress, nitrogen doping modifies electrical conductivity, fluorine reduces surface energy and enhances hydrophobicity, and metallic dopants including tungsten, titanium, chromium, and silver have been investigated to improve conductivity, tribological behavior, catalytic activity, or antibacterial performance.

Why does this matter now? The rapid evolution of microsystems is reshaping the requirements imposed on engineering materials. Wearable healthcare devices, autonomous sensors, implantable medical systems, intelligent manufacturing, space exploration, and distributed Internet of Things networks all demand materials capable of performing multiple functions beyond conventional structural support. At the microscale, where surface forces dominate over inertial forces, the low coefficient of friction exhibited by many DLC coatings plays a crucial role in minimizing stiction, reducing energy losses, and extending device lifetime in microelectromechanical systems. Equally important is the outstanding chemical stability of DLC, which provides effective protection against corrosion, oxidation, and surface degradation in biological fluids, high humidity, and extreme temperatures, ensuring stable operation over prolonged periods.

The article is careful to note that DLC should not be regarded as a universal replacement for other functional thin-film materials. Silicon carbide offers excellent thermal stability for harsh-environment MEMS, silicon nitride and alumina provide outstanding dielectric properties, titanium nitride is widely employed as a hard conductive coating, and graphene exhibits exceptional electrical conductivity and flexibility. Polymeric coatings such as parylene offer excellent conformality but lower hardness, while self-assembled monolayers provide molecular-scale functionalization but lack mechanical robustness. DLC occupies a unique position by simultaneously combining high hardness, low friction, chemical inertness, tunable electrical properties, optical transparency, and excellent biocompatibility within a single coating platform, although these advantages are often accompanied by challenges related to residual stress, adhesion, and process optimization.

On the manufacturing side, plasma-enhanced chemical vapor deposition remains the most widely adopted technique for DLC synthesis because of its relatively low processing temperature, good film uniformity, and compatibility with complex three-dimensional geometries. Physical vapor deposition methods, including magnetron sputtering and filtered cathodic vacuum arc, have also gained considerable attention, while high-power impulse magnetron sputtering offers enhanced plasma ionization and improved control over film density, adhesion, and microstructure. One of the most important challenges for future deposition technologies is achieving high-performance DLC coatings at temperatures compatible with complementary metal–oxide–semiconductor processing and flexible polymer substrates, which will be essential for integrating DLC with flexible electronics, wearable sensors, and heterogeneous microsystems without compromising existing electronic components.

Characterization is equally critical, since the properties of DLC are highly sensitive to bonding configuration, hydrogen content, residual stress, and defect density. Raman spectroscopy remains the most widely employed tool for evaluating structural organization, providing valuable information on disorder and sp2 clustering, but it alone cannot accurately quantify the sp3 fraction and should be interpreted together with other techniques. X-ray photoelectron spectroscopy enables investigation of surface chemistry and dopant incorporation, electron energy loss spectroscopy offers insights into carbon hybridization, Fourier transform infrared spectroscopy identifies hydrogen bonding configurations, and nanoindentation remains the standard technique for measuring hardness and elastic modulus. Depending on the intended application, additional methods such as scratch testing, ball-on-disk tribometry, and electrochemical impedance spectroscopy assess adhesion, tribological performance, and corrosion resistance.

The emerging applications are striking. In flexible and stretchable microsystems, careful control of deposition parameters, hydrogen content, film thickness, and doping enables DLC coatings with reduced residual stress and improved flexibility suitable for polymeric substrates, while structural engineering approaches such as island-bridge layouts, serpentine interconnects, and kirigami-inspired geometries accommodate large mechanical deformation. In BioMEMS and biomedical microdevices, properly engineered DLC surfaces can support cell adhesion while minimizing inflammatory responses, and surface functionalization enables highly selective biosensors capable of detecting biomarkers, pathogens, or metabolites. The article emphasizes that biological evaluation should rely on standardized testing protocols from the ISO 10993 series rather than isolated biocompatibility claims, since protein adsorption, hemocompatibility, and bacterial colonization depend strongly on surface chemistry, roughness, wettability, and elemental doping.

Looking further afield, DLC coatings could improve the durability and performance of microbatteries, microsupercapacitors, piezoelectric and triboelectric energy harvesters, and miniaturized power management devices. Hybrid structures combining DLC with two-dimensional materials or carbon nanostructures may lead to devices with enhanced sensing capabilities, improved charge transport, and superior mechanical performance, potentially enabling applications in photonic microsystems, quantum sensing, and high-performance environmental monitoring. Machine learning algorithms, high-throughput experimentation, and real-time process monitoring may accelerate the optimization of deposition parameters and material properties, and sustainability is likely to become an important driver, with low-temperature deposition processes and energy-efficient manufacturing routes reducing the environmental impact of thin-film fabrication.

Significant barriers remain before DLC’s full potential can be realized. Precise control of residual stress directly influences film adhesion, mechanical reliability, and long-term stability, and stress management continues to limit the deposition of thick, defect-free coatings and their integration with fragile microstructures. From an industrial perspective, reproducibility and scalability remain significant obstacles: achieving uniform coatings over large areas, ensuring consistent film properties across production batches, and establishing standardized characterization and qualification protocols are critical steps toward commercial implementation. The article outlines a phased outlook, with short-term efforts focused on deposition reproducibility and CMOS-compatible low-temperature processes, medium-term advances emphasizing multifunctional coatings and AI-assisted process optimization, and longer-term convergence with intelligent manufacturing and self-powered microsystems. The future impact of diamond-like carbon, the article concludes, will depend on the convergence of materials science, microfabrication, device engineering, and sustainable manufacturing, transforming DLC into a key enabling material for reliable, multifunctional, and highly integrated microsystems supporting advances in healthcare, environmental monitoring, smart manufacturing, and future microelectronic devices.

Subject of Research: Diamond-like carbon films as multifunctional platform materials for MEMS, flexible electronics, and biomedical microdevices

Article Title: Future directions for diamond-like carbon in microsystems and microdevices

Article References: Fraga, M. A. (2026). Future directions for diamond-like carbon in microsystems and microdevices. Frontiers in Carbon, 5, Article 1924248. https://doi.org/10.3389/frcrb.2026.1924248

Image Credits: AI Generated

DOI: 10.3389/frcrb.2026.1924248

Keywords: diamond-like carbon, DLC films, MEMS, microsystems, thin-film deposition, CMOS compatibility, biocompatibility, flexible electronics, residual stress, surface functionalization, tribology, BioMEMS

The research, published in Discover Chemistry, focused on mixed-phase copper oxide nanoparticles containing both CuO and Cu2O crystalline phases. Rather than applying the bare particles directly, the team wrapped them in polyethyleneimine, or PEI, a cationic polymer densely studded with amine groups. The idea rests on a straightforward but powerful principle: the toxicity of copper oxide nanoparticles is largely driven by the redox-active release of copper ions, which catalyze the production of reactive oxygen species inside plant tissues. These reactive molecules attack DNA, damage proteins, and overwhelm the plant’s antioxidant defenses. If a coating can act as a barrier that limits copper ion release and keeps particles from clumping together, much of that damage could be prevented before it begins.

Synthesis was carried out by chemical reduction. The researchers dissolved copper sulfate pentahydrate and treated it with EDTA and potassium hydroxide before adding sodium borohydride dropwise in an ice bath, then stabilized the resulting particles with polyvinylpyrrolidone. For the coated version, PEI was introduced before the reducing agent, so the polymer both helped reduce the copper and formed a protective shell around the growing particles in a single step. The solution shifted from light blue to navy blue as the PEI bound the copper, then changed color again as reduction proceeded, a visual hint of the chemistry unfolding in the beaker.

Confirming that the coating was really there required an arsenal of characterization techniques. Ultraviolet-visible spectroscopy showed a shift in the absorption peak from 230 nanometers for the bare particles to 268 nanometers after modification, a red-shift consistent with surface functionalization. Fourier transform infrared spectroscopy told a complementary story: the sharp Cu-O stretching vibration at 607 wavenumbers moved to 630 after coating, and new peaks corresponding to N-H stretching, N-H bending, and C-N stretching appeared, the fingerprints of the PEI layer.

Perhaps the most striking evidence came from dynamic light scattering and zeta potential measurements. Bare copper oxide nanoparticles formed large, unstable aggregates with a hydrodynamic diameter of roughly 700 nanometers and a slightly negative zeta potential of minus 8.20 millivolts, conditions that favor clumping. After PEI coating, the hydrodynamic size dropped dramatically to about 160.5 nanometers and the surface charge swung positive to plus 24.8 millivolts. That positive charge comes from the forest of amine groups on the polymer, which push particles apart through electrostatic repulsion. In other words, the coating did not just decorate the surface; it fundamentally changed how the particles behave in suspension, keeping them small, dispersed, and less likely to form the large agglomerates that can smother seed tissues.

X-ray diffraction revealed a cubic crystalline structure matching reference cards for both CuO and Cu2O, with Cu2O as the dominant phase, and the pattern was essentially unchanged by coating, except for reduced peak intensities due to the amorphous polymer. High-resolution transmission electron microscopy showed cubic-shaped particles with clear crystalline ordering in both versions. X-ray photoelectron spectroscopy sealed the case: bare particles showed only copper and oxygen signals, while the coated particles displayed nitrogen and carbon peaks from the PEI chain, with nitrogen signatures corresponding to primary, secondary, and tertiary amines.

With the materials fully characterized, the team turned to the biological question. Seeds of two agriculturally important crops were tested: Brassica juncea, Indian mustard, a dicot, and Zea mays, maize, a monocot. Twenty seeds of each species were exposed to concentrations ranging from 100 to 2000 milligrams per liter of either bare or coated nanoparticles, with germination percentage and germination index measured after 48 and 72 hours. Germination is a critical early checkpoint for agriculture, since the eventual yield of a crop depends on how successfully its seeds sprout, making it a sensitive sentinel for nanoparticle toxicity.

The results revealed a clear concentration-dependent pattern, and a clear benefit from the coating. In Indian mustard, bare nanoparticles inhibited germination even at 100 milligrams per liter, and at the maximum concentration of 2000 milligrams per liter the germination index fell to just 16.6 after 72 hours. With the PEI-coated particles, germination performance improved markedly at 100 and 500 milligrams per liter, and even at the highest dose the germination index remained better than with the bare particles, indicating reduced nanoparticle-induced stress. The authors attribute this to the polymer acting as a protective barrier, limiting copper ion release and dampening the formation of reactive oxygen species that would otherwise damage cellular structures in the germinating seed.

Maize told a similar but more dramatic story. The monocot seeds proved notably more sensitive to bare copper oxide nanoparticles: at 100 milligrams per liter they still germinated with a germination index of 86 after 72 hours, but at 1000 and 2000 milligrams per liter, germination was completely suppressed to zero. The PEI coating produced a marked reduction in toxicity at low to moderate concentrations, outperforming the bare particles up to 500 milligrams per liter, though even the coated nanoparticles could not rescue germination at the highest doses. The difference between the two species likely reflects physiological and biochemical distinctions between monocots and dicots, a reminder that nanotoxicity is not one-size-fits-all.

The study’s authors are careful about its limits. All experiments were run in duplicate as a preliminary screening, no PEI-only or free copper ion controls were included, and later growth stages were not assessed. Reactive oxygen species measurements and mechanistic studies remain for future work. Still, the central finding stands: surface modification with polyethyleneimine can partially mitigate the phytotoxic effects of copper oxide nanoparticles, particularly at the moderate concentrations most relevant to field applications. As nanotechnology continues to infiltrate agriculture, from targeted agrochemical delivery to disease management, studies like this one suggest that the path to safer nano-enabled farming may lie not in abandoning engineered nanoparticles but in dressing them appropriately before they meet the soil.

Subject of Research: Phytotoxicity of PEI-coated mixed-phase copper oxide nanoparticles in crop seed germination

Article Title: Phytotoxicity assessment of PEI-modified mixed phase copper oxide (CuO/Cu2O) nanoparticles in agricultural plants

Article References: Saini, I., Sharma, H., Devi, K., Sharma, M., Sharma, M., Kumar, M., & Kumar, R. (2026). Phytotoxicity assessment of PEI-modified mixed phase copper oxide (CuO/Cu2O) nanoparticles in agricultural plants. Discover Chemistry, 3(1), Article 449. https://doi.org/10.1007/s44371-026-00890-4

Image Credits: AI Generated

DOI: 10.1007/s44371-026-00890-4

Keywords: copper oxide nanoparticles, polyethyleneimine, phytotoxicity, seed germination, nanotechnology, agriculture, Brassica juncea, Zea mays, reactive oxygen species, surface functionalization, nanotoxicology, agro-nanotechnology

A research team at the Institute of Physics of the Benemérita Universidad Autónoma de Puebla in Mexico, led by Azury Nava Guzmán together with Enrique Sánchez Mora, Anabel Romero López, and Mary Carmen Amador Meléndez, has now systematically mapped how a remarkably humble molecule can tame these unruly particles. Their chosen stabilizer is glycine, the simplest of the amino acids that build proteins. Writing in the Journal of Nanoparticle Research, the team shows that the amount of glycine present during synthesis acts as a dial that tunes crystallite size, particle diameter, surface charge, colloidal behavior, and even the thermal response of zero-valent iron nanoparticles, all without disturbing the metallic iron core itself. The work, published as open access on 13 October 2026, was funded by Mexico’s Secretariat of Science, Humanities, Technology and Innovation.

The synthesis itself is a classic of the field. The researchers dissolved ferric chloride in water under a flowing nitrogen atmosphere at 20 degrees Celsius, then injected sodium borohydride, a strong reducing agent, at a controlled rate. The reaction reduces iron ions to metallic iron while releasing hydrogen gas, and it is exothermic enough that the mixture warms to about 42 degrees Celsius at a pH of roughly 9. The resulting black powder was washed an extraordinary 35 times with acetone, using magnetic separation and sonication between washes, to strip away boron byproducts and residual salts. To functionalize the particles, the team simply added glycine to the iron salt solution before reduction, at three doses: 8, 16, and 32 millimoles, producing samples labeled NPs-FeG1, NPs-FeG2, and NPs-FeG3.

X-ray diffraction delivered the first surprise. Every sample, functionalized or not, showed the sharp reflections of body-centered cubic metallic iron, with characteristic peaks near 45.1, 65.3, and 82.8 degrees in two-theta. Glycine left the crystal structure untouched. But the width of the main (110) peak told a subtler story: it broadened steadily as glycine concentration rose, from a full width at half maximum of 0.94 degrees for bare nanoparticles to 1.62 degrees for the highest glycine dose. Applying Scherrer’s equation, the team calculated that crystallite size shrank progressively from 9.55 nanometers in the unfunctionalized particles to 7.81, 6.65, and finally 5.54 nanometers across the three functionalized samples. Glycine, in other words, behaves like a surfactant at the growing crystal surface, capping the domains of metallic iron before they can enlarge.

Scanning electron microscopy then revealed an apparent paradox. While the crystallites got smaller, the particles got bigger. The average diameter of unfunctionalized nanoparticles measured 58.95 plus or minus 12.80 nanometers, based on 1000 particles analyzed per sample, but the glycine-treated particles grew to 75.51, 83.36, and 83.79 nanometers for the three doses, with the two higher doses essentially indistinguishable. The resolution of the paradox lies in scale: each particle seen under the microscope is a polycrystalline aggregate containing many of the smaller crystalline domains measured by diffraction. Glycine-mediated surface interactions appear to promote the assembly of these larger particles during synthesis, even as they suppress growth within each crystalline domain. All samples, meanwhile, assembled themselves into striking chain-like structures, a hallmark of magnetic dipole-dipole interactions pulling quasi-spherical iron particles nose-to-tail.

The chains are not purely magnetic accidents. The researchers propose a layered interaction model in which surface chemistry plays a decisive role. Metallic iron exposed to water and oxygen during synthesis develops a thin skin of hydroxides and oxyhydroxides such as goethite, lepidocrocite, and ferrihydrite. Hydroxyl groups on this skin can hydrogen-bond with one another on bare particles. When glycine is present, its zwitterionic form, carrying both a positively charged ammonium group and a negatively charged carboxylate, can anchor through its amino end to the hydroxylated surface, leaving the carboxylate groups exposed to the surrounding water. Carboxylates on neighboring particles can then pair up, stitching dimers and chains together. Increasing the glycine dose raises the density of these polar groups on the surface, favoring exactly the hydrogen-bonded agglomerates the microscope revealed.

Infrared spectroscopy backed this mechanism with molecular-level detail. The functionalized particles showed weak O-H stretching bands between 3727 and 3696 inverse centimeters, indicating that glycine modifies the environment of surface hydroxyls. Bands between 2670 and 2678 inverse centimeters, tied to the ammonium group of zwitterionic glycine interacting with surface hydroxyls, appeared only in the functionalized samples. The carboxylate-asymmetric-stretch and ammonium-deformation bands near 1615 to 1565 inverse centimeters shifted progressively to lower frequencies with increasing glycine dose, and a mixed CH2 bending and NH2 torsion band near 810 inverse centimeters moved as well, both signatures of a changing vibrational environment for adsorbed glycine. Bands between 664 and 602 inverse centimeters confirmed Fe-O vibrations from the surface oxide and oxyhydroxide species, which XRD suggested must be present only in small or poorly crystalline amounts, since no bulk oxide phases were detected.

Perhaps the most practically consequential result came from zeta potential measurements, a proxy for colloidal stability. Bare nanoparticles carried a zeta potential of minus 22.95 millivolts, indicating only limited stability in water. The lowest glycine dose pushed the value to minus 32.83 millivolts, the most negative of all samples, reflecting exposed carboxylate groups and stronger electrostatic repulsion between particles. But the story reversed at higher doses: the 16 and 32 millimole samples dropped to just minus 10.07 and minus 9.68 millivolts. The team attributes this to charge shielding by dense glycine coverage, which lets hydrogen bonding and dipole-dipole forces between amino and carboxyl groups outweigh electrostatic repulsion, promoting the agglomeration seen by electron microscopy. The lesson is that more stabilizer is not always better; for zero-valent iron, the sweet spot for colloidal stability sits at the lowest glycine concentration tested.

Thermal analysis added a final dimension. Thermogravimetric curves showed multistage behavior for all samples: water desorption below 150 degrees Celsius, dehydroxylation of oxyhydroxides and gradual oxidation of metallic iron between 200 and 600 degrees, and a pronounced mass gain above 600 degrees as iron takes up oxygen. The functionalized samples added a distinct mass loss between 150 and 350 degrees Celsius corresponding to glycine decomposition, and the oxidation-related mass changes were less pronounced than in bare particles, suggesting glycine partially delays oxidation. The team also tracked the Curie transition near 770 degrees Celsius, where the particles lose their ferromagnetism and the apparent mass recorded by the balance jumps, an instrumental artifact the authors carefully disentangled from real oxidation. Raman spectra of the heat-treated residues revealed hematite and beta-FeOOH in all samples, with the functionalized residues additionally showing lepidocrocite signatures, confirming that the organic layer reshapes the thermal degradation pathway of the particles.

What makes this study notable is its systematic dose-response design applied to metallic iron rather than the iron oxides that dominate the glycine literature. Most prior work on glycine and iron nanomaterials focused on magnetite and related oxides, whose chemistry cannot simply be extrapolated to a reactive metallic core. By demonstrating that glycine concentration independently tunes crystallite growth, particle aggregation, surface charge, and thermal stability while preserving the body-centered cubic iron phase, the Mexican team has provided a practical recipe book for engineers designing zero-valent iron materials. The implications reach into groundwater remediation, where better-dispersed particles could intercept contaminants more efficiently; into catalysis, where surface chemistry governs electron transfer; and toward emerging biomedical and biosensing applications, where amino-acid coatings offer a biocompatible interface. The next step, the authors note, will be surface-sensitive techniques such as X-ray photoelectron or Mössbauer spectroscopy to pin down the exact oxidation states at the glycine-iron interface.

Subject of Research: Effect of glycine concentration on the physicochemical properties of glycine-functionalized zero-valent iron nanoparticles

Article Title: Glycine-functionalized zero-valent iron nanoparticles: effect of glycine concentration on physicochemical properties

Article References: Guzmán, A. N., Mora, E. S., López, A. R., & Meléndez, M. C. A. (2026). Glycine-functionalized zero-valent iron nanoparticles: effect of glycine concentration on physicochemical properties. Journal of Nanoparticle Research, 28(10), Article 264. https://doi.org/10.1007/s11051-026-06787-8

Image Credits: AI Generated

DOI: 10.1007/s11051-026-06787-8

Keywords: zero-valent iron, nanoparticles, glycine, surface functionalization, X-ray diffraction, zeta potential, colloidal stability, FTIR spectroscopy, thermogravimetric analysis, Raman spectroscopy, environmental remediation, nanoparticle synthesis

The appeal of amla lies in its chemistry. The fruit is exceptionally rich in polyphenols, flavonoids, tannins, gallic acid, ellagic acid, and ascorbic acid, a cocktail of molecules carrying hydroxyl and carboxyl groups that can donate electrons to silver ions, converting dissolved Ag+ into metallic Ag0. In the reported procedure, fresh fruits collected from cultivated plants in Tiruchirappalli, Tamil Nadu, were washed, cut, and extracted in deionized water at a moderate 60 to 70 degrees Celsius for 15 to 20 minutes, conditions chosen to dissolve water-soluble phenolics without destroying heat-sensitive constituents such as vitamin C. When this amber extract was dripped into stirred silver nitrate solutions, the mixture darkened from pale yellow to deep brown, the classic visual signature of nanoparticle formation.

A central question the researchers addressed is how the concentration of the silver nitrate precursor shapes the final product. They ran the synthesis at two concentrations, 0.1 M and 0.2 M, reasoning that precursor availability governs nucleation rate, crystal growth, particle size distribution, and aggregation. At lower concentrations, nucleation proceeds more gradually and particles interact less; at higher concentrations, abundant silver ions promote growth, broaden the size distribution, and increase collision-driven aggregation. Because these structural differences feed directly into the localized surface plasmon resonance, the collective oscillation of conduction electrons that gives silver nanoparticles their distinctive color and optical response, concentration control becomes a practical dial for tuning the material.

Optical measurements confirmed the chemistry. Ultraviolet-visible spectroscopy showed a sharp absorption maximum at 444 nanometers, the hallmark plasmon band of silver nanoparticles, for the 0.1 M sample. The 0.2 M sample, by contrast, displayed a broadened spectrum extending toward the near-infrared, with a broad feature centered near 896 nanometers. The authors are careful in their interpretation: rather than a distinct resonance of individual spheres, this long-wavelength feature most likely reflects particle aggregation, plasmonic coupling between closely spaced nanoparticles, a wider size distribution, and multiple scattering in the more concentrated colloid. Notably, they caution that because transmission electron microscopy and dynamic light scattering were not performed, this mechanism is presented as a reasonable interpretation rather than direct experimental proof.

Structural analysis by X-ray diffraction established the quality of the product. Diffraction peaks at approximately 38, 44, 64, and 77 degrees two-theta matched the (111), (200), (220), and (311) planes of face-centered cubic metallic silver, in good agreement with standard reference data, and no impurity or oxide peaks appeared. The sharp, intense reflections indicate good crystallinity, while their broadening points to nanoscale dimensions that can be quantified through the Debye-Scherrer relation. Slight differences in peak intensity between the two samples hint at concentration-dependent variations in particle size and crystalline perfection, evidence that the plant-derived molecules not only reduce the silver but also stabilize growing crystallites against uncontrolled clumping.

Infrared spectroscopy illuminated the surface chemistry responsible for that stabilization. A prominent absorption band near 1384 inverse centimeters, attributed to C-O stretching vibrations and symmetric carboxylate stretching, revealed oxygen-containing functional groups from the fruit’s biomolecules adsorbed on the nanoparticle surfaces. The authors are candid about the limits of this technique: FTIR identifies functional groups, not individual molecules, and because the spectrum of the pristine extract was not recorded, the data demonstrate the presence of surface-associated biomolecular groups rather than definitive proof of specific phytochemical binding. They outline plans for comparative FTIR, X-ray photoelectron spectroscopy, Raman, and nuclear magnetic resonance measurements, alongside chromatographic profiling of the extract, to pin down the ligand-nanoparticle interactions directly.

Photoluminescence measurements added another layer to the optical story. The nanoparticles emitted broad bands at roughly 360, 410, and 520 nanometers, spanning the visible region. Crucially, the researchers reject a semiconductor-style interpretation: metallic silver has no band gap, so the emission cannot arise from band-edge or defect-mediated electron-hole recombination. Instead, they attribute the luminescence to surface-associated electronic states, plasmon-assisted radiative relaxation, interactions between conduction electrons and adsorbed biomolecules, and residual organic species from the extract that remain attached after synthesis. The Tauc-type plots the team constructed from the absorption data are likewise presented purely as comparative optical fingerprints, not as true band-gap values, a level of interpretive restraint that is refreshingly unusual in this literature.

Scanning electron microscopy completed the physical picture, revealing predominantly quasi-spherical to irregular particles with an average size of roughly 200 nanometers and a moderate degree of agglomeration, particularly at the higher precursor concentration. Such clustering is typical of plant-mediated synthesis, where multiple phytochemicals simultaneously participate in nucleation, growth, and capping, producing inherent heterogeneity; drying during sample preparation can add further clustering. At 200 nanometers, quantum confinement effects are negligible, reinforcing the authors’ conclusion that the observed spectral differences between the 0.1 M and 0.2 M samples stem from plasmonic interactions, morphology, and surface chemistry rather than semiconductor-like electronic transitions. The study thus builds a clear structure-property relationship linking precursor concentration to particle growth, aggregation, and optical response.

The broader significance is twofold. Practically, the work demonstrates that a cheap, abundant, antioxidant-rich fruit can replace hazardous reagents in producing phase-pure, crystalline silver nanoparticles whose plasmonic and luminescent properties can be tuned simply by adjusting precursor concentration, an attractive proposition for antimicrobial coatings, biomedical devices, sensing platforms, and optoelectronic components. Methodologically, the paper models careful scientific communication, explicitly flagging what its data can and cannot show, from the absence of extract-side FTIR controls to the lack of TEM or DLS size measurements, and committing to chemically synthesized control samples in future work. In a field often criticized for overclaiming, that transparency may prove as influential as the nanoparticles themselves.

Subject of Research: Green synthesis and surface functionalization of silver nanoparticles using Phyllanthus emblica fruit extract

Article Title: Green synthesis and surface functionalization of silver nanoparticles using phyllanthus emblica fruit extract

Article References: Banu, K. B., & Mary, I. A. (2026). Green synthesis and surface functionalization of silver nanoparticles using phyllanthus emblica fruit extract. Discover Chemistry, 3(1), Article 489. https://doi.org/10.1007/s44371-026-00938-5

Image Credits: AI Generated

DOI: 10.1007/s44371-026-00938-5

Keywords: silver nanoparticles, green synthesis, Phyllanthus emblica, surface functionalization, surface plasmon resonance, phytochemicals, X-ray diffraction, FTIR spectroscopy, photoluminescence, scanning electron microscopy, nanotechnology, sustainable chemistry

The review organizes the field into eight distinct material families, each with its own physical principles, synthetic chemistry, and diagnostic strengths. These are quantum dots, gold nanostructures, carbon-based nanomaterials, silica-based nanoparticles, superparamagnetic iron oxide nanoparticles, aggregation-induced emission nanoparticles, nanobubbles, and polymeric nanomaterials. The classification is more than a cataloging exercise. By deconstructing the structure-property paradigms of each family, the authors establish design rules that connect the atomic-scale architecture of a nanoparticle to its observable performance inside a living body, from the wavelength of light it emits to the way it navigates the turbulent microenvironment of a tumor or an inflamed tissue.

Quantum dots remain among the most celebrated of these platforms. These semiconductor nanocrystals, typically only a few nanometers across, absorb light over broad spectral ranges and re-emit it at sharply defined wavelengths determined by their physical size. That size-tunable fluorescence, combined with exceptional brightness and resistance to photobleaching, allows researchers to track biological processes over long observation periods with single-particle sensitivity. The review emphasizes that modern synthetic methodologies now permit precise control over quantum dot composition, shell architecture, and surface chemistry, which in turn governs their optical quantum yield, colloidal stability, and crucially their biological compatibility. Surface functionalization strategies, such as coating the inorganic core with biocompatible ligands or amphiphilic polymers, transform otherwise toxic crystalline materials into probes that can circulate through the bloodstream and accumulate selectively at disease sites.

Gold nanomaterials occupy a complementary niche in the imaging arsenal. Depending on their shape, whether spherical nanoparticles, rods, shells, or stars, gold nanostructures support localized surface plasmon resonances, collective oscillations of conduction electrons that produce intense optical scattering and absorption. This property makes them powerful contrast agents for optical coherence tomography, photoacoustic imaging, and computed tomography, while their chemical inertness and ease of surface modification with thiolated molecules give synthetic chemists an unusually versatile handle. The authors highlight how the geometry of a gold nanoparticle can be tuned during synthesis to shift its plasmon resonance deep into the near-infrared window, the spectral region where biological tissue is most transparent, enabling imaging at centimeter depths with millimeter-scale resolution.

Carbon-based nanomaterials, including carbon dots, graphene quantum dots, and carbon nanotubes, bring a different set of advantages to the table. Derived from abundant and often biologically benign precursors, carbon dots exhibit strong fluorescence, low toxicity, and rich surface chemistry that supports straightforward conjugation to targeting ligands, drugs, or responsive groups. Their small hydrodynamic diameters promote efficient renal clearance, a biosafety attribute of growing importance as regulators scrutinize the long-term fate of engineered nanomaterials in the body. The review also situates silica-based nanoparticles within this design landscape, noting that mesoporous silica architectures provide exceptionally high surface areas and controllable pore structures that can host imaging agents, protect them from premature degradation, and release them in response to specific pathophysiological cues such as acidic pH or elevated glutathione levels.

Superparamagnetic iron oxide nanoparticles represent the workhorses of magnetic resonance imaging contrast enhancement. Because each nanoparticle behaves as a single magnetic domain, these materials generate strong local field inhomogeneities that shorten the relaxation times of nearby water protons, darkening the corresponding regions in T2-weighted and, for smaller cores, brightening them in T1-weighted magnetic resonance images. The authors stress that synthetic control over core size, crystallinity, and coating thickness directly determines the relaxivity, the quantitative measure of contrast efficiency, and that recent breakthroughs have pushed these agents toward molecular-level sensitivity in preclinical studies of cardiovascular disease, neuroinflammation, and cancer metastasis. Iron oxide also carries the advantage of clinically established chemistry, with several formulations already approved for human use in related applications.

Perhaps the most conceptually intriguing family covered in the review is that of aggregation-induced emission nanoparticles. Conventional organic fluorophores suffer from aggregation-caused quenching, a phenomenon in which densely packed dye molecules lose their luminescence through nonradiative energy dissipation. Aggregation-induced emission materials invert this behavior: they are nearly dark when molecularly dissolved but grow brilliantly luminous when their molecular motions are restricted, as happens when they aggregate into solid nanoparticles or bind to biological structures. This counterintuitive property makes them exceptionally resistant to photobleaching, ideal for long-term cell tracking, and highly effective as bright solid-state probes for fluorescence imaging deep within tissues. The review traces how synthetic strategies, including the incorporation of tetraphenylethylene and related propeller-shaped building blocks, have produced AIE nanoparticles with emission spanning the visible and near-infrared spectra and with built-in responsiveness to reactive oxygen species, enzymes, and other biomarkers of disease.

The remaining two families extend the multiscale reach of the platform concept in different physical directions. Nanobubbles, gas-filled or gas-generating structures on the scale of hundreds of nanometers, serve as contrast agents for ultrasound imaging, the most widely deployed and least expensive modality in clinical medicine, and their acoustic responsiveness can be harnessed both for diagnosis and for triggered delivery of therapeutic payloads. Polymeric nanomaterials, assembled from biodegradable polymers such as polylactic-co-glycolic acid, polyethylene glycol derivatives, and polypeptides, act as modular carriers that can integrate multiple imaging functions, fluorescence, magnetic resonance, photoacoustic, or positron emission signals, within a single tunable particle whose size, charge, and degradation profile are dictated by polymer design. The authors describe how such theranostic platforms, combining imaging with therapy, embody the spatiotemporal control over nanomaterial performance within pathophysiological microenvironments that the review identifies as a central design goal.

What distinguishes this synthesis is its insistence on connecting chemistry to clinical reality. The authors devote sustained attention to biosafety, examining how particle size, surface charge, protein corona formation, and degradation pathways determine biodistribution, organ accumulation, and clearance. They also confront the challenge of clinical scalability, noting that many spectacular results reported in the literature rely on synthesis routes that are difficult to reproduce at pharmaceutical manufacturing standards or on materials whose long-term toxicology remains incompletely characterized. Standardization of synthesis, rigorous batch-to-batch quality control, and translational toxicology emerge as prerequisites for the field’s next phase, and the review argues that interdisciplinary collaboration among chemists, materials scientists, biologists, and clinicians is the only realistic path from laboratory innovation to clinical practice.

The implications reach well beyond the imaging laboratory. Precision medicine depends on the ability to see disease early, characterize it molecularly, and monitor the response to therapy in real time, and synthetic nanoplatforms are increasingly the enabling technology for all three tasks. By establishing a theoretical foundation for the rational design of next-generation nanomaterials, the review by Lin and colleagues offers researchers a coherent framework for engineering probes whose behavior can be predicted from structure rather than discovered by trial and error. As the authors note, their hope is that this integrated perspective will inspire researchers across related fields and accelerate the translation of nanomaterial innovations into personalized healthcare management, a goal that now appears less like a distant aspiration and more like an engineering problem with a defined roadmap.

Subject of Research: Synthetic nanomaterial platforms for multiscale in vivo biomedical imaging

Article Title: Synthetic nanoplatforms for multiscale imaging in living organisms

Article References: Lin, F., Zhang, H., Zhan, J., Maimaitikelimu, X., Zhang, H., & Wang, H. (2026). Synthetic nanoplatforms for multiscale imaging in living organisms. Advanced Composites and Hybrid Materials. https://doi.org/10.1007/s42114-026-02055-4

Image Credits: AI Generated

DOI: 10.1007/s42114-026-02055-4

Keywords: nanomaterials, biomedical imaging, quantum dots, gold nanoparticles, aggregation-induced emission, iron oxide nanoparticles, nanobubbles, silica nanoparticles, carbon dots, surface functionalization, biosafety, precision medicine

The central idea is elegantly simple. Bacterial cell surfaces are studded with free primary amines, found at the N-termini of surface proteins and in lysine side chains, which are abundant across microbial taxa. The researchers exploited these native chemical handles using a hetero-bifunctional crosslinker called DBCO–sulfo–NHS. One end of this molecule, the sulfo-NHS ester, reacts with the surface amines under biocompatible aqueous conditions. The other end, a dibenzocyclooctyne group, remains available for a strain-promoted azide-alkyne cycloaddition, a bioorthogonal click reaction that specifically couples any molecule bearing an azide tag. This two-step design decouples the species-specific optimization of the surface reaction from the choice of the added functionality, meaning a single standardized protocol can be paired with fluorophores, enzymes, nucleic acids, or potentially any azide-containing compound.

The sulfo group on the NHS moiety proved critical. By enhancing the hydrophilicity of the crosslinker, it eliminated the need for organic solvents and reduced cellular internalization, both of which helped preserve cell viability. The team validated the approach on Escherichia coli, treating cells with a range of crosslinker concentrations from zero to 1000 milligrams per liter followed by an azide-modified Alexa Fluor 488 dye. Confocal microscopy showed bright, uniform surface fluorescence in fully treated cells, while controls lacking either the linker or the fluorophore showed no background signal, confirming that the reaction was specific rather than a product of nonspecific binding or autofluorescence.

Quantifying the trade-off between modification efficiency and cell survival was a key part of the study. Using flow cytometry alongside calibration curves built from fluorescent beads, the researchers converted fluorescence measurements into absolute numbers of molecules per cell. At the highest crosslinker concentration, roughly 210,000 molecules were tethered to each E. coli cell, corresponding to a surface density of about one molecule every 30 square nanometers, or a mean spacing of roughly five nanometers between adjacent molecules. Importantly, viability measured with the dead-cell stain SytoX Orange remained at 91 percent, and growth rates were indistinguishable from untreated controls. Only at extreme concentrations did cell death begin to rise, and even then the effect was modest.

Recognizing that membrane integrity alone does not capture the full picture of cellular health, the team also introduced a new standardized assay they call the regrowth dynamics assay. Rather than simply counting stained cells or colony-forming units, the method tracks the optical density of treated cultures over time, fits the curves to exponential or logistic growth models, and estimates the initial active population. Because cells that survive but lag in regrowth contribute less to the estimate, the assay is more stringent than conventional viability measures. Reassuringly, the regrowth-based estimates closely matched the dye-based ones, with 88 percent viability at the highest crosslinker dose, and neither method detected a significant departure from full viability at working concentrations.

To test universality, the researchers applied the protocol to five additional taxonomically diverse isolates: two aerobic marine Gram-negative strains, Vibrio splendidus and Neptunomonas sp.; the anaerobic gut bacterium Bacteroides ovatus; and two Gram-positive probiotic species from human stool, Lactococcus lactis and Lactobacillus rhamnosus. The anaerobic strains were functionalized under anaerobic conditions. Across all six organisms, the method tethered between 60,000 and 250,000 molecules per cell without significant viability losses or growth-rate changes. Gram-positive strains took up more molecules at a given crosslinker concentration but were also more sensitive to the treatment, a pattern the authors say reflects the distinct surface architectures of the two groups. Benchmarking against prior techniques made the advantages stark: metabolic labeling achieved at most a tenfold fluorescence increase compared with the 110-fold increase seen here, periodate-based oxidation dropped E. coli viability below 0.01 percent, and established biotin–sulfo–NHS protocols attached fewer than 4,000 molecules per cell versus 210,000 with the new crosslinker.

The practical power of the technique became clear in three demonstrations. First, cells coated with azide-modified beta-lactamase enzymes gained striking antibiotic resistance. In minimum inhibitory concentration assays, cells functionalized with 40 micromolar enzyme showed more than a 200-fold increase in ampicillin tolerance relative to untreated controls, with the effect scaling with enzyme dose. Even more striking, surface-bound enzymes outperformed the same enzymes free in solution, achieving equal or greater protection with tenfold fewer enzyme molecules. This spatial localization effect suggests that tethering catalytic machinery directly to the cell surface is a fundamentally efficient way to extend a microbe’s biochemical repertoire, with obvious implications for engineered probiotics that could survive antibiotic co-treatment.

Second, and perhaps most visually dramatic, the team used the method to program cell-to-cell adhesion with single-stranded DNA. Two populations of E. coli, each coated with a different 20-nucleotide azide-modified sequence, were mixed together. Complementary strands hybridized on contact, driving the cells to self-assemble into macroscopic aggregates visible within an hour. By fitting the sedimentation kinetics to a simplified aggregation model, the researchers calculated adhesion probabilities per cell encounter, which rose from a background of 0.2 percent to fifteen times that level at the highest DNA density. Non-complementary DNA controls showed no aggregation, confirming sequence specificity. Confocal imaging of red- and green-fluorescent populations revealed highly mixed aggregates, with 78 percent of nearest-neighbor pairs consisting of opposite-colored cells, well above the 50 percent expected from random assortment. Embedded in nutrient agar, the aggregates continued to grow, with cells dividing uniformly throughout the clusters.

The implications reach across biotechnology, medicine, and environmental engineering. Antibiotic-resistant probiotics could help maintain gut diversity during antibiotic treatment, a period when patients are vulnerable to infections such as Clostridioides difficile. Structured, DNA-programmed consortia could serve as seeding communities for microbiome modulation, biofilm engineering, and bioremediation, where spatially organized communities have been shown to remove pollutants more effectively. Because the method is purely chemical, it sidesteps the regulatory and ecological concerns surrounding genetically modified organisms, and it works on species that remain genetically intractable.

The approach does have limits. Some empirical optimization is still needed for each new species, since crosslinker sensitivity varied considerably between strains, and because nothing is genetically encoded, the modifications are temporary. Fluorescence measurements of dividing lineages showed that surface molecules are diluted by half with each cell division, so the longevity of any engineered phenotype depends on the cell’s growth rate and the density of molecules required for the function in question. Even so, the authors argue that the platform establishes a simple yet powerful framework for microbial surface engineering, one that decouples functional enhancement from genetic and metabolic constraints and opens the door to next-generation live therapeutics and synthetic microbial communities with capabilities their genomes never encoded.

Subject of Research: A universal chemical surface functionalization method for live microbial cells using hetero-bifunctional DBCO–sulfo–NHS crosslinkers

Article Title: A universal surface functionalization technique to chemically enhance live microbial cells

Article References: Vercelli, G. T., Zhou, X., Moreno-Gámez, S., Jeeda, R. R., Gregor, R., Słomka, J., Dagadu, A., Furst, A. L., & Cordero, O. X. (2026). A universal surface functionalization technique to chemically enhance live microbial cells. Molecular Systems Biology, 22(6), 962-978. https://doi.org/10.1038/s44320-026-00202-z

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DOI: 10.1038/s44320-026-00202-z

Keywords: surface functionalization, bacteria, click chemistry, DBCO, SPAAC, beta-lactamase, antibiotic resistance, DNA hybridization, cell adhesion, probiotics, synthetic biology, non-genetic engineering