The review, authored by Ashna Sureshkumar of the University of Virginia and Prakash Balu of Vels Institute of Science, Technology and Advanced Studies in Chennai, synthesizes in vivo preclinical studies published largely between 2020 and 2026 across oncology, central nervous system disease, and vascular medicine. Its unifying framework is unusual: rather than treating passive targeting, active targeting, and stimuli-responsive release as separate tricks, the authors evaluate them as components of a single, coordinated precision-control system operating across tissue, cellular, and subcellular scales. That framing matters, because the field’s most persistent failure mode has been stacking complexity without demonstrating that each added layer earns its keep.

The toolbox itself is diverse. Lipid-based systems, the oldest and most clinically validated family, use phospholipid bilayers roughly 50 to 300 nanometers in diameter to encapsulate both water-soluble and fat-soluble drugs, shielding them from degradation and extending circulation time. Polyethylene glycol coatings create so-called stealth formulations that evade immune surveillance and exploit the enhanced permeability and retention effect, the tendency of leaky tumor vasculature to admit and retain nanoparticles. Polymeric carriers built from biodegradable materials such as PLGA and chitosan, typically spanning 100 to 1,000 nanometers, offer tunable degradation kinetics that enable sustained release of small molecules, proteins, and genetic cargo. Inorganic nanostructures of gold, silica, and iron oxide, generally 10 to 100 nanometers, bring high surface area, structural stability, and built-in imaging or externally triggerable functions.

Perhaps the most striking recent development is the rise of biomimetic platforms. Engineered exosomes, natural extracellular vesicles measuring 30 to 150 nanometers, can cross biological barriers with low immunogenicity and can be decorated with antibodies or peptides to sharpen their targeting. Cell-membrane-coated nanoparticles borrow membranes from red blood cells or cancer cells to achieve immune escape and homotypic binding to matching tissue. Hybrid systems that fuse organic biocompatibility with inorganic functionality round out the portfolio. The review is candid that no single platform is superior: lipid and biodegradable polymeric carriers currently offer the most practical path to the clinic, while biomimetic and hybrid systems promise greater adaptability but struggle with standardization, since variability in cellular source, isolation, and cargo loading complicates reproducible manufacturing.

The targeting story is more sobering than the field’s enthusiasm might suggest. Passive targeting via the enhanced permeability and retention effect has long been the foundational assumption of cancer nanomedicine, but the review highlights clinical imaging data showing just how unreliable it is. In patients with metastatic HER2-positive breast cancer, radiolabeled liposomal nanoparticles accumulated in tumors with roughly 35-fold variation between patients, while substantial uptake appeared in clearance organs such as the liver and spleen. More provocatively, recent experimental work in mouse models and human tumor samples challenges the textbook view that nanoparticles enter tumors mainly through passive gaps between endothelial cells, implicating active transendothelial transport as a major route. The authors conclude that EPR-based accumulation should not be treated as a universal feature of solid tumors, and they call for imaging biomarkers to identify patients whose tumors are actually amenable to nanoparticle delivery.

Active targeting, meanwhile, delivers a subtler lesson. Ligands such as folate, transferrin-binding peptides, integrin binders, and monoclonal antibodies reliably increase receptor-mediated internalization once a carrier reaches its target cell. But a landmark comparison of HER2-targeted immunoliposomes against otherwise identical nontargeted liposomes found that antibody targeting increased tumor cell internalization without increasing total tumor localization. In other words, active targeting sharpens the last step of delivery without fixing the first. Stimuli-responsive systems, which hold cargo stable in circulation and release it in response to acidic pH around 6.5 to 6.9, elevated glutathione, protease activity, or external triggers like light, ultrasound, and magnetic fields, add temporal control, though the review notes that inconsistent trigger conditions in vivo can produce uneven activation.

Where the precision paradigm genuinely shines is in the newest wave of preclinical studies. A theranostic nanoparticle just over 8 nanometers across, carrying gadolinium and bismuth chelates with MRI and radiosensitizing functions and decorated with cRGD peptides targeting lung cancer integrins, produced delayed tumor growth, complete regression in some mice, prolonged survival, and increased infiltration of CD3-positive and CD8-positive T cells with no evident systemic toxicity. A carrier-free peptide-drug nanoparticle combining doxorubicin with an immune adjuvant, guided by an iRGD tumor-homing peptide and an MMP-2-responsive linker, nearly eliminated visible lung metastases in a melanoma model and synergized with immune checkpoint inhibition. Most dramatically, a platelet-hitchhiking polymer conjugate carrying the vascular-disrupting agent DMXAA achieved 2.61-fold greater tumor accumulation than its non-platelet counterpart and an 89.1 percent tumor-suppression rate in colorectal cancer mice, exploiting the natural adhesion of platelets to exposed collagen in tumor vasculature for self-amplifying targeting.

The central nervous system results may be the most consequential for patients. The blood-brain barrier blocks nearly all large-molecule and most small-molecule drugs, and nanocarriers offer one of the few credible routes through it. In one standout study, lipid nanoparticles modified with an ITP peptide that allosterically binds the insulin receptor’s transmembrane domain delivered siRNA against BACE1, an Alzheimer’s-related enzyme, across the barrier in APP/PS1 transgenic mice. After seven tail-vein injections, the treated animals showed improved novel-object-recognition and Morris-water-maze performance, and BACE1 expression in the hippocampus and cortex fell to levels comparable with wild-type controls, without organ toxicity or inflammatory cytokine responses. In vascular disease, a monocyte-membrane-coated nanoghost carrying the anti-diabetic drug gliclazide homed to inflamed endothelium in atherosclerotic rabbits, cutting CD14-positive macrophage abundance in aortic plaques from nearly 47 percent to 7.7 percent, while a platelet-anchored, ROS-responsive protein nanoassembly shrank aortic plaque area 5.82-fold in ApoE-deficient mice.

Yet the review refuses to let enthusiasm outrun evidence. Most oncology studies rely on murine xenograft models with exaggerated EPR effects and simplified immune systems, which may systematically overestimate nanocarrier accumulation in humans. CNS work is constrained by short treatment durations and barrier models that ignore age-related and inflammatory heterogeneity. Vascular targeting benefits from directly accessible endothelial targets but contends with blood flow, shear stress, and rapid clearance. The authors also point to a cautionary tale from the clinic: MM-302, a HER2-targeted liposomal doxorubicin that looked compelling preclinically, saw its randomized HERMIONE trial terminated after a futility analysis indicated it was unlikely to beat standard therapy. Clinically approved successes such as Doxil, Abraxane, and the siRNA therapy Onpattro prove nanocarriers can reach patients, but they achieved that through altered drug disposition and reproducible manufacturing rather than ever-more-elaborate targeting.

The path forward, the review argues, lies in disciplined pragmatism rather than maximal complexity. Artificial intelligence and machine learning are increasingly used to tune nanoparticle size, composition, and surface chemistry against biodistribution and toxicity data, while humanized disease models and organ-on-chip platforms promise more predictive evaluation under physiologically relevant flow. The authors call for standardized characterization and minimum reporting requirements, appropriate free-drug and nontargeted controls in every study, quantitative biodistribution measurements, long-term safety assessment, and quality-by-design manufacturing under Good Manufacturing Practice conditions. The bottom line is bracing: precision-controlled nanomedicine is preclinically feasible and increasingly spectacular in animal models, but the systems most likely to reach patients may be the simpler ones, those that demonstrate measurable benefit over a plain nontargeted carrier, predictable clearance, and batch-to-batch reproducibility. In a field intoxicated by multifunctional design, the most radical idea may be knowing when to stop adding features.

Subject of Research: Preclinical advances in precision-controlled targeted drug delivery using nanomedicine platforms

Article Title: Innovative nanomedicine strategies for precision-controlled targeted drug delivery: recent preclinical progress

Article References: Sureshkumar, A., & Balu, P. (2026). Innovative nanomedicine strategies for precision-controlled targeted drug delivery: recent preclinical progress. Frontiers in Biomaterials Science, 5, Article 1916503. https://doi.org/10.3389/fbiom.2026.1916503

Image Credits: AI Generated

DOI: 10.3389/fbiom.2026.1916503

Keywords: nanomedicine, targeted drug delivery, nanoparticles, liposomes, EPR effect, stimuli-responsive release, blood-brain barrier, theranostics, biomimetic nanocarriers, preclinical studies, precision medicine, drug delivery

The review, led by Xinwei Li, Haonan Zhang, Ruidong Ding, and Feng Wang at the Affiliated Hospital of Qingdao University and the University of Chinese Academy of Sciences, systematically dissects what the term “precision” should actually mean when applied to framework-based nanomedicine. Drawing on approximately 1,200 records identified through PubMed, Web of Science, Scopus, and Crossref, from which roughly 150 primary studies and reviews were retained, the authors construct a five-dimensional definition of precision delivery: material, spatial, temporal, mechanistic, and translational. Each dimension carries a distinct evidentiary burden, and failure at any single stage can erase an advantage established at another.

The distinction matters because the biological reality of drug delivery is unforgiving. Landmark analyses have shown that only a median of roughly 0.7 percent of an injected nanoparticle dose reaches solid tumors, and that delivery efficiency is governed more by biological barriers—dilution, protein adsorption, immune clearance, vascular endothelium, and the mononuclear phagocyte system—than by material performance in buffered solution. A particle may load a drug efficiently yet release it prematurely in plasma. It may accumulate in a tumor while remaining trapped inside stromal phagocytes. It may enter target cells without ever releasing functional macromolecular cargo. These failure modes are invisible to the metrics most commonly reported in the literature.

MOFs and COFs approach the problem from complementary directions. MOFs are built from metal ions or clusters connected by multidentate organic linkers, and their coordination chemistry offers a tunable balance between stability and degradability. Zirconium frameworks such as UiO-66, with their strong Zr(IV)–carboxylate bonds, resist hydrolysis; zinc-based ZIF-8 remains stable near physiological pH but dissolves once imidazolate linkers are protonated in acidic endosomal compartments; iron-carboxylate MIL frameworks are designed for biodegradation; and cyclodextrin MOFs coordinate potassium with γ-cyclodextrin to form bioabsorbable carriers. COFs, by contrast, are constructed entirely from organic building blocks joined by covalent linkages, offering metal-free or metal-sparse backbones, conjugated pore walls capable of light harvesting, and a stability hierarchy that runs from labile boronate esters through imines and hydrazones to robust β-ketoenamine, imide, and sp²-carbon linkages.

Neither family is intrinsically more precise. The review argues that precision emerges only from matching the framework to the cargo, the route of administration, the biological barrier, and the intended pharmacology. MOFs may be favored when coordination chemistry, metal-center catalysis, or metal-associated imaging is essential. COFs may be favored when a metal-free pore environment, covalently encoded trigger chemistry, or tunable aromatic interactions is the decisive function. Hybrids—MOF-on-MOF, MOF@COF, COF@MOF, or membrane- and vesicle-coated composites—are justified only when the interface creates a measurable gain that a single framework or simpler carrier cannot provide.

The cargo itself introduces further complexity. Small molecules can enter framework pores and interact through hydrophobic forces, hydrogen bonding, electrostatics, π-stacking, or coordination, but high loading is not the design endpoint; the goal is an affinity window that suppresses leakage during transit while permitting pharmacologically useful release at the target site. Proteins, enzymes, and nucleic acids pose a separate challenge because their dimensions, conformational integrity, and functional compartment matter. Biomimetic mineralization—growing a MOF shell around a macromolecule—can protect cargo under mild aqueous conditions, but high encapsulation efficiency does not guarantee retained activity, and fluorescent uptake does not establish cytosolic release. Therapeutic gases such as nitric oxide, carbon monoxide, and hydrogen sulfide require local concentration–time control because their effects are highly dose- and context-dependent, and gas adsorption measured under high pressure is not equivalent to a useful dose in hydrated tissue.

Spatial precision demands more than a targeting ligand. The review emphasizes that whole-organ fluorescence supports organ-associated signal, not intact-particle delivery to a specific cell type. Cell uptake does not establish cytosolic release, and intracellular localization does not establish functional protein, RNA, or enzyme activity. A convincing targeting study should report blood exposure, whole-organ distribution, tumor concentration, cell-type distribution within the tumor, and competition or receptor-loss controls. Active ligands typically improve cellular binding and internalization more reliably than they increase the fraction of injected dose reaching a tumor, and changes in formulation can alter pharmacokinetics independently of receptor recognition.

Temporal precision is equally demanding. Acid-triggered disassembly is the most common release mechanism, but many studies compare pH 7.4 with pH 5.0 in salt-poor buffers, whereas extracellular tumor pH is typically only moderately acidic (about 6.5–6.8) and protein-rich, while endosomal and lysosomal compartments reach roughly pH 4.5–5.5 only after cellular uptake. Redox-responsive systems exploit elevated intracellular glutathione or disease-associated reactive oxygen species, but the biological matrix introduces confounders: millimolar glutathione scavenges ROS generated by oxidase- and peroxidase-like nanozymes, protein coronas can physically block catalytic sites, and physiological ionic strength alters metal coordination. Externally applied energy—light, ultrasound, magnetic fields—provides spatial focusing, but strong effects in superficial xenografts do not necessarily translate to deep or disseminated disease, and the energy field and carrier distribution must overlap at the required scale.

The translational dimension is where the field faces its steepest climb. As of the literature search date, no MOF- or COF-based drug product has received marketing approval, although early clinical translation has begun with hafnium-based nanoscale MOF radiosensitizers. RiMO-301 completed a Phase 1 dose-escalation trial combining intratumoral injection with palliative radiation in advanced tumors, and is now being evaluated in a Phase 1b/2a trial for head-and-neck cancer. A related candidate, RiMO-401, entered a Phase 1 trial but was terminated owing to slow enrolment. For most framework candidates, safety discussions still rest on preclinical evidence, and the review stresses that a short viability assay establishes only an initial concentration range. A development-oriented package should include haemocompatibility, complement and cytokine responses, immunogenicity, genotoxicity, repeat-dose exposure, and organ-specific endpoints determined by actual biodistribution.

Manufacturing adds another layer of difficulty. Many MOFs and COFs are prepared in dilute solvothermal batches using high-boiling organic solvents, and particle size, defect density, and residual solvent can drift between batches when mixing, heating, and cooling rates are not tightly controlled. Continuous-flow synthesis offers tighter residence-time and temperature control, while green or aqueous solvent systems reduce the downstream purification burden. Activation and drying are not trivial steps: the porosity that underpins loading capacity depends sensitively on solvent exchange and thermal or supercritical treatment, and incomplete activation leaves residual solvent in the pores that reduces usable capacity. Sterilization and storage are often deferred until late development, yet filtration may be impossible for larger particles, and heat, irradiation, or chemical sterilants can change frameworks, linkers, drugs, and biological coatings in unpredictable ways.

The review’s most consequential contribution is its claim-to-evidence mapping, which converts “precision” from an aspirational label into a set of testable criteria. A targeted delivery claim requires quantitative target-cell exposure at the stated resolution, not organ fluorescence. A functional macromolecule delivery claim requires sequence-, activity-, or rescue-based endpoints, not fluorescent uptake. A biodegradable carrier claim requires identification and time-resolved disappearance of the intact framework plus the fate of its fragments, not merely loss of crystallinity in buffer. A synergistic therapy claim requires dose- or exposure-matched interaction analysis, not simply a combination that outperforms either component alone. A theranostic claim requires that the diagnostic output inform localization, activation, response, or dosing, not merely that the particle happen to be fluorescent.

The authors also confront the field’s tendency toward conceptual overreach. A large Brunauer–Emmett–Teller surface area measured on an activated powder does not directly predict usable loading in a hydrated nanosuspension. The word “biocompatible” is frequently assigned after short-term viability or histology experiments, even though framework degradation can generate metal ions, ligands, fragments, and re-coordinated species with distinct kinetics and toxicological profiles. Nutritional familiarity with a free element cannot establish the safety of the corresponding framework. A precision claim must therefore be evaluated at the level of the complete product and its transformation over time, not inferred from the reputation of an individual building block.

Beyond conventional tumor models, the review highlights metabolic and fibrotic diseases as more stringent tests of precision. These conditions involve diffuse tissue, chronic dosing, multiple cell populations, and disease-dependent changes in receptor expression, redox state, and extracellular matrix. The authors’ own preclinical program illustrates the approach: a MOF-818-based nanozyme modified with an ASGR1 antibody and loaded with uridine diphosphate glucose coordinated antioxidant catalysis, lipid efflux, and suppression of lipogenesis in models of metabolic dysfunction-associated steatotic liver disease. A related anti-ASGR1 nanocomplex combined a MIL-family core with thyroid hormone for rapid reduction of donor-liver steatosis, including evaluation in transplantation-associated perfusion. A MOF-engineered exosome system encapsulated exosomes with copper-cysteine nanozyme activity in a ZIF-containing architecture and reported preclinical benefit across lung, liver, and kidney fibrosis models. These remain preclinical findings, and the authors are explicit that they do not demonstrate human pharmacokinetics, transplant benefit, or chronic safety.

Local delivery offers a practical translation route for complex frameworks because it limits systemic exposure and permits high concentrations at an accessible site. Wound dressings, injectable gels, coatings, and microneedles can retain MOFs or COFs while allowing drugs, ions, or catalytic products to diffuse. A bimetallic MOF nanozyme composite for diabetic wound management combined wearable glucose sensing with microenvironment-dependent catalytic treatment, illustrating a closed-loop concept in which a disease biomarker is measured and the same material family contributes to therapy. The authors caution, however, that a true closed loop would require the sensor output to alter dose or activation in real time; parallel sensing and treatment is an important step but not yet autonomous feedback control.

The review closes with a set of design rules that prioritize simplicity and accountability over architectural ambition. Begin with a delivery bottleneck, not a framework. Define the active entity and its dose. Couple cargo affinity to the intended release pathway. Measure precision at the claimed spatial scale. Treat the biological interface as a dynamic component. Separate trigger response from framework degradation. Build safety and manufacturability into candidate selection. Publish negative results. Test precision against a simpler benchmark. A framework that achieves similar efficacy with a lower dose, wider safety margin, uniquely protected cargo, or controllable activation has a defensible value proposition; a framework that only increases loading relative to an unoptimized comparator does not. Under this discipline, MOFs and COFs can evolve from impressive porous materials into accountable drug products whose chemical programmability is matched by pharmacological and manufacturing precision.

Subject of Research: Precision drug delivery using metal-organic and covalent organic frameworks

Article Title: Metal-organic and covalent organic frameworks for precision drug delivery: a precision-by-design evidence framework for biologically accountable nanomedicine

Article References: Li, X., Zhang, H., Ding, R., & Wang, F. (2026). Metal-organic and covalent organic frameworks for precision drug delivery: a precision-by-design evidence framework for biologically accountable nanomedicine. Frontiers in Drug Delivery, 6, Article 1970554. https://doi.org/10.3389/fddev.2026.1970554

Image Credits: AI Generated

DOI: 10.3389/fddev.2026.1970554

Keywords: metal-organic frameworks, covalent organic frameworks, precision drug delivery, nanomedicine, stimuli-responsive release, nanozymes, theranostics, biomimetic coatings, biodegradable carriers, drug delivery barriers, quality by design, translational nanomedicine

What separates magnetic nanorobots from the nanoparticles that already populate cancer nanomedicine is agency. Conventional nanocarriers, including approved formulations such as the albumin-bound paclitaxel particle Abraxane, are essentially passive: they drift with blood flow, rely on the leaky vasculature of tumors for passive accumulation through the enhanced permeability and retention effect, or depend on surface ligands to find their targets. MNRs, by contrast, are active machines. Driven by rotating or oscillating magnetic fields that penetrate biological fluids without fuel or chemical propellants, they propel, rotate, swarm, and reconfigure on command. Beyond navigation, they can perform physical work, perforating cell membranes, penetrating tissue, and applying mechanical force, moving nanomedicine from passive delivery toward active intervention and manipulation inside the body.

The review traces how these machines are built, distinguishing two fabrication philosophies. Top-down approaches, including photolithography, two-photon polymerization, focused ion beam milling, and electron beam lithography, carve precise three-dimensional structures out of larger materials, with electron beam methods reaching sub-10-nanometer resolution at high cost. Bottom-up approaches, such as self-assembly, chemical vapor deposition, DNA origami, and wet chemical synthesis, build devices molecule by molecule, offering atomic-level compositional control and the ability to embed bioactive ligands like polyethylene glycol directly during synthesis. Increasingly, researchers combine both: a top-down structural chassis provides geometric precision, while bottom-up chemistry supplies magnetic nanoparticles, drug payloads, and targeting ligands, integrated through microfluidics or surface chemistry. The synthesis route, the authors emphasize, ultimately governs magnetic responsiveness, drug-loading capacity, and degradation kinetics.

Shape determines how these robots swim. The review classifies MNRs into five families: spherical robots that roll or slide through fluids; helical robots inspired by bacterial flagella that convert rotation into corkscrew thrust in low-Reynolds-number liquids; flexible robots that deform to squeeze through narrow passages, such as artificial flagella built from red blood cells linked by DNA hinges; wire-like robots fabricated by template-assisted electrochemical deposition that navigate complex environments; and biohybrid robots that fuse living or biological components with magnetic materials. One striking example uses Spirulina, a spiral-shaped microorganism, as a natural template coated with iron oxide nanoparticles, producing a magnetically steerable robot that carries anticancer drugs and doubles as a photothermal therapy platform. Locomotion strategies mirror this diversity, spanning corkscrew propulsion, traveling-wave and ciliary-stroke motion, and surface-assisted rolling along vessel walls.

The most clinically consequential capability may be on-demand drug release. The review catalogs a growing arsenal of stimuli-responsive designs that promise zero leakage, rapid response, and release only at the tumor site. Near-infrared light triggers drug liberation from chitosan-based hollow magnetic nanocarriers loaded with doxorubicin, which weaken drug-binding electrostatic interactions under irradiation while generating local heat. The acidic tumor microenvironment, a byproduct of intensified glycolysis in hypoxic tumors, cleaves pH-sensitive bonds in other designs. Some robots exploit biochemistry itself: zinc-based cystine microrobots self-destruct inside prostate cancer cells when the intracellular reducing environment degrades their amino acid scaffold, releasing therapeutic zinc ions, while bismuth-based tubular robots achieve ultrafast release through electrochemical reduction. Machine learning is now entering the design loop, with physics-informed neural networks achieving high prediction accuracy for pH-triggered release kinetics across physiological conditions.

Biohybrid systems push biocompatibility further by borrowing from nature outright. Chlorella, a single-celled microalgae smaller than a human red blood cell, has been magnetized, loaded with doxorubicin, and assembled into chains through dynamic magnetic self-assembly, yielding microrobots with strong propulsion at low Reynolds numbers and pH-responsive release. Amoeba-inspired nanorobots made of deformable polyphosphoester squeeze from blood vessels deep into tumor tissue before releasing their cargo under an alternating magnetic field. A two-stage marsupial system for glioblastoma sends a mother robot across the blood-brain barrier, from which child robots deploy for precise secondary targeting within the brain. Even the cell membrane itself has become a target: gold nanorods coated with nickel and titanium layers mechanically agitate cancer cell membranes under magnetic rotation, opening transient pores that admit drugs directly.

MNRs are also being engineered to remodel the tumor microenvironment rather than merely survive it. Enzymatic cascade robots co-loading lactate oxidase and catalase consume lactate to relieve tumor acidity while generating oxygen bubbles that propel them deeper into tissue, simultaneously easing the hypoxia that drives malignancy. Macrophage-focused designs exploit the fact that surface topography influences immune cell polarization: nanoscale-smooth magnetic robots push macrophages toward the anti-tumor M1 phenotype, M1-membrane-coated photothermal nanocomplexes home to tumors naturally, and magnetized living macrophages loaded with doxorubicin and indocyanine green act as controllable cellular robots. A magnetically driven calcium carbonate robot neutralizes tumor acidity while restoring dendritic cell activity, promoting cross-presentation of antigens and triggering cellular immune responses against the tumor.

Therapeutically, the two dominant modalities are photothermal therapy, in which magnetic navigation delivers photothermal agents that convert near-infrared light into lethal local heat, and chemodynamic therapy, which exploits the tumor’s own hydrogen peroxide through Fenton reactions catalyzed by iron, copper, or manganese ions to generate cell-killing hydroxyl radicals. Combination platforms are multiplying: a biomimetic nanorobot cloaked in a platelet and M1 macrophage hybrid membrane crosses the blood-brain barrier and combines photothermal therapy, chemodynamic therapy, temozolomide chemotherapy, and PD-L1 immune checkpoint blockade against glioblastoma. Heater-thermometer nanorobot clusters now provide feedback-controlled hyperthermia, using their own color changes to regulate irradiation with high spatiotemporal precision and avoid the collateral damage of overheating.

Clinical translation remains the hardest step, and the review is candid about the gap. No true magnetic nanorobot has yet entered clinical trials, though related nanotechnologies offer encouraging precedents, from gold nanoshell ablation trials to MRI-guided gadolinium nanoparticle radiosensitization and ferumoxytol imaging. Preclinical milestones are nonetheless striking: a clinically ready magnetic microrobot platform has navigated the vascular networks of pigs and sheep, achieving up to 95 percent delivery success in flowing vessels, and an algorithm-guided magnetic resonance navigation system multiplied the number of microrobots reaching targeted liver lobes in patient simulations. The obstacles ahead include the protein corona that rewrites a nanorobot’s biological identity in blood, batch-to-batch manufacturing variability, sterilization complexity, ambiguous regulatory status as combination drug-device products, and the absence of any single imaging modality adequate for real-time tracking. The authors see artificial intelligence as the integrating force ahead, from reinforcement learning-based navigation to deep learning reconstruction of three-dimensional robot positions from two-dimensional MRI, pointing toward closed-loop, perception-decision-execution systems that could finally turn laboratory promise into hospital-bed reality.

Subject of Research: Magnetic nanorobots for targeted cancer drug delivery and theranostics

Article Title: Magnetic nanorobots in oncology: From targeted drug delivery to smart theranostic systems

Article References: Liu, X., Li, C., Xu, Z., Yan, Y., Liu, W., Li, Y., & Gao, M. (2026). Magnetic nanorobots in oncology: From targeted drug delivery to smart theranostic systems. Materials Today Bio, 41, Article 103709. https://doi.org/10.1016/j.mtbio.2026.103709

Image Credits: AI Generated

DOI: 10.1016/j.mtbio.2026.103709

Keywords: magnetic nanorobots, targeted drug delivery, cancer therapy, photothermal therapy, chemodynamic therapy, tumor microenvironment, biohybrid microrobots, stimuli-responsive release, nanomedicine, clinical translation, artificial intelligence, theranostics

The core problem the review identifies is not a shortage of drugs but a failure of delivery. In urinary tract infection, uropathogenic Escherichia coli adheres to the bladder lining through adhesins such as FimH, invades epithelial cells and builds intracellular bacterial communities that shelter it from antibiotics and immune attack. Catheter-associated infections add another layer: proteins from urine rapidly coat the device surface, forming a conditioning film on which pathogens such as Enterococcus faecalis construct mature biofilms whose extracellular matrix blocks drug diffusion and harbors metabolically quiescent bacteria. Meanwhile, continuous urine washout, cyclic bladder filling and emptying, and the urothelial mucus barrier strip away free drugs before they can act. For interstitial cystitis and chronic prostatitis, the barriers are anatomical: the prostatic capsule, epithelial tight junctions and local microcirculation restrict penetration, while heterogeneous, multifactorial pathology limits oral medications to symptomatic relief.

Nanoparticles attack these bottlenecks through tunable physics. By adjusting particle size, surface charge, material composition and surface ligands, researchers can boost drug loading, prolong local retention, enhance tissue penetration and program controlled release. The review divides the relevant platforms into three classes. Organic nanoparticles, including liposomes, polymeric particles, dendrimers and chitosan, offer biocompatibility, biodegradability and flexible loading, making them well suited to intravesical instillation, mucosal adhesion and delivery of proteins or nucleic acids. Inorganic nanoparticles, such as silver, gold, copper and zinc oxide particles and mesoporous silica, bring intrinsic antibacterial, antioxidant, photothermal or imaging capabilities that do not depend on traditional antibiotic targets. Hybrid systems combine the two, integrating drug delivery, contact killing, anti-adhesive surfaces and sustained release within a single construct.

For recurrent urinary tract infection, the most striking advance targets bacteria hiding inside bladder cells. Tetracycline loaded onto bovine serum albumin-coated nanodiamonds was taken up by urothelial cells, colocalized with intracellular UPEC and released its cargo in acidic endosomes, enhancing bacterial clearance, reducing bladder inflammation and shrinking residual intracellular bacterial communities in infected bladders. Elsewhere, rosemary-oil-loaded chitosan nanophytosomes boosted antibacterial and antibiofilm activity against multidrug-resistant E. coli while easing tissue injury, and liposomes have been shown to protect piperacillin from destruction by staphylococcal beta-lactamase, preserving activity against enzyme-mediated resistance. Ciprofloxacin carried in albumin nanoparticles retained anti-UPEC activity with reduced toxicity to bladder cells and greater effect against mature biofilms than the free drug.

Inorganic nanomaterials bring multimodal killing mechanisms to the fight. Silver nanoparticles release silver ions, generate reactive oxygen species, disrupt membranes and interfere with DNA replication, retaining activity against many drug-resistant strains. Green-synthesized silver particles derived from betel-leaf extract have been shown to silence quorum-sensing systems in Serratia marcescens and Proteus mirabilis, downregulating virulence and biofilm genes. Combining silver nanoparticles with ampicillin or amikacin produced synergistic effects against multidrug-resistant uropathogens at concentrations with low toxicity to human fibroblasts. Zinc oxide nanoparticles inhibited adhesion of fluconazole-resistant Candida albicans by downregulating the ALS1 and ALS3 genes, while silica-tannase nanoconjugates outperformed conventional antibiotics against common urinary pathogens in vitro.

Catheter-associated infection has emerged as the clearest engineering application. A dual-layer nanoengineered catheter deposited silver nanoparticles on silicone and capped them with porous zinc, which regulated ion release, curbed burst effects and, through zinc-mediated reactive oxygen generation, blocked early bacterial adhesion; in a rabbit model it reduced biofilm, encrustation, urethral inflammation and epithelial injury. Beta-casein-capped hollow chitosan nanospheres co-loading a quorum-sensing inhibitor and a bactericide released their payloads sequentially in response to bacterial proteases, suppressing biofilm formation by more than 95 percent and preventing catheter occlusion for 30 days in artificial urine flow. Gold nanoshells immobilized on silicone generated localized heat under near-infrared irradiation, eradicating adherent drug-resistant E. faecalis, while zinc-doped copper oxide coatings delayed the onset of catheter-associated infection in rabbits, with some animals remaining infection-free throughout a seven-day experiment.

Hybrid and biomimetic coatings push the concept further. A superhydrophobic polydopamine-silver-perfluorinated multilayer on silicone catheters combined reduced bacterial contact, delayed biofilm formation and sustained silver release, extending the time to catheter obstruction from roughly 40 hours to about 100 hours. A nanozyme hydrogel built from gold and iron co-doped silver peroxide paired peroxidase-like catalytic hydroxyl radical generation with catalase-like oxygen production, adding anti-inflammatory and microenvironmental modulation to antibacterial action. Biodegradable ureteral stents embedded with silver-gold core-shell nanoparticles created a constantly renewing contact-killing surface that reduced stent-associated infection in a porcine model, illustrating how device interfaces can be engineered for long-term protection.

For noninfectious disease, the emphasis shifts from killing bacteria to repairing barriers and calming chronic inflammation. Thiolated chitosan nanoparticles formed disulfide bonds with bladder mucosal glycoproteins, achieving roughly 14-fold greater adhesion than unmodified particles under urine washout. Cationic liposomes delivered nerve growth factor antisense oligonucleotides to the urothelium with about 40-fold higher uptake than free oligonucleotides, normalizing voiding frequency in a rat model of interstitial cystitis. Hyaluronic acid-based self-assembled nanosheets replenished the damaged glycosaminoglycan layer and reduced bladder inflammation, while curcumin-loaded cerium oxide nanoparticles exploited the reversible cerium redox cycle to scavenge reactive oxygen species, easing pain and restoring urothelial integrity in mice. A nerve-growth-factor-targeting nanocluster-antibody-drug conjugate even combined lesion targeting, fluorescence and CT imaging and immunomodulatory drug release, outperforming standard intravesical therapies in preclinical models.

Chronic prostatitis/chronic pelvic pain syndrome illustrates the precision potential most vividly. Folate-modified, oxidation-responsive nanoparticles loaded with cefpodoxime proxetel homed to folate receptors on activated macrophages in inflamed prostatic tissue, released antibiotic in the reactive-oxygen-rich environment while consuming excess radicals, and reduced bacterial burden, inflammatory cytokines and pelvic pain sensitization in mice. A pH and ROS dual-responsive dexamethasone nanoformulation accumulated in prostatic tissue, attenuated pelvic pain hypersensitivity and was associated with reduced depression-like behavior. Antigen-coupled PLGA nanoparticles carrying a TRPM8-derived peptide induced immune tolerance, raising pain thresholds and lowering inflammatory markers, a strategy fundamentally distinct from conventional analgesia.

The authors are careful to temper enthusiasm with translational reality. Most evidence remains confined to cell cultures and short-term animal studies whose models poorly capture chronicity, recurrence and patient heterogeneity. Long-term safety questions loom large, particularly for metal-based nanomaterials where the window between bacterial killing and urothelial injury must be defined, and for biomimetic systems where donor variability complicates quality control. Manufacturing scale-up, batch consistency, storage stability and premature drug leakage all demand systematic standards. Yet the trajectory is clear: from simple antibiotic carriers toward multifunctional, stimuli-responsive, phenotype-matched platforms that could one day pair with antibiotics, behavioral therapy and neuromodulation as components of individualized care for some of urology’s most persistent inflammatory diseases.

Subject of Research: Nanoparticle-based therapeutic platforms for inflammatory disorders of the urinary system, including urinary tract infection, catheter-associated infection, interstitial cystitis/bladder pain syndrome and chronic prostatitis/chronic pelvic pain syndrome

Article Title: Nanoparticle-based therapeutic platforms for inflammatory disorders of the urinary system: Engineering local delivery, biointerface regulation, and smart responsive therapy

Article References: Wang, W., Ma, J., Hou, C., Chen, J., & Ni, K. (2026). Nanoparticle-based therapeutic platforms for inflammatory disorders of the urinary system: Engineering local delivery, biointerface regulation, and smart responsive therapy. Materials Today Bio, 41, Article 103673. https://doi.org/10.1016/j.mtbio.2026.103673

Image Credits: AI Generated

DOI: 10.1016/j.mtbio.2026.103673

Keywords: nanoparticles, urinary tract infection, catheter-associated UTI, interstitial cystitis, chronic prostatitis, biofilms, drug delivery, silver nanoparticles, stimuli-responsive release, intravesical therapy, antimicrobial resistance, nanomedicine

The appeal of MOFs begins with their architecture. Metal centers or clusters act as nodes, joined by organic linkers into extended three-dimensional crystalline networks whose pores can be adjusted with near-atomic precision. Because researchers can independently vary the metal, the linker and the functional groups decorating the pore walls, MOFs offer record-breaking internal surface areas, tunable pore sizes and a modular versatility that rigid inorganic adsorbents such as zeolites struggle to match. The review categorizes frameworks into rigid structures suited to molecular sieving, flexible or breathing frameworks whose unit cells expand and contract as guest molecules enter and leave, and surface-functionalized frameworks grafted with groups such as amines, sulfonates or carboxylates that dramatically alter adsorption affinity, hydrophobicity and stability. Open metal sites, generated when coordinated solvent molecules are stripped away during activation, add another handle for tuning performance; the copper framework HKUST-1, for example, adsorbs notably more carbon dioxide in the presence of a small amount of water.

A substantial portion of the review is devoted to how these materials are actually made, because the synthesis route shapes everything from crystallinity to cost. Solvothermal and hydrothermal methods remain the workhorses, producing highly crystalline frameworks such as MIL-101(Cr) and UiO-66, but they demand high temperatures and pressures, large volumes of organic solvents and long reaction times that limit scalability. Microwave-assisted synthesis slashes reaction times and yields uniform nanocrystals with high phase purity, yet scaling microwave equipment to industrial throughput is difficult. Sonochemistry accelerates nucleation with cavitation bubbles that momentarily reach thousands of kelvin, producing nanoscale MOFs with high surface areas, though controlling particle size distribution remains a challenge. Mechanochemical routes grind metal salts and linkers together in ball mills with little or no solvent, offering a genuinely green option at room temperature, at the cost of somewhat lower crystallinity. Electrochemical synthesis, first used by BASF to make HKUST-1 in 2005, supplies metal ions through anodic dissolution of a metal electrode, avoiding corrosive counterions and enabling continuous production. The authors conclude that no method is universally ideal: high crystallinity and tunability favor solvothermal chemistry, while green scalability increasingly points toward mechanochemical and continuous-flow techniques.

In the environmental arena, the review highlights MOFs as adsorbents and catalytic degradation platforms for three major classes of pollutants: synthetic dyes, heavy metals and emerging contaminants. Dye pollution is a serious concern because many residual dyes are carcinogenic and persist in water systems. Frameworks from the UiO, ZIF and MIL families, along with their composites, capture both cationic dyes such as methylene blue, rhodamine B and malachite green and anionic dyes such as methyl orange and congo red. The removal mechanisms operate in synergy: electrostatic attraction between oppositely charged dye molecules and framework surfaces, pi–pi stacking between the aromatic rings of dyes and the organic linkers, hydrogen bonding between surface functional groups and dye molecules, and size-selective pore filling. Because the surface charge of a MOF depends on solution pH and the functional groups present, researchers can engineer adsorbents that switch selectivity simply by decorating the pore walls.

Heavy metals present an even sterner test because they are non-biodegradable and toxic at low concentrations. MOFs bind Pb(II), Cr(VI), As(III/V) and Hg(II) through a combination of ion exchange, surface complexation, chelation, electrostatic interaction and redox conversion. Functionalization with thiol or amine groups markedly boosts selectivity for soft, highly toxic ions such as Hg(II), while redox-active iron-based frameworks can reduce toxic Cr(VI) to the far less hazardous Cr(III), coupling detoxification with immobilization. The review also emphasizes MOF-based membranes, formed when MOF crystals self-assemble on porous supports, which combine tunable pore sizes with high selectivity and recyclability for continuous water purification. The trade-offs are candidly acknowledged: MIL-101(Cr) offers enormous mesoporous cages that handle bulky dye and pharmaceutical molecules, but zirconium-based UiO-66 provides superior chemical robustness, and ZIF-8 resists water yet suffers from narrow pore apertures that restrict diffusion of large contaminants.

The second half of the review turns to biomedicine, where the requirements are far stricter than in industrial applications. An effective MOF drug carrier must encapsulate therapeutics at high loading, degrade in a controlled manner, release its cargo on demand, present acceptable toxicology and lend itself to surface engineering that dictates its fate in the body. MOFs meet these criteria in ways that conventional carriers such as liposomes, mesoporous silica and polymeric nanoparticles often cannot: their surface areas permit exceptionally high drug loading, pores of up to six nanometers accommodate molecules ranging from small-molecule drugs to peptides and large biomolecules, and their relatively weak coordination bonds allow the framework to decompose harmlessly and release its components. Loading can be achieved by diffusion into preformed crystals, by covalent attachment to the external surface, by in situ encapsulation during synthesis, or by using the drug itself as a ligand in framework construction.

Concrete examples illustrate the promise. A chiral zinc-based framework built from triazine-triisophthalate linkers absorbed the anticancer drug 5-fluorouracil through hydrogen bonding at a loading of 0.5 grams per gram and released it slowly over a week in buffered saline. In antibacterial applications, the iron framework MIL-53(Fe) physically loaded the glycopeptide antibiotic vancomycin to nearly 20 percent by weight and, under the acidic conditions that mimic a bacterial infection, released it in a controlled fashion that achieved 99.3 percent efficacy against Staphylococcus aureus while remaining biocompatible in vitro. ZIF-8 has been used to ferry the broad-spectrum cephalosporin ceftazidime, confirmed by element mapping in electron microscopy, and to co-deliver doxorubicin with the P-glycoprotein inhibitor verapamil in folate-targeted, PEG-coated particles that overcame multidrug resistance in tumor cells. A biomimetic nanoreactor combining ZIF-8 with the prodrug tirapazamine, the enzyme glucose oxidase and an erythrocyte membrane coating points toward cancer starvation therapy with improved delivery.

The range of biomedical uses continues to broaden. Copper nanowires sheathed in ZIF-8 slowed the release of antiviral copper ions, showed low cytotoxicity with 99 percent of kidney cells surviving after 48 hours, and were investigated against SARS-CoV-2 in infected cells; surface-functionalized MOFs bearing nystatin, folic acid or tenofovir can bind viral capsid proteins and immobilize viruses. Copper–BTC films grown directly on stent surfaces catalyze the production of nitric oxide from blood-borne s-nitroso-cysteine, improving blood compatibility, while MOF–polymer coatings have been shown to inhibit bacterial attachment to medical tubing under flow. Frameworks delivering ibuprofen to reduce brain inflammation or dopamine for neurological therapy, along with ATP-responsive zirconium systems, extend the concept into chronic disease management, although crossing the blood–brain barrier remains a formidable hurdle.

The review is refreshingly blunt about the obstacles that stand between laboratory success and clinical or industrial deployment. MOF toxicity, driven by metal ion release, particle size, shape and aggregation, can produce oxidative stress, inflammation and organ damage, and standardized toxicity testing protocols and long-term in vivo biocompatibility data are still lacking. Water stability in real treatment streams, biodegradability in physiological settings, regeneration and reuse of adsorbents, material costs and the reproducibility of green synthesis routes all demand further work. Compared with clinically established liposomes and hydrogels, MOFs carry biosafety uncertainty and more complex, expensive synthesis. Yet the trajectory is clear. With defect engineering, biocompatible metal choices, scalable continuous-flow production and rational linking of synthesis conditions to structure–performance relationships, the authors argue, these crystalline cages could become central platforms for sustainable water purification and personalized medicine alike, addressing some of the most pressing environmental and health challenges of the coming decades.

Subject of Research: Metal–organic frameworks for wastewater treatment and targeted drug delivery

Article Title: Emerging roles of metal organic frameworks in wastewater treatment and targeted drug delivery applications

Article References: Singh, P., Singh, G., Singh, C. K., Nitin, V., & Sodhi, K. K. (2026). Emerging roles of metal organic frameworks in wastewater treatment and targeted drug delivery applications. Discover Industrial Chemistry and Materials, 1(1), Article 12. https://doi.org/10.1007/s44508-026-00010-1

Image Credits: AI Generated

DOI: 10.1007/s44508-026-00010-1

Keywords: metal–organic frameworks, MOF synthesis, wastewater treatment, heavy metal adsorption, dye removal, drug delivery, targeted cancer therapy, biocompatibility, MOF membranes, stimuli-responsive release, antibacterial agents, water purification