The technique, called continuous chaotic printing, relies on static mixers: passive elements with no moving parts that are inserted into extrusion printheads. As two or more inks flow through these elements under laminar conditions, the flow is repeatedly split, stretched, and reoriented. Each mixing element duplicates existing material interfaces, so the number of internal layers grows exponentially along the length of the mixer. Unlike approaches that demand microstructured nozzles, optical patterning systems, or external electric, magnetic, or acoustic fields, chaotic printing is inexpensive, scalable, and mathematically predictable—and it is gentle enough to handle fragile mammalian cells.

In the new study, the researchers pushed the platform beyond the traditional Kenics static mixer, testing three additional geometries borrowed from industrial chemical engineering: the Ross mixer, the Mini-SMX, and the full SMX. Each geometry stamps a distinctive microarchitectural fingerprint onto the printed filament. Kenics elements produce the familiar aligned, multilayered lamellae, reaching feature sizes of about 60 micrometers with four elements yielding 16 layers within roughly a millimeter. Ross-based constructs display asymmetric, wave- or flame-like architectures, while the Mini-SMX generates symmetric motifs reminiscent of flowers or radiant forms. The SMX mixer, evaluated with one and two elements, produces flame-like structures with pronounced segregation of the two ink phases toward opposite sides of the cross-section.

Critically, these patterns are not accidents. Computational fluid dynamics simulations of the flow at each mixer outlet closely mirrored the experimentally observed cross-sections of printed hydrogel fibers, confirming that chaotic advection under laminar flow is deterministic rather than stochastic. Complex spatial patterns emerge from repeated stretching and folding of fluid streams despite the absence of turbulence or any moving mechanical components. Under the printing conditions used—fluid viscosities close to that of water—the resulting microarchitectures are dictated primarily by mixer geometry and topology, not by random perturbations. That predictability means researchers can design an internal structure on a computer and expect to see it materialize in the printed filament.

The team also demonstrated the flexibility of the approach across three distinct deposition modes. In continuous wet-printing, filaments are extruded directly into a calcium chloride bath that crosslinks alginate. In dripping, discrete spherical constructs form by droplet detachment, yet the internal architecture survives the formation process intact. In direct ink writing, viscoelastic materials are patterned by pressure-driven extrusion into grid-like constructs, each filament retaining discernible internal microstructure. Reproducing such interleaved architectures by conventional extrusion printing would require ultra-fine nozzles and sequential layer-by-layer deposition of distinct domains, which is impractical for continuous filament fabrication. Chaotic printing achieves the same result in a single, high-throughput step.

Because the goal of chaotic printing differs fundamentally from classical mixing, the researchers reframed how mixer performance should be judged. In conventional applications, a static mixer is judged by how completely it homogenizes fluids, and mixers with higher Lyapunov exponents—measures of how rapidly neighboring fluid elements separate—such as the SMX are considered superior. In chaotic printing, the objective is not homogenization but the rapid generation of controlled interfacial area over short residence lengths. Quantifying the intermaterial perimeter separating red and green domains in printed cross-sections, the team found that interface growth is often approximately linear over the few mixing elements relevant to biofabrication, rather than exponential. The Kenics mixer was a notable exception, showing clear exponential growth consistent with its deterministic 2-to-the-n lamellar multiplication mechanism.

The fluid dynamics analysis revealed a fundamental trade-off. SMX-type mixers, with their intersecting baffle structures, generate the highest instantaneous rates of interface proliferation and the finest features, but they impose significantly larger pressure drops due to repeated obstruction and redirection of flow. The Ross mixer produces the sharpest velocity transitions and localized zones of accelerated flow near blade edges, which promote strong interface stretching but also create aggressive shear peaks. The Kenics geometry achieves effective flow reorientation with comparatively moderate pressure penalties and smoother shear distributions, making it particularly attractive for shear-sensitive living cells. The Mini-SMX emerged as a compelling middle ground, capable of high interface densities with a lower pressure cost than the full SMX design. The choice of mixer, the authors argue, should follow the architectural objective—feature size, structural regularity, energetic efficiency—rather than classical mixing metrics alone.

To prove the concept has biological teeth, the team turned to living systems. Caco-2 intestinal epithelial cells were printed within a blend of alginate and GelMA using a hollow tube, a three-element Kenics mixer, and a one-element SMX mixer. Cell viability remained high across all conditions at day one and day twenty after printing. More strikingly, constructs printed with the single-element SMX spontaneously developed organized multicellular clusters over three weeks, and immunofluorescence staining revealed expression of tissue-relevant markers including Villin and Vimentin, along with F-actin and nuclei. The chaotic microenvironment was permissive enough to support long-term culture, self-organization, and functional marker expression—from a minimal setup with no external fields or complex optics.

Bacteria provided an even more vivid demonstration of spatial control. Using a Mini-SMX printhead with two inlets and a single mixing element, the researchers printed Escherichia coli, a facultative anaerobe expressing green fluorescent protein, in the outer regions of fibers while confining Bifidobacterium bifidum, a strict anaerobe, to the core. The peripheral E. coli shielded the oxygen-sensitive B. bifidum from ambient oxygen, and after 48 hours the anaerobe reached approximately ten to the ninth colony-forming units per gram in structured constructs—significantly higher than in pre-mixed controls, where populations homogenized completely. This rational compartmentalization of a synthetic microbial consortium points toward gut-mimetic systems, controlled cross-feeding platforms, and engineered biofilms in which gradients of nutrients, metabolites, or mechanical properties can be designed into the material itself.

The third proof of concept moved from biology to chemistry. Phosphate-rich and calcium-rich gelatin inks were co-extruded through a printhead containing three Ross mixing elements, generating interdigitated domains with distinct ionic compositions embedded in a single continuous gelatin matrix. Calcium phosphate precipitated precisely at the internal interfaces between the domains, visualized by tetracycline-based fluorescence staining. Because both inks share the same polymeric matrix and are crosslinked throughout by transglutaminase, the construct remains mechanically integrated despite its chemically distinct microregions. This capacity to spatially program chemical transformations within soft materials opens routes to biomineralization, catalysis, and bioinspired composites with functional gradients or hybrid living-nonliving features.

Taken together, the work establishes static mixer geometry as a genuine design parameter—one that simultaneously controls microarchitecture, interface generation, shear exposure, and pressure loss. By expanding the chaotic printing toolbox beyond Kenics elements to Ross, Mini-SMX, and SMX geometries, and by validating the platform across wet-spinning, dripping, and direct writing, the researchers have broadened the design space available to bioprinting, soft matter, catalysis, and synthetic biology. The broader promise is seductive in its simplicity: complex, nature-like internal organization encoded passively within a printhead, in a single continuous fabrication step, using equipment that many laboratories already own. As the authors suggest, future directions may include interfacial reactivity for sensing, directed nutrient diffusion, and even the synthesis of inorganic phases within hydrogel scaffolds—turning chaos itself into a tool for structuring complexity.

Subject of Research: Chaotic bioprinting of microarchitected soft materials using different static mixer geometries

Article Title: From Flow to Function: Using Different Static Mixers to Fabricate Microarchitected Materials Via Chaotic Printing

Article References: Bolívar‐Monsalve, E. J., Ceballos‐González, C. F., Quevedo‐Moreno, D. A., Rendón‐Moreno, I. I., Cantoral‐Sánchez, A., Ambriz‐González, H., Alvarez, M. M., & Trujillo‐de Santiago, G. (2026). From Flow to Function: Using Different Static Mixers to Fabricate Microarchitected Materials Via Chaotic Printing. Advanced Science, 13(55), Article e76626. https://doi.org/10.1002/advs.76626

Image Credits: AI Generated

DOI: 10.1002/advs.76626

Keywords: chaotic printing, static mixers, bioprinting, microarchitecture, hydrogels, chaotic advection, computational fluid dynamics, synthetic microbial consortia, biomineralization, direct ink writing, soft materials, Caco-2 cells

The research, led by Unnikrishnan Kannan and corresponding author Saji George at McGill University, together with colleagues at Manipal Academy of Higher Education, the Canadian Light Source, and Christ University, set out to test a fundamental assumption in the field. Toxicity studies of microplastics and nanoplastics have largely depended on primary plastic particles with smooth surfaces, yet the particles to which humans are predominantly exposed in food and environmental matrices are secondary particles, generated by fragmentation of larger plastic items. If those real-world particles behave differently from laboratory standards, then much of the existing hazard literature may need re-examination.

To create realistic test materials, the team mechanically fragmented two of the world’s most common plastics: high-density polyethylene, widely used in containers and packaging, and polyethylene terephthalate, the polymer of beverage bottles. From this process they generated microplastic particles in the 100 to 350 micrometer range and nanoplastic particles below 1000 nanometers. Molecular fingerprinting confirmed a crucial point: the parent polymer identity was retained after fragmentation. In other words, the fragments were still recognizably HDPE or PET. What changed was everything on and just beneath the surface.

Using an array of physicochemical characterization techniques, the researchers found that smaller particles showed greater surface roughness, altered surface charge, reduced crystallinity, chemical heterogeneity, and enhanced surface oxidation. These are not cosmetic differences. Crystallinity reflects how orderly the polymer chains are packed; mechanical grinding shatters that order, leaving disordered, strained, and chemically unsatisfied structures at the newly created surfaces. Those defect-rich surfaces are precisely where reactive chemistry happens. The two polymers diverged in instructive ways: HDPE nanoplastics remained mainly hydrocarbon rich but structurally disordered, whereas PET nanoplastics became oxygen enriched, with increased contributions from carbon-oxygen single bonds and ester groups of the O-C=O type.

The functional consequences of these surface changes were assessed with two complementary approaches. Electron paramagnetic resonance, a technique capable of detecting unpaired electrons and therefore free radicals, revealed stronger radical-associated activity in nanoplastics than in microplastics. Chemical probe assays told the same story from another angle, showing enhanced abiotic generation of reactive oxygen species, the aggressive oxygen-containing molecules that can damage lipids, proteins, and DNA. Reactive oxygen species produced by the particles themselves, without any biological catalyst, represent a form of intrinsic chemical hazard that travels with the particle wherever it goes.

The team then asked whether this heightened oxidative activity translates into biological damage. In experiments with erythrocyte membranes, the red blood cell membranes served as a model target, nanoplastics induced greater membrane lysis than their microplastic counterparts. Membrane lysis, the rupture of the lipid bilayer that encloses cells, is a direct physical-and-chemical assault that depends heavily on the particle surface contacting the membrane. Rougher, more oxidized, more reactive surfaces appear to make that contact more destructive.

Cellular studies reinforced the pattern. When Caco-2 cells, a widely used human intestinal epithelial model, were exposed to the particles, the nanoplastics triggered greater intracellular oxidative stress. Because Caco-2 cells model the gut lining, the first biological barrier that ingested plastic particles encounter, this finding is particularly relevant to dietary exposure. The result links the physical process of fragmentation, through altered surface chemistry, to a plausible mechanism of harm inside human-relevant cells.

One of the most nuanced findings of the study concerns the protein corona. When the researchers allowed bovine serum albumin, a common blood protein, to coat the particles before exposure, the cellular oxidation was attenuated. This indicates that the accessible particle surface, not merely the particle’s size or polymer type, drives biological reactivity. A protein layer acts as a buffer, masking the reactive sites that would otherwise generate radicals and attack membranes. The implication is double-edged: in protein-rich environments such as blood or digestive fluids, some of the particles’ oxidative aggression may be dampened, but the underlying reactive capacity remains, ready to manifest wherever the corona is absent or stripped away.

Taken together, the results carry a clear message for hazard assessment. The smaller a plastic particle becomes through mechanical fragmentation, the more reactive its surface grows, and the greater its potential to generate reactive oxygen species, lyse membranes, and stress cells. This means that size is not merely a matter of where particles can travel in the body, the usual focus of nanoplastic concern, but also of what those particles do chemically once they arrive. Secondary nanoplastics formed in the environment may be intrinsically more hazardous than the smooth primary particles that dominate laboratory test kits, meaning current risk assessments built on model beads could underestimate real-world toxicity.

The study also highlights the value of methodological rigor. By combining molecular fingerprinting, electron paramagnetic resonance, chemical probe assays, membrane lysis tests, and cell-based oxidative stress measurements, the researchers built a chain of evidence connecting a physical process, mechanical size reduction, to altered surface chemistry and finally to biological effect. The work, conducted with facilities including the Canadian Light Source and McGill’s electron microscopy and imaging platforms and supported by NSERC and Canada Foundation for Innovation funding, offers a template for how future toxicity studies might evaluate realistic secondary particles rather than idealized ones. As plastic pollution continues to fragment across ecosystems, from ocean surfaces to kitchen countertops, understanding that every crack and grind marks a fresh, reactive surface may reshape how scientists, regulators, and the public judge the true hazard potential of the plastic particles we all encounter daily.

Subject of Research: Surface reactivity and toxicity of mechanically fragmented secondary microplastics and nanoplastics

Article Title: Surface reactivity of plastic particles increases with size reduction during mechanical fragmentation: Implications for hazard potential

Article References: Kannan, U., Sangeeth, K., Wang, J., Lukose, J., Vinod, T. P., & George, S. (2026). Surface reactivity of plastic particles increases with size reduction during mechanical fragmentation: Implications for hazard potential. Microplastics and Nanoplastics. https://doi.org/10.1186/s43591-026-00231-3

Image Credits: AI Generated

DOI: 10.1186/s43591-026-00231-3

Keywords: microplastics, nanoplastics, mechanical fragmentation, surface reactivity, reactive oxygen species, free radicals, electron paramagnetic resonance, membrane lysis, Caco-2 cells, HDPE, PET, oxidative stress

The experimental system was built on Caco-2 cells, a workhorse of gastrointestinal research. When grown under the right conditions, these human colorectal cancer cells differentiate into a monolayer that behaves remarkably like the lining of the small intestine, complete with absorptive properties, tight junctions between neighboring cells, and even the capacity to secrete enteroendocrine hormones. That makes them an ideal first-pass model for asking whether a botanical extract can influence the biology of the gut wall before any animal or human work is attempted. The team, led by Heggar Venkataramana Sudeep, first established a safety window using an MTT cytotoxicity assay, testing concentrations of the extract ranging from 25 to 500 micrograms per milliliter. Only concentrations that left the cells unharmed were carried forward, ensuring that any molecular changes observed were genuine regulatory effects rather than signs of cellular distress.

The headline finding concerns the GLP-1 system itself. After 24 hours of treatment, the highest non-toxic dose, 100 micrograms per milliliter, drove a 3.33-fold increase in the expression of the Proglucagon gene, the blueprint from which GLP-1 is manufactured, and a 3.32-fold rise in the gene encoding the GLP-1 receptor, the molecular dock that receives the hormone’s signal. Both changes were statistically robust, with the Proglucagon effect reaching a significance threshold of p less than 0.001. The paired upregulation is significant because it suggests the extract is not merely prompting cells to produce more hormone but also priming the signaling apparatus that responds to it, a combination the authors interpret as stimulation of endogenous GLP-1 signaling rather than a one-dimensional hormonal push.

Producing more GLP-1 is only half the battle, because the hormone is famously short-lived. An enzyme called dipeptidyl peptidase-4, or DPP-4, slices incretin hormones into inactive fragments within minutes of their release, which is precisely why a class of diabetes drugs called DPP-4 inhibitors exists to prolong GLP-1’s working life. The extract appeared to attack this problem from two directions. In the Caco-2 cells, Leanskolin significantly reduced both the activity of cellular DPP-4 and the expression of the gene that encodes it, compared with untreated controls. In a separate cell-free enzyme assay, the extract inhibited DPP-4 directly, with a half-maximal inhibitory concentration, or IC50, of 262.5 micrograms per milliliter. That potency is modest compared with synthetic pharmaceutical inhibitors, but the dual mechanism, suppressing the enzyme’s production while also dampening its activity, hints at a layered strategy for extending the bioavailability of the hormone the cells are producing in greater quantities.

Perhaps the most intriguing piece of the puzzle involves bitter taste receptors. It is now well established that the gut is not a passive tube but a sensory organ, studded with the same TAS2R bitter receptors found on the tongue. When these receptors detect bitter compounds, they can trigger cascades that influence appetite, hormone release, and gut motility. In the study, Leanskolin modulated the expression of three bitter receptor genes, TAS2R38, TAS2R43, and TAS2R14, in a concentration-dependent manner with statistical significance at p less than 0.05. The authors suggest this points to a role in nutrient sensing and enteroendocrine signaling, raising the possibility that forskolin or companion compounds in the extract act as bitter agonists that help coax the gut’s hormone-producing cells into action. If confirmed, this would place the extract in a growing family of bitter-tasting botanicals being investigated as natural modulators of gut hormone release.

The second major axis of the study concerned the physical integrity of the intestinal barrier. A healthy gut wall is a selectively permeable gatekeeper, held together by tight junction proteins that seal the gaps between epithelial cells. When that seal loosens, a condition sometimes called leaky gut, bacterial fragments and other unwanted molecules can slip into the bloodstream, fueling the low-grade inflammation that is increasingly implicated in obesity, insulin resistance, and metabolic syndrome. The researchers assessed barrier function using two complementary readouts. Transepithelial electrical resistance, or TEER, measures how well the cell monolayer resists the passage of ions, while FITC-flux assays track the movement of a fluorescent marker across the layer, a proxy for paracellular leakiness.

The results here were nuanced but encouraging. Treatment with the extract at concentrations from 25 to 100 micrograms per milliliter for 24 hours did not change TEER values, suggesting the overall ionic tightness of the monolayer was preserved rather than perturbed. However, FITC-flux dropped significantly at the 50 and 100 microgram doses, with p values below 0.01, indicating that the passage of larger molecules through the paracellular route was reduced. Consistent with that functional improvement, the extract enhanced the expression of tight junction proteins, the molecular rivets of the barrier, at p less than 0.05 compared with controls. In other words, the barrier was not merely being stressed into tightening; the cells appeared to be actively building more of the structural proteins that hold the wall together.

Taken together, the authors frame the extract as a multi-target agent for metabolic health, simultaneously activating GLP-1 pathway genes, curbing the enzyme that degrades GLP-1, engaging the sensory receptors that regulate enteroendocrine responses, and reinforcing the gut’s physical defenses. That combination matters because these processes are biologically intertwined. GLP-1 released from intestinal L-cells slows gastric emptying, promotes satiety, and enhances glucose-dependent insulin secretion, while a robust epithelial barrier limits the inflammatory signals that can drive insulin resistance. A single intervention that touches both sides of that equation is unusual, particularly one derived from a plant whose active constituent has been on the market for decades.

Caution is warranted before anyone reaches for a forskolin supplement expecting a natural Ozempic. This was a cell culture study, and the concentrations used, up to 100 micrograms per milliliter applied directly to cells in a dish, do not translate straightforwardly into human doses or blood levels. Caco-2 cells, though useful, are a cancer-derived model that only approximates real intestinal physiology, and gene expression changes do not guarantee meaningful hormone secretion in a living body. There is also a disclosure worth noting: all of the authors are employed by Vidya Herbs Pvt. Ltd., the company behind the Leanskolin ingredient, and the paper explicitly declares this potential conflict of interest. Independent replication in animal models and eventually controlled human trials will be essential to determine whether the effects survive the journey from dish to person.

Even with those caveats, the study opens a genuinely novel research direction. Forskolin has historically been studied for its ability to activate adenylate cyclase and raise intracellular cyclic AMP, a signaling molecule with wide-reaching effects, and it is tempting to speculate that this canonical mechanism could underlie some of the observed gene expression changes. But the breadth of the effects, spanning incretin genes, DPP-4, bitter receptors, and tight junction proteins, suggests the standardized extract may act through converging pathways rather than a single switch. As interest in gut-derived hormones reshapes metabolic medicine, the idea that a well-characterized botanical extract could engage the same biology, however gently, is likely to keep this line of investigation moving from the culture flask toward the clinic.

Subject of Research: Effects of a standardized Coleus forskohlii extract on GLP-1 signaling and intestinal barrier integrity in Caco-2 cells

Article Title: Targeting GLP-1 signaling and barrier integrity with Leanskolin™, a standardized Coleus forskohlii extract: a Caco-2 cell-based study for metabolic health support

Article References: Sudeep, H. V., Kumara, T. P. P., Lingaraju, H. B., & Shyamprasad, K. (2026). Targeting GLP-1 signaling and barrier integrity with Leanskolin™, a standardized Coleus forskohlii extract: a Caco-2 cell-based study for metabolic health support. BMC Complementary Medicine and Therapies. https://doi.org/10.1186/s12906-026-05590-1

Image Credits: AI Generated

DOI: 10.1186/s12906-026-05590-1

Keywords: GLP-1, forskolin, Coleus forskohlii, Caco-2 cells, DPP-4 inhibition, gut barrier, tight junctions, incretin hormones, metabolic health, bitter taste receptors, natural products, enteroendocrine signaling

The research began with an ambitious screening campaign. The team collected lactic acid bacteria from several varieties of kimchi, ultimately isolating forty distinct bacterial candidates. Because kimchi is a naturally fermented ecosystem, its microbial residents are diverse, and not every lactic acid bacterium is a promising probiotic candidate. To narrow the field, the researchers employed a three-tier identification strategy. First, they used random amplified polymorphic DNA profiling, a genetic fingerprinting technique that distinguishes closely related isolates by generating strain-specific banding patterns. They then constructed phylogenetic trees based on the 16S ribosomal RNA gene, the standard molecular barcode for bacterial identification, and confirmed species identity with species-specific polymerase chain reaction assays targeting diagnostic marker sequences.

This molecular gauntlet winnowed the forty isolates down to three confirmed L. sakei strains, designated RKA, RKC, and TAB. The choice of species was deliberate. L. sakei has an interesting dual reputation: it is well known in the food industry as a bioprotective organism that can suppress spoilage and pathogenic bacteria in chilled meats, yet it is also increasingly studied as a probiotic candidate, with prior clinical work exploring its effects on conditions ranging from dry eye disease to knee osteoarthritis. Strains isolated from fermented foods are considered attractive probiotic sources because they are already adapted to survive in harsh, acidic, and competitive environments, conditions that resemble the journey through the human gastrointestinal tract.

That survival ability was precisely what the Gachon team set out to quantify. A candidate probiotic must endure stomach acid and bile salts if it is to reach the intestine alive. When the researchers exposed their strains to acidic conditions, survival ranged from 33 to 85 percent depending on the strain, while tolerance to bile salts fell between 49 and 68 percent. These are meaningful figures, indicating that a substantial fraction of cells could withstand simulated digestive stresses. The team also measured traits linked to the ability of bacteria to colonize the gut lining. Cell surface hydrophobicity, a proxy for adhesion to intestinal epithelial cells, ranged from 11.5 to 25.6 percent with ethyl acetate and from 21.0 to 47.4 percent with hexane, while auto-aggregation, the tendency of bacterial cells to clump together and form protective biofilms, spanned 12.6 to 44.0 percent across the three strains.

Safety evaluation is arguably the most critical gatekeeper in probiotic development, and here the researchers ran a battery of tests. Hemolytic activity, the ability of bacteria to rupture red blood cells, a hallmark of many pathogens, was assessed, and none of the strains displayed the gamma-hemolytic patterns that would raise concern. Antibiotic susceptibility testing, conducted according to established clinical standards, showed that the strains were sensitive to most of the antibiotics examined, including carbenicillin, clindamycin, chloramphenicol, ampicillin, erythromycin, and tetracycline. The one caveat is that the strains showed resistance to cefoxitin and metronidazole. The authors note that such intrinsic resistance patterns are not unusual among lactic acid bacteria, but antibiotic resistance profiles remain a standard item on the safety checklist that regulators and the International Scientific Association for Probiotics and Prebiotics expect candidates to clear before any human application.

Beyond survival and safety, the study probed the functional chemistry of the bacteria, focusing on their cell-free supernatants, the liquid fractions left behind after cells are removed, which contain the metabolites the bacteria secrete. These supernatants demonstrated notable antioxidant capacity, scavenging 34.1 to 37.9 percent of DPPH radicals and 41.6 to 43.1 percent of ABTS radicals in standard colorimetric assays. The crude preparations, which included cellular material, showed weaker activity, ranging from 3.9 to 8.7 percent for DPPH and 11.0 to 17.3 percent for ABTS. Importantly, the researchers backed up these biochemical observations with genetics, detecting the presence of sod and katA genes, which encode superoxide dismutase and catalase, enzymes central to neutralizing reactive oxygen species. All three strains also tolerated hydrogen peroxide at various concentrations, reinforcing the picture of organisms equipped with robust oxidative stress defenses.

Perhaps the most striking result concerned antimicrobial activity. The cell-free supernatant of strain RKC outperformed its counterparts, inhibiting the growth of an impressive roster of problematic microbes: Escherichia coli, Bacillus subtilis, Pseudomonas aeruginosa, Staphylococcus aureus, and even the fungal pathogen Candida albicans. This broad-spectrum antagonism likely reflects the production of organic acids, hydrogen peroxide, and possibly bacteriocins, ribosomally synthesized antimicrobial peptides that many lactic acid bacteria deploy against competitors. The finding resonates with a growing body of literature showing that kimchi-derived lactic acid bacteria can disrupt biofilms formed by foodborne pathogens on seafood and food processing surfaces, suggesting potential applications not only as dietary supplements but also as natural biopreservatives in the food industry.

To assess whether these bacterial products could pose a risk to human cells, the team tested both crude preparations and cell-free supernatants against Caco-2 cells, a widely used laboratory model derived from human colon adenocarcinoma that mimics the intestinal barrier. The results were reassuring: no significant cytotoxicity was observed. This is an essential data point, because a probiotic candidate that harms intestinal cells in vitro would be a non-starter regardless of its other virtues. Combined with the hemolysis and antibiotic susceptibility results, the cytotoxicity data build a preliminary but coherent safety profile for the three strains, positioning them as credible candidates for the next stages of evaluation.

The authors are careful to frame their findings as a starting point rather than a finish line. They explicitly call for genome-based characterization of the selected strains, which would involve whole-genome sequencing to identify virulence factors, functional gene clusters, and transferable antibiotic resistance genes at a resolution that phenotypic tests cannot match. Such genomic work has become the expected standard in modern probiotic research, and comparative analyses of L. sakei genomes are already revealing how niche adaptation, whether in meat, fish, or fermented vegetables, shapes the functional repertoire of this species. Until that deeper characterization is complete, the study stands as a rigorous demonstration that the tangy, spicy world of kimchi continues to yield microbes of genuine biotechnological interest, and that strain RKC, with its standout antimicrobial activity, may be the one to watch as the field moves from screening bench to functional food development.

Subject of Research: Probiotic potential of Latilactobacillus sakei strains isolated from kimchi

Article Title: Screening, isolation, and identification of Latilactobacillus sakei strains from kimchi with potential probiotic properties

Article References: Sharma, P., Sharma, A., & Lee, H.-J. (2026). Screening, isolation, and identification of Latilactobacillus sakei strains from kimchi with potential probiotic properties. 3 Biotech, 16(9), Article 405. https://doi.org/10.1007/s13205-026-04978-7

Image Credits: AI Generated

DOI: 10.1007/s13205-026-04978-7

Keywords: kimchi, Latilactobacillus sakei, probiotics, lactic acid bacteria, antimicrobial activity, antioxidant, gut microbiota, cell-free supernatant, 16S rRNA, food fermentation, Caco-2 cells, biopreservation

The team, led by Yimei Zheng, Boyu Chen and colleagues at Guangdong Ocean University, built a self-microemulsifying drug delivery system, or SME, around luteolin. These systems are concentrated mixtures of oil, surfactant and co-surfactant that remain as clear liquids in a capsule but spontaneously bloom into nanoscale droplets, typically 20 to 100 nanometers across, the moment they meet gastrointestinal fluid. The sudden explosion of surface area dissolves lipophilic molecules that would otherwise sit undissolved in the gut lumen, protects them from oxidation and pH swings, and presents them to the intestinal epithelium in a form cells readily accept. What distinguishes this formulation from most previous nanocarriers is the deliberate choice of emulsifier: D-α-tocopheryl polyethylene glycol 1000 succinate, better known as TPGS, a Food and Drug Administration-approved amphiphilic polymer that happens to be a potent inhibitor of P-glycoprotein itself.

Formulation development began with pseudo-ternary phase diagrams, a classical pharmaceutical tool for mapping where oil, surfactant and water coexist as a stable microemulsion. The researchers combined TPGS as surfactant, polyethylene glycol 400 as co-surfactant and isopropyl myristate as the oil phase, titrating water into 25 different compositions and watching for turbidity and phase separation. The sweet spot emerged at a TPGS-to-PEG 400 mass ratio of 2:1, which produced the largest microemulsion region. Below that ratio, insufficient TPGS left interfacial tension too high; above it, the relative shortage of PEG 400 compromised co-solubilization. Oil content mattered just as much: higher proportions of isopropyl myristate destabilized the system by diluting the emulsifiers, echoing earlier reports that oil fractions above roughly 40 percent tend to yield unstable emulsions.

Three candidate formulations, designated TP12-I2, TP11-I2 and TP21-I3, were loaded with luteolin at 50 milligrams per gram of carrier and put through a demanding characterization gauntlet. Dynamic light scattering showed narrow, monomodal size distributions with mean droplet diameters below 50 nanometers. The formulations survived alternating 4 and 45 degree Celsius cycles, freeze-thaw swings between minus 20 and 25 degrees, and centrifugal stress in a LUMiSizer analyzer without significant changes in droplet size or visible phase separation. Transmission electron microscopy confirmed uniform, spherical particles with no aggregation. Fourier-transform infrared spectroscopy revealed subtle shifts in luteolin’s phenolic C–O stretch at 1265 wavenumbers and its carbonyl band moving from 1656 to 1653 wavenumbers, fingerprints of hydrogen bonding between the drug and its carrier, while ultraviolet-visible spectra retained luteolin’s characteristic 255 and 350 nanometer peaks, proving the molecule emerged chemically intact.

Release and antioxidant performance both improved markedly. In dialysis experiments, free luteolin plateaued after about 12 hours with only 9.23 percent cumulative release, whereas the encapsulated drug kept diffusing past the 24-hour mark, reaching 39.43 percent, a 4.3-fold enhancement driven by the enormous oil-water interfacial area of the nanodroplets. In DPPH and ABTS radical-scavenging assays, the SME formulations outperformed free luteolin at equivalent concentrations, an effect the authors attribute partly to improved solubility and partly to TPGS itself, which contributed measurable radical-scavenging activity of its own. Dye dispersion and conductivity experiments traced how the formulation behaves in the gut: below 40 percent water it forms water-in-oil structures, transitions through a bicontinuous phase between 40 and 70 percent, and completes inversion to a gut-friendly oil-in-water microemulsion above 70 percent hydration.

The cellular story is where the design philosophy pays off. Using Caco-2 monolayers, the gold-standard model of the intestinal barrier, the team showed that luteolin-SME accumulated inside cells at significantly higher levels than free luteolin within 15 minutes, with uptake rising linearly for an hour before slowing. Cooling cells to 4 degrees Celsius slashed uptake, proving the process is energy-dependent, and a panel of endocytosis inhibitors pinpointed the routes: chlorpromazine and nystatin, which block clathrin-mediated and caveolae-mediated pathways respectively, both suppressed uptake, while amiloride, a macropinocytosis blocker, had no significant effect. The nanodroplets, in short, enter intestinal cells through the same receptor-driven machinery cells use to internalize nutrients.

The P-glycoprotein evidence is the study’s most layered contribution. Verapamil and cyclosporine A, two canonical efflux inhibitors, each boosted luteolin uptake, confirming the flavonoid is a genuine P-gp substrate. TPGS alone also increased intracellular luteolin, and a rhodamine 123 assay showed that luteolin-SME reduced P-gp efflux activity in a concentration-dependent manner. Western blotting then revealed something subtler: the formulation downregulated total P-gp protein expression, with the effect scaling with TPGS content, suggesting both immediate functional blockade and a longer-term suppression of the pump itself. Molecular docking simulations tied the mechanism together at the atomic level, showing TPGS and luteolin bind the same substrate pocket of P-gp with binding energies of minus 8.0 and minus 7.2 kilocalories per mole, both hydrogen-bonding to the GLN-191 and THR-195 residues. TPGS, in other words, acts as a competitive antagonist that physically occupies the pump’s recognition site.

Permeability and pharmacokinetics translated the cellular mechanisms into whole-body numbers. Across validated Caco-2 monolayers with transepithelial electrical resistance near 900 ohms per square centimeter, the apparent permeability coefficients of the SME formulations ran 2.8 to 3.5 times higher than free luteolin, aided by a transient, fully reversible 25 to 35 percent loosening of tight junctions that recovered within 24 hours. In mice given 200 milligrams per kilogram orally, the area under the plasma concentration-time curve soared from 8.628 to 247.729 milligrams per liter times hours, a 29-fold increase, while peak plasma concentration jumped 16-fold from 1.705 to 27.546 milligrams per liter. Mean residence time lengthened from 3.889 to 6.57 hours, the half-life extended, and clearance dropped dramatically. Fluorescent biodistribution imaging with the dye DiR showed the formulation lingering in the intestine at 10 hours, long after the free-probe signal had vanished, and concentrating more strongly in liver and kidney.

Therapeutically, the payoff appeared in inflammation models. In lipopolysaccharide-stimulated RAW264.7 macrophages, luteolin-SME cut nitric oxide, TNF-α and IL-6 by roughly 77, 49 and 48 percent relative to the inflamed group, restored catalase and superoxide dismutase activities, suppressed the lipid peroxidation marker MDA, and reduced reactive oxygen species far more effectively than free luteolin, while nudging macrophage morphology from a pro-inflammatory M1 state toward an anti-inflammatory M2-like phenotype and protecting mitochondrial membrane potential. In an LPS-induced sepsis model in mice, the formulation lowered serum TNF-α, IL-6 and IL-1β by about 37, 26 and 39 percent, reduced the liver enzymes ALT and AST by roughly 65 and 64 percent, and preserved near-normal hepatic architecture under the microscope. Biosafety testing showed no cytotoxicity across intestinal, liver and macrophage cell lines and hemolysis rates below 5 percent. The authors present the platform as a general solution for poorly soluble, efflux-limited natural products, a class that includes many of the flavonoids now being studied for chronic inflammatory disease, and the 29-fold bioavailability leap suggests the strategy deserves close attention from anyone trying to turn promising plant chemistry into medicine that actually reaches the bloodstream.

Subject of Research: A TPGS-functionalized self-microemulsifying drug delivery system that enhances the oral bioavailability and anti-inflammatory efficacy of the flavonoid luteolin by inhibiting P-glycoprotein efflux.

Article Title: Boosting luteolin bioavailability via P-glycoprotein efflux inhibition: a self-microemulsifying drug delivery systems

Article References: Zheng, Y., Chen, B., Huang, X., Ai, C., Teng, H., & Chen, L. (2026). Boosting luteolin bioavailability via P-glycoprotein efflux inhibition: a self-microemulsifying drug delivery systems. Journal of Advanced Research, 88, 1095-1117. https://doi.org/10.1016/j.jare.2026.01.030

Image Credits: AI Generated

DOI: 10.1016/j.jare.2026.01.030

Keywords: luteolin, self-microemulsifying drug delivery system, TPGS, P-glycoprotein, oral bioavailability, flavonoids, Caco-2 cells, pharmacokinetics, anti-inflammatory, antioxidant, nanocarriers, sepsis

The research team, led by Mursalin Sajib and Lutz Grossmann at the University of Massachusetts Amherst together with USDA collaborators including Raymond Glahn and Karen Cichy, took five pulse flours through an identical low-moisture extrusion process: a Manteca-type yellow bean called USDA Yellowjacket, a commercial navy bean mix, California Blackeye 77 cowpea, and commercially purchased chickpea and red lentil flours. The goal was twofold. First, to test whether unrefined whole-pulse flours, with all their inherent chemical complexity, could be reliably extruded into expanded snacks. Second, to determine whether the type of pulse and the type of processing changed how much iron the human intestine could actually take up.

On the processing side, the answer was a qualified yes. Using a co-rotating twin-screw extruder with a barrel temperature profile reaching 160 degrees Celsius and a feed moisture of 20 percent, all five flours produced puffed extrudates, but with strikingly different properties. Specific mechanical energy and die pressure varied significantly across flours, reflecting differences in starch composition and lipid content. Chickpea flour, with roughly six percent fat acting as an internal lubricant, expanded the least and produced the hardest puffs, with an expansion ratio of only 2.44 and a hardness of nearly 25 newtons. Red lentil, with the lowest fiber content, expanded the most at 6.44 and yielded the softest product. Yellow and navy bean puffs landed in a favorable middle ground, with expansion ratios above 4.3, hardness values around 2.2 to 2.5 newtons, and relatively low water activity, performing comparably to red lentil, a pulse already established in commercial puffed snacks.

The nutritional story proved even more interesting. Total iron concentrations were highest in the yellow bean, navy bean and cowpea flours, and processing into porridge or puffs barely changed them. But iron content alone told almost nothing about bioavailability. When the researchers ran each product through an in vitro digestion followed by the Caco-2 cell bioassay, a validated model in which intestinal cells respond to iron uptake by producing ferritin, the differences were dramatic. Yellow bean porridges and puffs produced ferritin responses of roughly 30 nanograms per milligram of cell protein, far above every other pulse product and approaching, though not matching, the 44 to 49 nanograms per milligram seen with cooked ground beef and a plant-based burger reference. Navy bean products came second. Cowpea products, despite their high iron content, performed worst of all.

The explanation lay in the chemistry of inhibitors rather than the abundance of iron. Phytic acid, the classic antinutrient that chelates ferric iron in the gut, was reduced by both boiling and extrusion, with puffs showing greater reductions than porridges. All puffed products achieved phytate-to-iron molar ratios between 6 and 9, below the threshold of 10 associated with meaningful inhibition. Lectin activity, a safety concern in undercooked beans, was undetectable in all porridges and in most puffs, confirming that both processing routes rendered the products safe. Yet these improvements applied broadly and could not explain why yellow bean so clearly outperformed the rest.

The decisive factor turned out to be flavonoids, the polyphenols concentrated in bean seed coats. Flavonoids split into two camps with opposite effects on iron uptake. Enhancers such as kaempferol and its glycosides, along with epicatechin, keep iron soluble and available for transport. Inhibitors, particularly galloylated compounds like myricetin, delphinidin and gallocatechin derivatives, form stable, non-transportable iron complexes. The dose-response is brutally asymmetric: previous work has shown that adding just 10 percent myricetin to an epicatechin mixture cuts iron bioavailability by about 65 percent. Yellow bean flour was rich in kaempferol and its glucosides, with over 770 nanomoles per gram of kaempferol 3-glucoside, while containing essentially no inhibitory flavonoids. Cowpea, by contrast, carried a full payload of galloylated inhibitors, including myricetin 3-glucoside, delphinidin 3-glucoside and petunidin 3-glucoside, which persisted at elevated levels even after processing.

Statistical analysis confirmed the hierarchy of effects. Spearman correlation and principal component analysis converged on the same conclusion: cellular iron uptake correlated negatively with summed inhibitory flavonoids (rho of minus 0.75), zinc (minus 0.72) and phytic acid (minus 0.62), while total iron showed no significant correlation at all (rho of 0.12). The summed enhancer flavonoids were likewise uncorrelated with uptake, suggesting that their benefit is realized only when inhibitors are nearly absent, as they are in yellow bean. Extrusion itself provided a modest additional boost over porridge processing, most visibly for chickpea and red lentil, likely through disruption of cotyledon cell walls that otherwise shield iron from digestive enzymes.

The practical implications are considerable. A standard snack serving of 30 to 50 grams of yellow bean puffs could make a nutritionally relevant contribution to daily iron intake, which ranges from 8 milligrams for adult men to 27 milligrams during pregnancy, assuming the in vitro findings translate to human absorption. Beyond standalone snacks, the authors calculate that incorporating roughly 35 percent yellow bean flour into plant-based meat alternatives would deliver iron comparable to lean meat on a weight-for-weight basis, while also contributing about 17 percent protein and 20 percent dietary fiber. Because the flour is unrefined, no fractionation side streams are generated, aligning the approach with sustainability goals. The Manteca yellow bean market class has already been formulated into a pasta with higher iron bioavailability than enriched wheat or commercial chickpea and lentil pastas, though the authors caution that not all yellow bean market classes share these favorable traits.

Important caveats remain. The Caco-2 model measures cellular iron uptake rather than transepithelial transport or true fractional absorption in humans, and whole-meal context, iron status of the consumer, and unmeasured matrix components all influence real-world outcomes. The extrusion trials were limited to two independent replicates per flour, and the phenolic profiling was targeted rather than untargeted. The authors call for animal and human intervention studies, broader compositional screening, and testing of yellow bean ingredients within complete meals. Still, the central message stands: when it comes to plant-based iron, the company iron keeps inside the food matrix matters more than how much of it is there, and breeding and processing strategies that minimize inhibitory flavonoids while preserving enhancers offer a scalable, evidence-based route to better iron nutrition.

Subject of Research: Iron bioavailability in extruded whole-pulse snack foods

Article Title: Matrix-controlled iron bioavailability in unrefined whole-pulse low-moisture extrudates

Article References: Sajib, M., Wiesinger, J., Xie, H., Cichy, K., Hooper, S., Howe, K., Glahn, R., & Grossmann, L. (2026). Matrix-controlled iron bioavailability in unrefined whole-pulse low-moisture extrudates. Current Research in Food Science, Article 101589. https://doi.org/10.1016/j.crfs.2026.101589

Image Credits: AI Generated

DOI: 10.1016/j.crfs.2026.101589

Keywords: iron bioavailability, yellow bean, pulses, extrusion, phytic acid, flavonoids, Caco-2 cells, plant-based nutrition, iron deficiency, food matrix, snack foods, non-heme iron

The intestinal epithelial barrier is the body’s frontline customs office, a single layer of cells that decides what passes from the gut lumen into the bloodstream and what stays out. Its defining feature is the tight junction, a belt of protein complexes that seals the gaps between neighboring epithelial cells. These junctions perform what biologists call a gate-and-fence function: they permit the selective passage of water, ions, and nutrients through the spaces between cells while blocking bacteria and their toxins. When tight junctions fail, the result is the condition popularly known as leaky gut, in which unwanted molecules slip through and provoke inflammatory responses. Disrupted barrier function is implicated in inflammatory bowel disease, metabolic disorders, and a growing list of chronic conditions.

The key players at these junctions are the tight junction proteins, including occludin and members of the claudin family. Occludin, the first of these proteins to be identified, stabilizes the structural framework of the junction. Claudin-2, one of several tissue-specific isoforms, is associated with permeability properties of the intestinal epithelium, and its behavior is subtle: depending on context, it can either loosen or remodel the barrier. Another important player is lipocalin-2, an antibacterial, iron-sequestering protein of innate immunity that participates in the barrier’s defensive repertoire and is often induced by inflammatory stimuli. The inflammatory cytokine tumor necrosis factor alpha, meanwhile, can undermine the barrier by triggering the internalization of occludin, raising permeability.

Probiotic lactobacilli have repeatedly been shown to bolster this system. Certain strains of Lactiplantibacillus plantarum increase the production and correct localization of tight junction proteins by upregulating the genes that encode them, thereby reducing permeability and guarding against inflammation. Researchers have also explored postbiotics, the cell-free supernatants left behind after bacterial growth, which contain the bioactive metabolites of probiotic cultures without the living cells themselves. What has remained murky is how the food matrix itself contributes when probiotics are delivered as part of a fermented food, rather than as a purified supplement. The new study set out to probe exactly that boundary.

The team, led by Jihen Missaoui with colleagues at the University of Bari Aldo Moro in Italy and the University of Monastir in Tunisia, worked with two lactobacilli previously isolated from traditional zgougou: Lactiplantibacillus paraplantarum A1 and Lactiplantibacillus plantarum A2. They prepared these bacteria in three forms: living cell biomass from liquid culture, cell-free supernatant from the same cultures, and zgougou juice fermented with both strains together as a starter consortium. For comparison, they also prepared zgougou juice that had fermented spontaneously, relying on whatever microbes happened to be present. Each preparation was applied to monolayers of Caco-2 cells, a human colon cancer cell line that, when grown for 21 days on Transwell inserts, differentiates into a faithful in vitro model of the intestinal epithelium.

To gauge barrier integrity, the researchers measured transepithelial electrical resistance, or TEER, a standard technique in which a small current is passed across the cell layer; higher resistance means tighter junctions and a less permeable barrier. As a positive control, they challenged cells with lipopolysaccharide, a component of the outer membrane of E. coli that reliably disrupts tight junctions. The LPS treatment produced the expected time-dependent response, with resistance dropping significantly within 30 minutes before partially recovering. Against this baseline, the effects of the bacterial preparations emerged clearly, though not uniformly.

Exposure to the biomass of L. paraplantarum A1 raised TEER values significantly at early time points, an effect that depended on both the dose and the dilution used. The cell-free supernatant of the same strain increased resistance after six hours, and the biomass and supernatant of L. plantarum A2 produced significant boosts at 30 minutes. The most striking result, however, came from the fermented food itself. When the monolayers were treated with zgougou juice fermented by the two lactobacilli together, diluted tenfold, TEER values climbed to between roughly 690 and 963 ohms per square centimeter at every time point measured, dramatically higher than the untreated control. Spontaneously fermented juice produced a smaller but still significant effect at one time point. The combination of the two strains, embedded in the pine seed matrix, outperformed anything the bacteria achieved alone.

The molecular story behind these measurements proved equally intriguing. Using reverse transcription quantitative PCR, the team measured the expression of genes encoding occludin, claudin-2, lipocalin-2, and TNF alpha after 24 hours of exposure. Both bacterial biomasses and the driven-fermented juice significantly increased TNF alpha gene expression, yet an ELISA assay of the culture medium detected no corresponding increase in the protein itself. The authors attribute this discrepancy to post-transcriptional regulatory mechanisms that can block cytokine synthesis even when the gene is actively transcribed, a reminder that messenger RNA levels do not always translate into protein output.

More encouraging were the tight junction results. Biomass and cell-free supernatant of both lactobacilli significantly upregulated the genes for occludin and lipocalin-2, with the strongest effects seen at the tenfold dilution. The fermented zgougou juice, whether driven by the starter cultures or fermented spontaneously, significantly increased expression of both claudin-2 and occludin, with the spontaneous juice producing the strongest upregulation. The apparent tension between rising claudin-2 expression and rising TEER, which might seem contradictory given claudin-2’s association with permeability, is resolved by context: the functional impact of claudin-2 depends on the overall composition of the junction complex, and its overexpression here likely signals junction remodeling and epithelial homeostasis rather than a leaky barrier.

The authors hypothesize that the observed effects arise from a synergy between the bioactive compounds of Aleppo pine seeds, which are rich in linoleic and alpha-linolenic acids, flavonoids, and phenolics with antioxidant and anti-inflammatory activity, and the metabolic activity of the fermenting lactobacilli. Vegetable matrices may also protect probiotic bacteria during their passage through the stomach and small intestine, releasing them in the colon where they can interact directly with the host. The study is the first to show that fermented zgougou juice can upregulate genes encoding tight junction proteins in an intestinal cell model, and it underscores how traditional fermented foods, from kefir to kimchi, may modulate gut permeability through the combined action of microbes, their metabolites, and plant phytochemicals. The researchers caution that the effects are strain-dependent and shaped by the host and its resident microbiota, and they call for untargeted metabolomics to identify the specific compounds responsible, followed by animal studies to confirm whether the barrier-reinforcing effect survives the journey from the dish to the organism.

Subject of Research: Effects of Tunisian fermented zgougou and probiotic lactobacilli on intestinal epithelial barrier integrity in Caco-2 cell models

Article Title: Impact of Tunisian Fermented Zgougou and Related Lactobacilli on Caco‐2 Cell Barrier Integrity: Upregulation of Key Tight Junction Proteins

Article References: Missaoui, J., Liso, M., Lataoui, M., Limongelli, R., Minervini, F., Achour, L., & De Angelis, M. (2026). Impact of Tunisian Fermented Zgougou and Related Lactobacilli on Caco‐2 Cell Barrier Integrity: Upregulation of Key Tight Junction Proteins. Food Science & Nutrition, 14(10), Article e72387. https://doi.org/10.1002/fsn3.72387

Image Credits: AI Generated

DOI: 10.1002/fsn3.72387

Keywords: zgougou, Aleppo pine seeds, fermented foods, lactobacilli, probiotics, gut barrier, tight junction proteins, occludin, claudin-2, Caco-2 cells, TEER, postbiotics