Journal of Colloid and Interface Science

Nowadays N95 facial mask has gain huge attention due to COVID19 pandemic situation and it serves as the prime PPE. Though the microbes can be restricted to get inside the human body due to the presence of mask temporarily, but over the time, bacteria and other microbes may get entrapped into the threads of the mask itself and thus acting as a storage chamber of microbes. It is necessary to eliminate them from the mask surface. To do so different floral structured Nano-ZnO with variable oriented arrangement of petals were fabricated on the surface of the N95 mask and further characterized through instrumentations including XRD, FTIR,UV-Vis, Fluorescence-Spectroscopy, SEM, DLS. The average crystallite size calculated for synthesized four different ZnO nanoflower were 25.19 nm, 23.46 nm, 27.27 nm and 31.78 nm (for glycerol, PEG, EDTA, Chitosan assisted) respectively. The antimicrobial activity was investigated by standard microbial broth dilution assay and Kirby-Bauer test which assured the inhibition of the bacterial growth. The MIC-MBC value of ZnO nanoflowers for E.coli and B. subtilis were found to be effective at dilution of 250 {micro}g/ml and 100 {micro}g/ml. Additionally a modified Kirby-Bauer assay has been designed to investigate the killing efficiency of the bacteria (E.coli). O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=145 SRC="FIGDIR/small/719592v1_ufig1.gif" ALT="Figure 1"> View larger version (35K): org.highwire.dtl.DTLVardef@a76030org.highwire.dtl.DTLVardef@9bf1b3org.highwire.dtl.DTLVardef@19232forg.highwire.dtl.DTLVardef@54fe68_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOFig. - Graphical AbstractC_FLOATNO C_FIG

The emergence of antimicrobial resistance has been rapid, necessitating the development of alternative therapeutic approaches beyond traditional antibiotics. In this proof-of-concept study, we examined the antibacterial activity of citrate-stabilized, colloidally aggregated silver nanoparticles (AgNPs) against Escherichia coli by combining physicochemical characterization with experimental antibacterial testing The synthesis of silver nanoparticles was done through a modified thermal citrate reduction protocol, and UV-visible spectroscopy, dynamic light scattering (DLS), and zeta potential were used to characterize the nanoparticles. Spectroscopy analysis showed a clear surface plasmon resonance peak at 310-320 nm, indicating the formation of nanoparticles. DLS measurements showed that the dominant hydrodynamic diameter was around 250-270 nm, which is indicative of controlled colloidal aggregation, and near-neutral values of zeta potential indicated steric stabilization of the nanoparticle clusters. Agar tests demonstrated a clear zone of inhibition, and broth cultures showed a lower turbidity and slower bacterial growth with AgNPs. The above findings suggest that nanoparticles that are colloidally aggregated maintain a significant antimicrobial activity even though the surface area is lower than that of monodispersed systems. Mechanistically, the observed antibacterial effect can be explained by a multi-modal effect through direct membrane disruption, localized release of silver ions, and the induction of oxidative stress pathways in bacterial cells. The aggregated form could also help to increase the nanoparticle cell interactions through the provision of multivalent contact points of nanoparticles, and thus the antibacterial efficacy. Controlled colloidal aggregation of AgNPs is a promising approach to the development of effective and possibly more stable antimicrobial agents. These results indicate the possibilities of aggregated nanoparticle systems in fighting drug-resistant pathogens and a basis on future studies of its clinical use.

Biofilm extracellular matrix (ECM) varies with environmental conditions and substrate properties. Understanding the surface-biofilm relationship helps to perfect antibacterial strategies and to design new engineered living materials (ELMs). In this work, we studied how cationic and anionic polyelectrolyte coatings affect macroscopic features of Escherichia coli curli-producing biofilms, as well as the properties of their curli amyloid fibers. Cationic coatings limited biofilm spreading, increased their surface density and water absorption, which correlated with a higher yield of curli amyloid fibers with looser structure. In contrast, anionic surfaces allowed for standard biofilm spreading, with a lower fiber yield but a more compact and chemically stable fiber structure. Higher biofilm rigidity and adhesion were measured on both types of charged surfaces. Thus, we propose that the differences in biofilm macroscopic properties result from a trade-off between curli quantity and quality in the ECM, namely fiber density and molecular packing, as well as their interaction with water. Our findings provide insights on how the biophysical properties of the ECM can be controlled by tuning the substrate physico-chemical characteristics with charged coatings. This work opens up new avenues for developing antimicrobial strategies, as well as tailoring the properties of amyloid-based ELMs. TOC figure O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=82 SRC="FIGDIR/small/721109v1_ufig1.gif" ALT="Figure 1"> View larger version (22K): org.highwire.dtl.DTLVardef@191cd79org.highwire.dtl.DTLVardef@148f914org.highwire.dtl.DTLVardef@1d8c2f8org.highwire.dtl.DTLVardef@1e84eaf_HPS_FORMAT_FIGEXP M_FIG C_FIG

Lipid nanoparticles (LNPs) are the most successful drug delivery carrier to date, but optimizing lipid formulations to improve membrane fusion capabilities for effective drug release has been challenging due to lack of a quantitative measure for fusogenicity. Here we introduce a new framework based on small angle X-ray scattering to experimentally measure [Formula] for lipids used in LNP formulations such as glycerol monooleate (GMO) and ionizable lipids (SM-102 and ALC-0315). Q intrinsically captures spontaneous curvature (J0), which is traditionally used to assess fusogenicity. The change of cubic lattice parameters with temperature was measured for GMO-containing lipid mixtures, and the Q extracted quantitatively correlated with LNP fusogenicity power validated by fluorescence-based fusion assays and cryogenic electron microscopy. Fusogenicity of SM-102 and ALC-0315 was quantified by adding them to host membranes and assessing change in Q. This framework provides researchers with the ability to optimize the fusogenicity of LNP formulations for potent drug release and enhances understanding of parameters governing fusion in all biomembranes.

In vegetarian diets, phytate is known to disrupt the adsorption of minerals. Fortifying foods with phytase, a therapeutic enzyme known to mitigate phytate, might increase the uptake of important nutrients. Phytase is susceptible to environmental stress such as heat and acidic conditions encountered during food processing. Therefore, we developed and optimized a core-shell microparticle composed of a phytase-chitosan core and a shell consisting of cross-linked alginate-{kappa}-carrageenan. Ethanol was used to precipitate the microparticles, and the ethanol concentration was optimized along with the chitosan and phytase ratio and the alginate-carrageenan concentration, to form stable core-shell microparticles. The optimized core-shell microparticles have a loading capacity of 32.7% with a high encapsulation efficiency of 80.3% and uniform micro-size with a diameter of 3.2 {micro}m and a poly-dispersity index of 0.178. Loaded phytase retained 62.7% enzymatic activity after heat treatment and digestion conditions. These results indicate that core-shell microparticles are suitable for retaining enzyme activity within the food matrix under typical food processing conditions. HighlightsO_LIDevelopment of size-controlled core-shell microparticles to protect phytase C_LIO_LIPhytase-chitosan microparticles are surrounded by an alginate-{kappa}-carrageenan shell C_LIO_LIOptimization achieved 32.7% loading capacity with a uniform size of 3.2 {micro}m C_LIO_LICore-shell microparticles retained 62.7% enzyme activity after heat and digestion C_LIO_LIPhytase powder (2 mg) is required for a single maize meal C_LI

Silver (Ag+) ions are known to be toxic to bacteria, cells, organisms and living systems; yet its impacts on the locomotion of surface-crawling organisms remain poorly quantified. Here we investigated the short-term (0-6 hours) effects of Ag+ ions on the locomotion of Drosophila melanogaster larvae on flat agarose surfaces containing Ag+ ions at different concentrations (0, 1, 10, and 100 mM). By quantifying their locomotion, we found that Drosophila larvae showed shorter accumulated distances and reduced crawling speed. Additionally, we quantified the go/stop dynamics and peristalsis of the larvae and observed that Ag+ ions disrupted the normal, rhythmic, peristaltic contraction of the larvae and "trapped" them in the stop phase. Such toxic effects were dependent on Ag+ concentration and exposure duration.

Manufacturing and storage processes can expose microbes to oxidative stress, reducing viability and limiting their use in biotechnological applications. Here, we evaluate graphene quantum dots (GQDs) containing hydroxyl and carboxyl groups as protective additives that mitigate peroxide-induced oxidative stress in Escherichia coli. GQDs did not adversely affect bacterial growth under basal conditions and restored growth in the presence of hydrogen peroxide. Using the membrane-partitioning fluorescent probe C11-BODIPY, we found that GQDs reduced peroxide-induced oxidation in bacterial membranes. We further used redox-sensitive roGFP2 probes to monitor intracellular oxidative stress and found that GQDs suppressed intracellular hydrogen peroxide accumulation and attenuated disruption of glutathione redox homeostasis. Together, these results show that GQDs protect bacteria by limiting peroxide-driven oxidative damage at both membrane and intracellular levels. This work supports the potential use of GQDs as protective additives for microbial formulations that are susceptible to oxidative stress.

Microplastic (MP) pollution, which is present in the ecosystem in vast quantities, adversely affects human health and the environment, making it imperative to develop methods for its mitigation. The challenge of detecting or capturing MPs could potentially be addressed using plastic-binding peptides (PBPs). The ideal PBP for MP remediation would not only bind strongly to plastic, but also have other properties such as high solubility in water or great binding specificity to a certain plastic. However, the scarcity or absence of known PBPs for common plastics along with the lack of methods that can discover PBPs with all of the desired properties precludes the development of peptide-based MP remediation strategies. In this study, we discovered short linear PBPs with high predicted water solubility and binding specificity by employing an in-silico discovery pipeline that combines deep learning and biophysical modeling. First, a long short-term memory (LSTM) network was trained on biophysical modeling data to predict peptide affinity to plastic. High affinity peptides were generated by pairing the trained LSTM with a Monte Carlo tree search (MCTS) algorithm. Molecular dynamics (MD) simulations showed that the PBPs discovered for polyethylene, the most common plastic, had 15% lower binding free energy than PBPs obtained using biophysical modeling alone. PBPs with both high affinity and high predicted solubility in water were found by including the CamSol solubility score in the MCTS peptide scoring function, increasing the average solubility score from 0.2 to 0.9, while only minimally decreasing affinity for polyethylene. The framework also discovered peptides with high binding specificity between polystyrene and polyethylene, two major constituents of MP pollution, using a competitive MCTS approach that optimized the difference in affinity between the two plastics. MD simulations showed that competitive MCTS increased the binding specificity of PBPs for polystyrene and identified peptides with relatively great preference for either of the two plastics. The framework can readily be applied to design PBPs for other types of plastic. Overall, the high-affinity PBPs with desirable properties discovered by marrying artificial intelligence and biophysics can be valuable for remediating MP pollution and protecting the health of humans and the environment.

Many biochemical processes are dependent on the presence or absence of molecular oxygen (O2). Palladium-tetrapyrrol derivatives can be used to measure O2-concentrations and O2-turnover during biochemical reactions and microbial growth in standard microtiter plates (MTPs). Palladium(II)-5,10,15,20-(tetrapentafluorophenyl)-porphyrin (1; CAS 72076-09-6) and Palladium(II)-5,10,15,20-(tetraphenyl)tetrabenzoporphyrin (2; CAS 119654-64-7) are introduced with this study. Spectral analyses of both compounds revealed that fluorescence quenching by O2 is not evenly distributed throughout all wavelengths and can therefore be used ratiometrically. Experimentally determined fluorescence lifetimes are around 500 {micro}s and 300 {micro}s for 1 and 2, respectively. A simple protocol is disclosed, how to immobilize the indicators on the bottom of MTP wells to give clear transparent dye doped polymer layers. We propose a straightforward procedure of how fluorescence data can be processed and calibrated in terms of O2 concentrations. Diverse applications are demonstrated and discussed, which include oxygen consumption and production by microorganisms as well as by enzymatically catalysed biochemical reactions. Various aspects are critically considered, as there are e.g. the dependence of O2 solubility on temperature and salinity, the diffusion of O2 across diverse phase boundaries, the unwanted O2 ingress into the reaction volume, the oxygen binding capacity of the MTP plastic material and the pH-dependence of the sensor layer. The findings and methods presented here open up a broad variety of high throughput assays involving changes of dissolved O2 as measurands for biochemical and biological activity. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=98 SRC="FIGDIR/small/718663v1_ufig1.gif" ALT="Figure 1"> View larger version (30K): org.highwire.dtl.DTLVardef@4daa4dorg.highwire.dtl.DTLVardef@e7ab8aorg.highwire.dtl.DTLVardef@1af1149org.highwire.dtl.DTLVardef@97fea5_HPS_FORMAT_FIGEXP M_FIG C_FIG

Cotton-based antimicrobial textiles are attractive for applications requiring improved microbiological control, but their performance depends on effective surface functionalization and retention of the active materials after use and washing. In this work, cotton fabrics were functionalized with hydroxyl-rich graphene oxide (HGO), hydroxyl-rich reduced graphene oxide (H-rGO), and silver nanowires (AgNWs), either individually or in combined treatments, to investigate their deposition onto the textile surface, washing resistance, and preliminary antibacterial activity. The treated fabrics were prepared by immersion-based coating procedures, and the persistence of the deposited materials after repeated washing was evaluated by UV-Vis analysis of the residual wash solutions. Surface morphology before and after washing was examined by scanning electron microscopy. The results showed that graphene-based coatings, particularly HGO, exhibited stronger retention on cotton fibers, while AgNWs were partially retained after repeated washing cycles. SEM images confirmed the deposition of AgNWs on the cotton surface and showed that part of the coating remained associated with the fibers after washing. A preliminary antibacterial assay against Escherichia coli indicated that nanomaterial-treated fabrics inhibited bacterial growth relative to untreated controls, with the combined HGO/AgNWs treatment showing the most promising inhibitory trend under the tested conditions. These findings demonstrate the feasibility of producing cotton fabrics functionalized with hydroxyl-rich graphene derivatives and silver nanowires, supporting their potential as proof-of-concept antibacterial textiles with partial washing resistance.

Polydimethylsiloxane (PDMS) is an excellent material for the construction of biomimetic leaf replicas which reproduce leaf surfaces with high fidelity. This allows for the study of leaf surface-colonizing bacteria and the impact of the leaf topology on bacterial distributions and behavior. However, their application is limited to short-term experiments, as long term survival of microorganisms on their surface is not possible due to a lack of nutrient replenishment. On living leaves, nutrients diffuse across the cuticle via leaching, a process not yet replicated in biomimetic systems. Here, we explore whether water and fructose can be supplied to microbial colonizers on PDMS membranes by mimicking leaching. We created hybrid membranes by incorporating polymers (Carbopol, Pemulen, cellulose microfibers, cellulose nanocrystals, and polyvinylpyrrolidone) to enhance nutrient transport. We determined that bulk diffusion of water correlated negatively with membrane thickness and positively with polymer concentration. Further, fructose diffusion across hybrid membranes reached similar rates compared to isolated Populus x canescens leaf cuticles. Under high relative humidity, these membranes supported long-term bacterial survival. Our findings represent important steps towards the development of topomimetic leaf surfaces that sustain microbial life, enabling further investigation into the microbe-microbe interactions that take place on leaves.

Nanoplastics generated from plastic waste in our ecosystems are becoming increasingly prevalent as bulk plastics exposed to natural factors like water and sunlight fragment to the nanoscale over time. These incidental nanoplastics span a wide range of physicochemical properties, which makes studying nanoplastic interactions in biological systems difficult. Here, we characterized the behavior of incidental nanoplastics generated through mechanical abrasion within coacervate droplets to probe the surface properties of the nanoplastics. We used elastin-like polypeptides (ELPs) to create hydrophobic or charged coacervate microenvironments. Using optical microscopy and fluorescence quantification, we observed that nanoplastics made from polyethylene terephthalate (nPET), nylon 6 (nPA), and polystyrene (nPS) exhibited distinct partitioning behavior with more favorable interactions with hydrophobic droplets. This indicated that the hydrophobic polymer backbone was the predominate surface feature despite exposed functional groups of the incidental nanoplastics, in contrast to findings with model carboxylated latex nanospheres (nPS-COOH). Furthermore, the selective partitioning of incidental nanoplastics into the hydrophobic droplets was able to capture over 80% of nPET in solution, and after recovery of the protein droplet, was able to cumulatively capture over 75% of the nPET feedstock across multiple cycles. This work explores the nuanced surface characteristics of incidental nanoplastics, expands the application of coacervates as chemical probes, and demonstrates a biopolymer approach for effective nanoplastic removal.

Surface functionalization of inorganic quantum dot nanoparticles is of great interest in the application of these materials toward a wide range of biological applications where membrane interactions are critical. The use of amphiphilic lipids to functionalize the surfaces of quantum dots represents a promising alternative to produce water-soluble and membrane-active materials with facile tuning of the quantum dots surface properties. Here, we demonstrate an experimental approach that yields lipid-coated quantum dots with highly tunable surface charge by controlling the concentration of cationic lipids during preparation. Through fluorescence-activated cell sorting assays, we show that these cationic lipid-coated quantum dots can enhance membrane interactions and increase membrane labeling density in live HEK293 cells. We further employed coarse-grained molecular dynamics simulations to model the lipid self-assembly process using an implicit solvent force field and subsequently model the adsorption of lipid-coated quantum dots to model membranes. Our simulations show that we can control the effective surface charge of lipid-coated quantum dots and influence the strength of adsorption to oppositely charged lipid membranes, a process that is mediated by the release of counterions at the quantum dot-membrane interface. This work supports the future development of biocompatible and water-soluble inorganic nanoparticles with highly tunable surfaces, and provides mechanistic insight into how different lipids can influence nanoparticle-membrane interactions at a molecular scale.

Environmental pollution from leather industries have become a menace. The microbial remediation of industrial waste and its reuse for agriculture could be a beneficial outcome. In present study, the bioremediated Cr III in the effluents are further converted to value product - Chromium oxide NP. This ensures double edged benefit as effluent is bioremediated and Chromium oxide NP with several applications is derived. A noteworthy advancement of the research involved the green synthesis of chromium oxide nanoparticles using Tridax procumbens. The effluent bioremediated can be used for agricultural purposes. By effectively characterizing tannery effluent and isolating chromium-tolerant bacteria, the study not only demonstrate a practical bioremediation solution but also showcase the potential of green synthesis in producing chromium oxide nanoparticles. In conclusion, this research marks a significant advancement in environmental science, leveraging both biological and nanotechnological innovations to address pressing challenges in pollution control. The present study focuses on a novel process of obtaining chromium oxide nanoparticle from tannery effluent with several applications derived from bioremediated tannery effluent using a cost-effective and eco-friendly process. The nanoparticle has a stable particle size and exhibit antioxidant, anti-diabetic properties. This product offers a breakthrough solution for the leather industry and healthcare sector. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=132 SRC="FIGDIR/small/720289v1_ufig1.gif" ALT="Figure 1"> View larger version (52K): org.highwire.dtl.DTLVardef@192e96borg.highwire.dtl.DTLVardef@1aae28org.highwire.dtl.DTLVardef@19fd282org.highwire.dtl.DTLVardef@1b562f9_HPS_FORMAT_FIGEXP M_FIG C_FIG

The apparent pKa of ionizable lipids in lipid nanoparticles (LNPs) is a key determinant of RNA encapsulation during formulation and endosomal release after cellular uptake. However, it is difficult to predict the effective pKa of a given ionizable lipid solely from its solution pKa, because it is sensitive to the membranes composition, as well as solution conditions such as the salt concentration. We developed a simple continuum electrostatics model, based on Gouy-Chapman theory, to predict the shift in effective pKa for ionizable lipids in lipid bilayers as a function of salt concentration and membrane composition. We derive equations for the surface potential and fraction of lipids charged, which are solved self-consistently as a function of solution pH to extract the titration curve and effective pKa. The model shows that the shift in effective pKa is largest when the concentration of titratable lipid is high, and the effect is diminished by increasing salt concentration. We provide a python implementation of the model and an interactive notebook that will allow users to further easily explore the predicted pKa shifts as a function of formulation variables.

In mammalian cells, lipid monolayers support the integrity of lipid droplets (LDs), organelles that function as storage for neutral lipids. Liver-targeting illnesses such as liver cancer interrupt normal LD metabolism and prompt changes in the chemical content of these organelles, which can have effects on structural and organizational behavior of the lipids. In LDs, liver cancer induces concentric crystalline phases of cholesteryl esters (CEs) and triglycerides near the NL-monolayer interface, which become more pronounced as CE concentration increases. Yet, there is little known about how this phenomenon may link to persistence of undigested LDs in liver cancer patients. To shed light on this, all-atom molecular dynamics simulations were used to model LD micropipette aspiration experiments and gain insight into the effect of CE concentration on partitioning, structural, and mechanical properties of LDs. We successfully model micropipette aspiration by application of constant surface tension laterally, which stretches lipid bilayers and monolayers as the magnitude increased. The results show increased phospholipid packing due to insertion of CE fatty tails into the monolayer. Increasing CE concentration induces a non-linear change in surface packing defects on the LDs, notable rigidification, and stiffness. Taken together, these insights improve our understanding of the physical properties at the LD monolayer-core interface during liver cancer progression.

Ternary composite systems formed by lactoferrin (LF), sodium alginate (Alg), and Fe(II) were designed to investigate their potential as an iron delivery platform with enhanced protein stability. The ternary LF-Alg-Fe (LAF) composites demonstrated distinct structures depending on the LF to Alg ratio and the Fe(II) concentrations. At an LF to Alg ratio of 8:2 and final Fe concentrations between 20-30 mM, the system formed complexes stabilized by electrostatic interactions. Whereas Alg-rich formulations formed hydrogels stabilized by Alg-Fe(II) egg-box cross-linking. Rheological analysis and swelling behavior indicated a higher mechanical strength in LF-rich complexes and stronger network integrity in Alg-rich hydrogels, while intermediate LF/Alg ratios showed weaker structures overall. Fourier-transform infrared spectroscopy (FTIR) spectra showed no changes in functional groups or polymer structures after composite formation, confirming composite formation via non-covalent interactions. Thermal studies indicated that these ternary systems improved LF stability, evidenced by preserved secondary structure after heating using circular dichroism (CD), and an increased denaturation temperature compared with free LF in differential scanning calorimetry (DSC). In addition, in LF-rich formulations the Fe(II) release in aqueous solution was [~]50% while in Alg-rich formulations it was much lower (< 10%). LF-Alg-Fe composites exhibit distinct structures governed by protein-polysaccharide interactions and iron-mediated cross-linking, providing a potential strategy for protein stabilization and iron fortification in food systems.

The conformational dynamics of a model cationic protein in water and in the presence of anionic sodium dodecyl sulphate (SDS) and cationic cetyltrimethylamonium bromide (CTAB) surfactants at different concentrations were investigated using all-atom molecular dynamics simulations. Free-energy landscapes constructed along principal components reveal a compact, well-defined native basin at 25 {degrees}C in water, whereas elevated temperature (100 {degrees}C) induces a broadening of the conformational space and the emergence of multiple metastable states. The presence of surfactants further modulates this behavior in a concentration-dependent manner. Cluster population analysis shows that SDS promotes a highly heterogeneous ensemble characterized by reduced dominance of the native-like cluster, while CTAB partially protects the protein from thermal denaturation at higher concentrations. Radial distribution functions demonstrate strong accumulation of SDS headgroups around the protein and pronounced insertion of SDS alkyl tails into hydrophobic protein regions, indicating direct hydrophobic destabilization and micelle-assisted unfolding. In contrast, CTAB exhibits weaker headgroup association owing to electrostatic repulsion and reduced tail-hydrophobic contacts, suggesting a less disruptive interaction mechanism. At high concentration, CTAB aggregates provide a structured hydrophobic environment that stabilizes the folded state and suppresses denaturation. Together, these results provide a molecular-level picture of how surfactant chemistry and concentration govern the conformational stability of a cationic protein, highlighting the dominant role of hydrophobic interactions in surfactant-induced denaturation at high temperature. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=89 SRC="FIGDIR/small/717321v1_ufig1.gif" ALT="Figure 1"> View larger version (24K): org.highwire.dtl.DTLVardef@dcf96aorg.highwire.dtl.DTLVardef@17acdc7org.highwire.dtl.DTLVardef@15bdc2borg.highwire.dtl.DTLVardef@1d39f3c_HPS_FORMAT_FIGEXP M_FIG C_FIG

Micro- and nanoplastics (MNPs) are now recognized as ubiquitous dietary and environmental contaminants, yet practical strategies to reduce gastrointestinal exposure remain limited. This study evaluated whether Qi601, a heat-inactivated Limosilactobacillus fermentum biofilm-derived postbiotic, could bind plastic particles and reduce intestinal epithelial plastic burden. Prior probiotic studies have demonstrated live bacterial adsorption of MNPs and mitigation of MNP-associated toxicity in vivo; here, we evaluate whether a nonviable postbiotic preparation can produce analogous MNP-binding and epithelial-protective effects. Qi601 durably bound polystyrene nanoplastics under in vitro simulated digestion conditions. In Caco-2 intestinal epithelial monolayers, Qi601 reduced surface-associated and intracellular nanoplastic burden in both protection and rescue models, indicating decreased epithelial particle interaction both before and after established nanoplastic exposure. Multimodal imaging, including confocal microscopy, atomic force microscopy, and scanning electron microscopy, confirmed close physical association between Qi601 and nanoplastics. Finally, a first-in-human proof-of-concept chewing-gum study showed Qi601 binding in the human mouth to heterogeneous gum-derived microplastic fragments released during mastication. Together, these findings support the concept of postbiotic intervention for gastrointestinal epithelial protection against ingested MNPs.

Sea water desalination is a critical solution to global water scarcity, primarily relying on membrane-based technologies and reverse osmosis. Artificial water channels (AWCs) offer a promising solution for next-generation desalination membranes. Very promising channel building blocks for AWC is oligourea foldamers repeats. These biomimetic molecules, composed of unnatural amino acids, self-assemble into protein-like superhelical channels with water-filled pores, making them ideal candidates for selective water transport. In silico studies provide essential support to experimental efforts in designing novel oligoureas. However, such studies require a dedicated force field for now unavailable for these molecules. In this work, we developed a tailored force field for oligoureas by adapting parameters from two established protein force field families: CHARMM (CHARMM36m) and Amber (GAFF2), using their structural similarities to natural amino acids. Our objective was to identify a force field that reliably preserves the structural integrity of oligourea foldamers. We evaluated two distinct oligoureas using molecular dynamics (MD) simulations across increasing system sizes. By comparing simulation results with experimental data, we assessed key structural features, including folding patterns, stability, and pore shapes. Our findings demonstrate that the CHARMM-based force field consistently reproduces experimental observations for both foldamers, outperforming the Amber-based alternative. This newly developed CHARMM-based force field paves the way for further exploration of oligoureas, enabling deeper insights into their stability and efficiency in sea water desalination.