ACS Applied Bio Materials

Chronic wounds such as diabetic foot ulcers are typically more alkaline than healing wounds, making wound pH a valuable diagnostic and prognostic marker. However, point-of-care pH monitoring remains limited by the availability of point-of-care wound pH sensing systems that offer quantitative pH determination, low toxicity, and small portable detectors. Here, we report a colorimetric pH-sensing wound dressing that enables in situ pH detection using a conventional smartphone camera. The anionic pH-sensitive dye HPTS was loaded onto cationic microparticles and embedded within a calcium-crosslinked alginate hydrogel. Across the clinically relevant range of pH 6.0-9.0, increasing pH produced a progressively more intense yellow coloration, quantified through the blue channel of smartphone-acquired RGB images. The dressing displayed a strong, rapid, and reversible signal in vitro with low dye release. In a full-thickness excisional wound model in mice, wound pH changes were detected in vivo. The combination of a pH-sensitive colorimetric hydrogel with a conventional smartphone detector offers accessible wound pH monitoring at the point-of-care.

Conducting polymers are widely used in bioelectronic interfaces because of their mixed ionic-electronic conductivity, mechanical compliance, and compatibility with biological systems. However, their electrochemically driven structural dynamics have received little attention as a mechanism for mechanical cell stimulation. Here, we show that electrochemical actuation of poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) generates mechanical cues capable of activating endogenous mechanosensitive pathways in HEK293T cells. Transparent PEDOT:PSS films deposited on ITO exhibited a heterogeneous granular morphology and underwent potential-dependent microscopic deformation during electrochemical modulation. Direct optical tracking revealed displacement of the polymer boundary, with structural changes occurring preferentially in polymer-dense regions and propagating toward the film edge. When HEK293T cells were cultured directly on PEDOT:PSS, repeated electrochemical stimulation at -240 mV produced reproducible intracellular Ca2+ responses. Pharmacological inhibition with GsMTx4 attenuated the calcium response, whereas blockade of voltage-gated sodium channels with tetrodotoxin largely preserved it, supporting the involvement of mechanosensitive pathways in the cellular response. These findings identify PEDOT:PSS as an electromechanical biointerface in which electrochemical modulation can introduce a mechanical component alongside the established electrical function of the interface. This mechanical contribution should therefore be considered when interpreting cellular responses to conducting polymer- based electrical stimulation and provides a basis for engineering bioelectronic interfaces that deliberately couple electrical control with mechanotransduction.

Three-dimensional (3D) spheroid culture provides a physiologically relevant alternative to conventional two-dimensional culture, but reliable spheroid formation in microwells depends on limiting cell-substrate adhesion. Pluronic F127 is an amphiphilic triblock copolymer that forms a hydrated surface layer, reducing protein adsorption. Here, we evaluated whether this intrinsic anti-fouling property could restore an anti-adhesive surface in used microwell plates to promote spheroid formation. Using chondrogenic ATDC5 and pancreatic {beta}-cell INS-1 cells, we characterized spheroid assembly kinetics, F127 cytotoxicity, surface hydrophilicity, protein adsorption, and spheroid morphology including size and shape factor. Both cell types formed compact spheroids within 24 hours on commercial anti-adhesive microwells. F127 coating markedly reduced water contact angle and protein adsorption, confirming increased surface hydrophilicity and reduced protein fouling. In microwells stripped of their original surface coating, F127 coating amounts of approximately 0.011-0.045 mg/cm2 consistently promoted spheroid formation across both cell types. Soluble F127 concentrations were confirmed to be non-cytotoxic up to 0.625% (w/v), while even complete dissolution of the highest tested coating amount would correspond to only 0.025% (w/v) F127. This simple, reproducible, and low-cost surface-modification strategy may provide an accessible approach for re-functionalizing microwell platforms for 3D cell culture.

Hydrogels are widely used in sensing, delivery, and tissue engineering because their transport properties can be tuned through material design. However, while hydrogel permeability is often characterized using small molecules, many practical applications depend on the uptake and retention of much larger species, including protein conjugates and nanoparticles. Here, we systematically investigate how polyethylene glycol (PEG)-acrylate hydrogel microparticle formulation influences accumulation of signal-generating probes spanning a broad size range. We fabricated particles across a 36-condition design space varying nominal PEG-acrylate molecular weight, polymer weight percent, and UV crosslinking dose, and related formulation-dependent probe accumulation to particle swelling behavior. Increasing nominal PEG-acrylate molecular weight and decreasing polymer weight percent produced more highly swollen particles and strongly enhanced accumulation of fluorescent streptavidin conjugates, with the largest effects observed for bulky labels such as allophycocyanin and phycoerythrin. Gold nanoparticle accumulation was even more formulation-restricted, with detectable colorimetric signal observed primarily in the most permissive formulations. These findings establish design rules linking PEG hydrogel formulation to size-dependent accumulation and show that formulations suitable for small probes may be inadequate for larger reporters. More broadly, this framework may inform the design of hydrogels for particle-based assays as well as other applications where transport of macromolecules or nanoscale materials is important.

Two-photon polymerization (2PP) enables fabrication of hydrogel constructs with submicron, cell-scale resolution, but hydrogel-based bioinks are markedly more sensitive to process variability than conventional photoresists, and this sensitivity is further amplified when living cells are embedded in the resin. Post-processing evaluation, performed only after development, occurs too late to enable any corrective action. A full-factorial design of experiments across laser power and scan speed shows that fabrication outcome depends on both parameter choice and cell presence, with cells shifting and broadening the range of conditions yielding structurally sound constructs. However, substantial variability persists within each nominal condition and cannot be resolved by parameter refinement alone, indicating that outcome is governed by what occurs during each individual print rather than by the parameters set. To capture this, a layer-wise polymerization score is derived from pairwise comparisons of same-layer coaxial images, grounded in the psychophysics of relative judgment, and assembled into a Layer-wise Image Trajectory (LIT) for each print. Applied to both acellular and cell-laden formulations, LIT curves separate cleanly by post-processing outcome without any outcome label used in training, showing that fabrication quality can be predicted early in the build. Building on this signal, individual LIT curves are compared against statistical control limits derived from confirmed successful prints, enabling early detection of anomalous fabrication behavior at early-to-mid layers, well before development. To the best of the authors knowledge, this is the first application of in situ quality prediction and anomaly detection to cell-laden two-photon polymerization.

Rapid, selective detection of bacterial pathogens remains a central challenge. Here we report a label-free electrochemical biosensing approach that leverages protein-protein interaction (PPI)-derived peptides as recognition elements for rapid detection of Listeria monocytogenes (LM). The sensor design is inspired by the interaction between the LM virulence factor Internalin A (InlA) and the human host receptor E-cadherin (E-Cad1). Peptides derived from the InlA-binding domain of E-Cad1 were engineered as molecular recognition elements, with the E-Cad1(15-24) peptide displaying micromolar affinity and selective binding towards LM. Immobilization of these peptides on gold electrodes enabled bacterial detection by electrochemical impedance spectroscopy within 10 minutes, without labels or external signal amplification. A low peptide surface density was associated with enhanced binding-site accessibility and may facilitate multivalent interactions between the bacterial surface and the immobilized peptides. The platform produced a detectable response at experimentally tested concentrations as low as 1 CFU mL {superscript 1} and exhibited excellent selectivity under the conditions examined. This work introduces a chemically programmable, PPI-inspired biosensing paradigm that uses a reductionist approach and could potentially be extended to other pathogen targets.

Lung-targeted delivery of mRNA with lipid nanoparticles (LNPs) demonstrates high potential for therapeutic applications in pulmonary disorders. However, progress in pulmonary mRNA therapeutics is constrained by the challenges of engineering lipids that are both safe and highly effective at targeting the lungs. To meet these critical needs, we designed triazine-based (TZ) ionizable lipids with cyanuric chloride as the linker between the cationic head and the lipophilic tail, which allows for easy derivatization capable of systemic mRNA delivery. Three TZ-based lipids were synthesized using the same ionizable headgroups while differing in the carbon tail length and evaluated for their in vitro and in vivo protein expression. Notably, all three lipids result in pulmonary expression after intravenous administration, but the TZ lipid containing a C14 tail does so without any indication of thrombosis, both in vitro and in vivo as compared to other formulations. Our findings highlight the effect of minor chemical modifications driving altered in vivo activity, thus enabling new opportunities for safe pulmonary delivery of mRNA for lung-related diseases.

Understanding the physicochemical factors that govern siRNA nanocarrier assembly is essential for the rational design of effective delivery systems. By optimizing various lipid compositions, cholesterol content and PEG length we created a peptide-functionalized cationic liposomal platform made of DOPE/TAP lipids with cholesterol-anchored nona-arginine (R9-Chol) for siRNA complexation, intracellular transport and effective silencing of the target EGFR gene. Analysis of {zeta}-potential and dynamic light scattering allowed to rationally design formulation of stable, monodisperse nanoscale lipoplexes with a positive surface charge. With fluorescence polarization, circular dichroism and agarose gel electrophoresis we found an optimal siRNA:liposome complexation ratio of 1:77, which protected siRNA from ribonuclease-mediated degradation. Morphological imaging confirmed a shift from discrete vesicular structures to organized multilamellar lipoplexes, consistent with electrostatically driven self-assembly. In cellular studies, the optimized nanocarrier promoted efficient uptake of fluorescent siRNA in MDA-MB-231 cells and achieved functional delivery of anti-EGFR, leading to substantially reduced expression of the target gene at both transcript and protein levels. This work offers mechanistic understanding of peptide-assisted lipid:siRNA assembly and positions R9-functionalized DOPE/TAP liposomes as a promising platform for siRNA delivery.

Nile Red is widely used for the detection of microplastics because its fluorescence emission is sensitive to local polarity and can distinguish hydrophobic plastics from hydrophilic ones. The fluorescence of the molecular rotor, 9-(dicyanovinyl)-julolidine (DCVJ) is less sensitive to polarity but more to viscosity. DCVJ is less widely used for microplastic analysis, although it has been used to detect polystyrene nanobeads. Here, we compared these dyes with standard samples from the Hawaii Pacific University Polymer Kit 1.0 and confirmed that Nile Red, in general, was better for the detection and identification of microplastics. Fluorescence emission was analyzed using photography, as well as spectroscopy. The color and peak emission wavelength of some stained environmental microplastics were affected by additives. Raman spectroscopy was used to confirm the chemical identity of such samples. Although DCVJ emits green fluorescence on binding to some microplastics, a peak at 620 nm has been reported with polystyrene nanobeads, attributed to dimer/excimer formation. We confirmed this property and directly observed diffraction-limited spots using fluorescence microscopy, attributed to single or just a few nanobeads. Nile Red also stains polystyrene nanobeads and gave stronger signals than with DCVJ, but Nile Red was prone to false positives due to dye aggregation in aqueous solutions.

Introduction: Advanced biomaterials for regenerative medicine are increasingly expected to combine multifunctionality and compatibility with tissue-specific cellular processes. In this context, hydroxyapatite-based platforms modified through ionic substitution represent promising candidates, as they may integrate structural similarity to bone mineral with additional biological functionality and luminescent properties, enabling diagnostic applications and real-time monitoring. In this study, we evaluated whether silicate-phosphate substituted calcium hydroxyapatite Ca10(PO4)6-x(SiO4)x(OH)2 (where x = 1.5) co-doped with lithium(I), europium(III), and gadolinium(III) ions (Si-HAp-LEG) affects the osteogenic, chondrogenic, and adipogenic differentiation potential of human bone marrow stromal/stem cells (BMSCs). Methods: Human BMSCs were cultured under lineage-specific differentiation conditions in the presence of undoped silicate-substituted phosphate hydroxyapatite (abbr. as Si-HAp), which served as a control, and two distinct Si-HAp-LEG formulations differing in gadolinium(III) (Gd3+) as well as lithium (Li+) and europium(III) (Eu3+) ion concentrations: Si-HAp-LEG-221 (1 mol% Gd3+ ion) and Si-HAp-LEG-222 (2 mol% Gd3+ ion). Differentiation-associated phenotypic outcomes, including extracellular matrix formation and lipid accumulation, were evaluated using Safranin O, Alizarin Red, and Oil Red O staining. In parallel, biomaterial-induced molecular responses were characterized at the transcriptomic and protein levels using RT-qPCR for selected coding and non-coding RNAs and Western blot analysis for representative lineage-associated proteins. Results: Histochemical evaluation confirmed that, across all tested biomaterial groups, BMSCs retained the ability to form mineralized calcium deposits, proteoglycan-rich extracellular matrix, and intracellular lipid accumulation under osteogenic, chondrogenic, and adipogenic conditions, respectively. Quantitative staining analysis revealed no significant Si-HAp-LEG-dependent enhancement of terminal differentiation outcomes compared with undoped Si-HAp. In turn, the molecular response differed between biomaterials modifications. Si-HAp-LEG-222 induced the most prominent changes in transcriptional and post-transcriptional regulators, particularly within BMP/SMAD-associated pathways under osteogenic and chondrogenic conditions, underlying a potential link between gadolinium concentration and osteogenic lineage commitment. However, these transcriptomic responses were not mirrored by consistent changes at the protein level. The results suggest that silicate-phosphate substituted hydroxyapatite co-doped with Li+, Eu3+, and Gd3+ ions primarily affects the early regulatory pathways associated with BMSCs differentiation rather than enhancing their terminal maturation. Discussion: In conclusion, the collective data indicate that Li+, Eu3+, and Gd3+ ions LEG co-doping broadens the multifunctional potential of Si-HAp by introducing imaging-related properties while preserving its underlying pro-regenerative character. Li+, Eu3+, and Gd3+ ions co-doped LEG-substituted Si-HAp may therefore be considered a compatible biomaterial platform that maintains BMSC cellular plasticity and supports balanced, differentiation-dependent modulation of lineage-associated molecular responses.

1.Surface functionality and pH play a decisive role in governing the structural dynamics, hydration, and drug-binding behaviour of dendrimers. Here, all-atom molecular dynamics (MD) simulations were performed on five generations of PAMAM (G1-G5) and PETIM (G2-G6) dendrimers with O-core and N-core architectures, functionalized with amine, carboxylic acid, or sugar terminal groups under different protonation states. Protonation of the tertiary branch-point amines expands the dendrimer structure, increases internal porosity and hydration, and enhances structural fluctuations across both families. In contrast, non-protonated amine -NH2 (NP) and carboxylic acid -COOH (NP) terminated dendrimers, together with deprotonated carboxylate-COO- (DeP) systems, retain comparatively compact conformations. Sugar-functionalized dendrimers ({beta}-galactose-terminated PETIM and D-glucose-terminated PAMAM) are most hydrated and structurally rigid, whereas amine-terminated dendrimers exhibit the greatest conformational dynamics. PAMAM dendrimers with -NH2, -NH3+, and -COO- terminal groups are generally more hydrated than their PETIM counterparts. However, {beta}-galactose-terminated PETIM dendrimers are more hydrophilic than D-glucose-terminated PAMAM dendrimers. N-core PETIM dendrimers also adopt more compact and spherical conformations than equivalent O-core PETIM dendrimers. Drug-binding MD simulations show that curcumin binding is dominated by van der Waals (vdW) interactions, whereas doxorubicin complexation is primarily driven by electrostatic interactions. Among the investigated surface functionalities, -NH2 (NP), -NH3+ (P), -COOH (NP), and -COO- (DeP) terminations exhibit the most favourable drug-binding characteristics. Except for deprotonated carboxylate systems, curcumin binds more strongly than doxorubicin. Overall, these findings establish molecular-level relationships between surface functionality, protonation state, dendrimer architecture, and drug-binding behaviour, providing design principles for pH-responsive dendrimer nanocarriers with enhanced drug-loading and controlled-release performance. TOC O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=75 SRC="FIGDIR/small/742721v1_ufig1.gif" ALT="Figure 1"> View larger version (35K): org.highwire.dtl.DTLVardef@119bf29org.highwire.dtl.DTLVardef@1554d86org.highwire.dtl.DTLVardef@154a254org.highwire.dtl.DTLVardef@16d5c5b_HPS_FORMAT_FIGEXP M_FIG C_FIG

The red palm weevil, Rhynchophorus ferrugineus (Olivier) (Coleoptera: Curculionidae), is a globally invasive quarantine pest threatening palm cultivation across 49 countries and inflicting annual economic losses estimated at over USD 100 million. Weevil larvae burrow into palm trunks, causing progressive internal structural damage that rarely produces visible external symptoms until lethal injury has occurred, rendering early detection exceptionally challenging. In the absence of effective early-warning surveillance technologies, tens of thousands of infested palm trees have been removed across major palm-cultivation regions in the Middle East and Mediterranean basin. Rapid, sensitive detection of volatile organic compounds (VOCs) emitted by weevil colonies and infested palm trees therefore represents a critical unmet need for timely pest surveillance and intervention. Existing artificial gas sensors lack the chemical selectivity required to discriminate among structurally similar VOCs, and no validated field-deployable early-detection platform has been established to date. Here, we report a portable biohybrid sensor array that mimics insect olfaction by exploiting two classes of diagnostic chemical signatures: the male-released aggregation pheromone (4RS,5RS)-4-methylnonan-5-ol (ferrugineol) and ethyl ester volatile blends emitted by weevil-infested palm trees. The R. ferrugineus odorant receptor RferOR1 was stabilised in lipid nanodiscs and co-immobilised with two in vivo-synthesised odorant-binding proteins (RferOBP1768 and RferOBP23) on quartz crystal microbalance (QCM) transducers to construct the biohybrid sensing platform. The sensor array achieved selective detection of airborne ferrugineol at a limit of detection of approximately 60 parts per billion (ppb) under field conditions, distinguishing infested from healthy palms. OBP- and OR-functionalised sensors retained full functional activity for 12 and 7 months, respectively, under ambient storage, confirming operational robustness and shelf life suitable for long-term field deployment. This work translates the molecular architecture of the insect olfactory system into a practical, field-validated chemical sensor platform with direct applicability to early-stage R. ferrugineus infestation monitoring and sustainable integrated pest management. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=112 SRC="FIGDIR/small/744605v1_ufig1.gif" ALT="Figure 1"> View larger version (54K): org.highwire.dtl.DTLVardef@69f81forg.highwire.dtl.DTLVardef@120e05dorg.highwire.dtl.DTLVardef@16a0cb6org.highwire.dtl.DTLVardef@16889a8_HPS_FORMAT_FIGEXP M_FIG C_FIG

Precise control of growth factor delivery remains a challenge for directing stem cell differentiation in three-dimensional (3D) engineered tissues. In this study, engineered cell-like vesicles are used as programmable microenvironments to enable sustained and localized delivery of growth factors within visible-light-crosslinked GelMA hydrogels. Giant unilamellar vesicles (GUV) loaded with FGF-2 and TGF-{beta}3 were incorporated into bioinks with BM-MSC to drive keratocyte differentiation without repeated soluble growth factor supplementation. ELISA measurements confirmed the removal of non-encapsulated growth factors and the release of the vesicle cargo following induced vesicle rupture. Fluorescence monitoring showed a progressive reduction in detectable FGF-2- and TGF-{beta}3-loaded GUV during culture, while droplet-scale analysis demonstrated the co-deposition of cells and vesicles after printing. After 14 days of differentiation, differentiated cells expressed ALDH1A1, ALDH3A1, lumican, keratocan, and collagen I without induction of -SMA. Interestingly, keratocyte-associated differentiation was retained after drop-on-demand bioprinting, confirmed by qPCR analysis. These findings establish growth factor-loaded vesicles as bioprintable instructive niches capable of supporting localized keratocyte differentiation within 3D corneal constructs.

Nisin is a promising antimicrobial peptide widely used in food preservation due to its efficacy against Gram-positive spoilage and pathogenic bacteria. Although Nisin is increasingly applied in the food sector, the biopeptide suffers from instability within food matrixes and can rapidly lose its antimicrobial potential following interaction with food biomolecules. Thus, it is necessary to investigate approaches that can be employed to extend the stability and activity of Nisin. Hence, the aim of this study was to develop and characterise a chitosan-alginate polyelectrolyte microencapsulation system capable of enhancing Nisin stability while retaining antimicrobial activity. The microencapsulation of Nisin was achieved by pre-gelation of alginate using calcium chloride and subsequent direct electrostatic interaction between cationic Nisin and chitosan with pre-gelled anionic alginate at pH 5.0. Following microcapsule formation, physicochemical and structural characterisation was performed using Zeta potential determination and measurement of the polydispersity index (PDI) via dynamic light scattering. SEM micrographs were used to confirm morphology, while Fourier-transform infrared (FTIR) spectroscopy and high-performance liquid chromatography (HPLC) were utilised to assess chemical integrity and functional group preservation of encapsulated Nisin. Following this, stable microcapsules with diameters ranging from 150-200 nm and smooth surface morphology were obtained. Microcapsule formation was strongly influenced by formulation parameters, particularly pH, calcium ion concentration, and chitosan content, with deviations from optimal acidic conditions (< pH 5.0) resulting in aggregation, increased polydispersity, and reduced encapsulation efficiency. The microcapsules were monodispersed (PDI {approx} 0.30) and electrostatically stable, exhibiting a Zeta potential of approximately +36 mV. These microcapsules remained stable over a prolonged storage period of 21 days under refrigerated conditions while retaining antimicrobial activity against Bacillus cereus. Encapsulation efficiency reached approximately 65%, confirming effective retention of Nisin within the polymer matrix. Overall, the findings demonstrate that chitosan-alginate ionic gelation is a non-denaturing and effective encapsulation strategy for extending the functional stability of Nisin. These microcapsules show strong potential as natural antimicrobial delivery systems for food and beverage applications, particularly in acidic food matrices, with implications for improved food safety and shelf-life extension.

The effect of microcurrents on facultative microbial pathogens remains controversial. Solid cultures in Sabouraud Glucose Agar of the ubiquitous mold Aspergillus fumigatus were repeatedly treated with a commercially available device performing wireless conductive microelectrostimulation by 3.5 A microcurrent routed by spraying negatively charged air particles onto solid cultures in modified petri dishes. The treated cultures displayed increased growth compared to standard ones, but only as a function of mycelial density and total surface; the radial growth rate of the mycelium remained unaltered. The increased growth was positively related to the duration of the treatment. At the same time, secondary development (new mycelial loci within the dish) was greatly upheld due to treatment, as the spraying created microairstreams dislocating the fungal spores. These results imply perplexed kinetics of mycelial growth both with and without treatment, since the folding of the mycelial mat is observed regularly. Both the fungus response to the ES and the possible revision of growth kinetics create prospects for biotechnological and bioremediation applications but also imply biomedical considerations, regarding infection dynamics of mycelial fungi and their in situ resistance to immune responses and treatment.

A major barrier to scaling marine restoration and aquaculture is the lack of reliable tools to induce invertebrate larvae to settle and metamorphose when and where needed. Although microbial cues are known to induce metamorphosis in many invertebrates, existing methods rely on natural biofilms that are variable, difficult to standardize, and unsuitable for large-scale deployment. Here we introduce ReefTiles, a non-living bacterial coating that preserves inductive activity from metamorphosis-stimulating marine bacteria in a stable, reproducible format. Using both tubeworm and coral larvae, we show that dried and inactivated bacterial films retain full settlement-inducing capacity, matching or exceeding live biofilms while eliminating concerns associated with releasing viable microbes into the environment. Viability assays confirm inactivation, and the coating adheres reliably to common substrate materials. Because ReefTiles can be manufactured and stored at scale and tailored to different inductive strains, they provide a practical microbe-based biotechnology for enhancing larval settlement in reef restoration, sustainable aquaculture, and engineered marine infrastructure.

Antimicrobial resistance motivates the development of approaches capable of probing nanoparticle-bacterium interactions with nanoscale sensitivity. Here, synchrotron infrared nano-spectroscopy (SINS) is applied to investigate interactions between carbohydrate-coated silica nanoparticles and the Gram-negative model bacterium Escherichia coli at the single-cell level. Silica nanoparticles (SiO2) were coated with mannose, maltose, or trehalose to evaluate how surface carbohydrate chemistry influences their interactions with the bacterial envelope. Correlative electron microscopy revealed pronounced association of carbohydrate-SiO2 with the bacterial envelope, with features consistent with localization within the periplasmic region, whereas bare-SiO2 showed no detectable association. SINS measurements acquired directly on bacterial cells and at bacterium-nanoparticle interfaces revealed distinct, carbohydrate-dependent spectral signatures. Quantitative analysis of the amide I band used the I/I{beta} ; ratio, which describes the relative contributions of -helical and {beta}-sheet protein secondary-structure components, together with interface-dependent band-position analysis to characterize local spectral perturbations. Carbohydrate-SiO2 produced systematic changes in the I/I{beta} ; ratio, including at locations where nanoparticles were not directly observed, indicating that their effects extend beyond the sites of nanoparticle association. Comparison of measurements acquired on bacterial surfaces and at bacterium-nanoparticle interfaces further revealed that carbohydrate chemistry modulates both the magnitude and spatial extent of these spectral perturbations. Trehalose-SiO2 produced the largest interface-dependent amide I band shifts and a spectral component consistent with random-coil structures. Overall, these results demonstrate that carbohydrate surface chemistry modulates nanoscale protein conformational perturbations at the nano-bio interface and highlight SINS as a powerful approach for resolving chemically localized molecular responses at single-cell interfaces.

Graphene oxide (GO) has primarily been investigated as a carrier for intracellular delivery of therapeutic molecules. In previous work, we identified a cell type-dependent interaction pattern in which GO remained predominantly associated with the plasma membrane of cancer cells but was internalised by non-cancerous epithelial cells. Here, we explored whether plasma membrane-associated GO can be used as a platform to present bioactive ligands and influence cell-surface receptor signalling in cancer cells. To test this hypothesis, we targeted integrin receptors at the plasma membrane in glioblastoma cell models using an RGD-containing peptide non-covalently complexed with GO. We assessed GO-peptide interactions, cellular interactions/uptake, motility, and focal adhesion signalling readouts. Peptide association was quantified using a 2,4,6-trinitrobenzene sulfonic acid (TNBSA) assay, and GO was characterised by atomic force microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and colloidal measurements. Immediately after complexation, ~70% of RGD was associated with GO. Peptide association increased the nitrogen signal and shifted the principal GO XRD peak while retaining nanosheet morphology. Biological responses were examined in U87 and U251 glioblastoma cells with different integrin-positive fractions, and in non-cancerous BEAS-2B bronchial epithelial cells. Confocal microscopy showed that GO and GO:RGD remained predominantly localised on the plasma membrane in U87 and U251 cells, whereas greater intracellular localisation was observed in BEAS-2B cells. Importantly, GO:RGD significantly reduced key indicators of cell motility: cell velocity in U87 and U251 cells, with trajectory and mean-square-displacement analyses supporting restricted cellular movement. Free RGD had no significant effect, while GO alone produced a smaller reduction in motility only in U251 cells. No treatment significantly altered BEAS-2B motility. Flow cytometry also showed a reduced pFAK-associated signal in GO:RGD-treated U87 cells. These findings establish a proof of concept that the cell-line-dependent plasma membrane localisation of GO can be exploited as a membrane-associated nano-bio interface for cell-surface-active ligands, opening the way for the development of GO-based platforms that modulate receptor-mediated signalling and cell behaviour.

The outer blood-retinal barrier (OBRB) is the primary interface through which systemically circulating drugs reach the retina. A tool that measures delivery across this barrier would support the development of targeted therapies as alternatives to repeated intravitreal injection, and the screening of drugs that reach the retina as an off-target toxicity. Such a tool should deliver drugs fluidically through a vascular compartment, measure transport across the retinal pigment epithelium (RPE), and display disease phenotypes relevant to efficacy. Here we adapt the SiM platform, which places epithelium and endothelium in direct juxtaposition across a permeable, optically transparent silicon nitride nanomembrane. ARPE-19 and human umbilical vein endothelial cells (HUVECs) were used as development cell sources. ARPE-19 monocultures reached a transepithelial electrical resistance of 68 {+/-} 26 {Omega} cm2 by 28 days, and ARPE-19 + HUVEC co-cultures reached a small-molecule permeability of 6.34 {+/-} 1.3 x 10-4 cm min-1 within 14 days, a state reported elsewhere only after longer culture. The barriers developed an intervening basement membrane. Drugs perfused through the basal vascular channel crossed into an open apical well, where sampling and mass spectrometry showed transport correlating with lipophilicity, as reported in vivo. The device also displayed two clinically relevant phenotypes. Digoxin at a clinically toxic concentration reduced viability in the co-barrier by about half and doubled permeability. In a vascularized configuration, VEGF drove endothelial invasion of the RPE layer, as seen in neovascular AMD. The SiM-OBRB therefore satisfies basic design criteria for measurement of drug bioavailability, toxicity, and efficacy.

Musculoskeletal symptoms are frequently reported following silicone breast implantation. However, the biological mechanisms linking implant-derived silicone exposure to skeletal muscle alterations remain poorly understood, partly because the biological effects of silicone have long been debated in the context of its biocompatibility. Here, we chemically characterized the low-molecular-weight fraction of the breast implant silicone exposome, readily released from implant gel through gel bleed, and investigated its potential biological consequences using an integrated approach combining analytical chemistry, clinical transcriptomics and histology, and controlled in vitro muscle experiments. Transcriptomic analyses of periprosthetic tissues associated with silicone implant rupture revealed unexpected myogenic and neuromuscular signatures in tissue conventionally regarded as predominantly fibrous, together with alterations in lipid metabolism and transport. These findings were supported by histological evidence of close interactions between periprosthetic tissue and skeletal muscle. Chemical analysis of the implant-gel extract detected linear siloxane L2 and cyclic siloxanes D3-D8, with tentative assignment of D9. In vitro, C2C12 cells exposed to the implant-gel extract showed up to 30% reduced viability and decreased expression of key neuromyogenic genes. Together, these findings provide convergent chemical, clinical, and experimental evidence that low-molecular-weight constituents of the breast implant silicone exposome may constitute a biologically active exposure capable of affecting skeletal muscle. The associated alterations in lipid metabolism and transport further provide a mechanistic framework for investigating the cellular handling and potential tissue distribution of hydrophobic silicone-derived species. These findings position silicone gel bleed as a biologically relevant source of chemical exposure rather than solely a material-integrity phenomenon.