ACS Applied Materials & Interfaces

Fetuin-A is a plasma protein of interest for bone-interfacing applications due to its role in mineralization processes through calcium/phosphate ion-binding capabilities. However, the role of fetuin-A in the initial stages of cellular interaction with biomaterials and the mechanisms involved are not fully clear. This work investigated the response of osteoblast-like Saos-2 cells to model gold substrates presenting pre-adsorbed fetuin-A as a surface modification, to determine the role of the protein in cell attachment and proliferation. Correlative quartz crystal microbalance with dissipation (QCM-D), surface plasmon resonance, and radiolabeling confirmed fetuin-A adsorbed on model surfaces in similar quantities compared to serum albumin but formed a less packed layer with increased water entrapment. Surfaces presenting pre-adsorbed fetuin-A enhanced cellular adhesion, similar to fibronectin, but attached cells displayed morphological characteristics more similar to those with pre-adsorbed albumin, with lower average surface area and maximum axis. Over 3 days, fetuin-A exhibited lower cellular proliferation compared to the fibronectin control, likely correlated to the decrease in cellular metabolism observed at the same time-point, and persisted over 7 days. These results provide insight into the role of adsorbed fetuin-A for bone-interfacing implant applications, suggesting the pre-adsorption of the protein alone aids cellular attachment, but is not sufficient to promote early stages of osseointegration.

Indwelling medical devices such as catheters and endotracheal tubes are major drivers of hospital-acquired morbidity and mortality due to bacterial colonization. The resulting healthcare-associated infections (HAIs) are further exacerbated by rising antimicrobial resistance, underscoring the urgent need for strategies that both prevent biofilm formation and reduce reliance on antibiotics. Polyvinyl chloride (PVC), a widely used material in medical tubing, is highly prone to bacterial attachment, making it a critical target for intervention. Here, we show that complete eradication of Staphylococcus aureus--both sessile on PVC and planktonic--can be achieved using a bovine serum albumin (BSA) amyloid-like coating in combination with vancomycin at a dose eight times lower than the MIC. While the amyloid film alone markedly reduces bacterial adhesion, the residual bacterial load still reaches infection-risk thresholds. This dual approach therefore not only prevents biofilm development but also significantly lowers antibiotic requirements, reducing the risk of resistance emergence and improving therapeutic safety. The coatings, deposited on PVC and on glass (as a model surface), were synthesized using dithiothreitol (DTT) as a reducing agent, as alternative to tris(2-carboxyethyl)phosphine (TCEP). Through optimization of the synthesis, the resulting films preserved their physicochemical and anti-biofouling properties while offering a simple, low-cost, and scalable approach. The coatings strongly adhere to both substrates, remain stable under aqueous and mechanical stress, and effectively suppress bacterial and mammalian cell adhesion without cytotoxicity. These properties are clinically relevant, reducing infection risk and mitigating tubing failure due to fibrous capsule formation, encasement, or crystallized biofilm-induced blockage. The demonstrated biocompatibility, robustness, and scalability of this coating platform underscore its translational potential as a clinically relevant strategy to mitigate HAIs, extend the functional lifetime of medical tubing, and alleviate the global burden of antimicrobial resistance.

Two-dimensional (2D) electronic materials hold immense promise for next-generation bio/neuro-electronic interfaces, but their biocompatibility has remained uncertain due to conflicting reports from studies focused on exfoliated flakes and suspensions. In this work, we present a comprehensive in vitro evaluation of electronic-grade large-area, chemical vapor deposition (CVD)-grown 2D materials - including platinum diselenide (PtSe2), platinum ditelluride (PtTe2), molybdenum disulfide (MoS2), and graphene - as substrates for mouse neural stem cell culture. Across all CVD-grown materials, the stem cells exhibited outstanding viability, with no significant differences in metabolic activity or live/apoptotic cell ratios compared to laminin-coated glass controls (p > 0.05). Importantly, these large-area 2D materials robustly supported neuronal differentiation, as evidenced by widespread {beta}III-tubulin expression. Strikingly, we found that flaky MoS2 promoted significantly greater neuronal maturation (>75% NeuN neurons) than any other substrate tested (25-50% NeuN; p < 0.05), revealing the critical influence of material format on bioactivity. While PtSe2 showed a tendency to promote glial lineage differentiation, our findings firmly establish large-area CVD-grown 2D materials as biocompatible, tunable platforms for neural interfacing, paving the way for their integration into advanced bio/neuro-electronic devices.

Undesired attachment of proteins, cells/bacteria, and organisms on material surfaces is problematic in industrial and health care settings. In this study, polymer coatings are synthesized from subunits of cyclodextrin, an additive/excipient found in food/pharmaceutical formulations. These unique polymers, which have been applied mainly towards sustained drug delivery applications, are evaluated in this study for their ability to mitigate non-specific protein adsorption, mammalian cell (NIH/3T3) adhesion, and bacterial cell (Staphylococcus aureus, Escherichia coli) attachment. Effects of cyclodextrin polymer composition, particularly incorporation of nonpolar crosslinks, on material properties and passive anti-biofouling performance are investigated. Results suggest that lightly-crosslinked cyclodextrin polymers possess excellent passive resistance to protein, cell, and bacterial attachment, likely due to the hydrophilic and electrically neutral surface properties of these coatings. At the same time, anti-biofouling performance decreased with increasing crosslink ratios, possibly a reflection of decreased polymer mobility, increased rigidity, and increased hydrophobic character. Cyclodextrin-based materials may be broadly useful as coatings in industrial or medical applications where biofouling-resistant and/or drug-delivering surfaces are required.

Biomaterials are widely employed across diverse biomedical applications and represent an attractive strategy to explore physiologically how extracellular matrix components influence the cellular response. In this study, we aimed to use previously developed biomimetic streptavidin platforms to investigate the role of glycosaminoglycans (GAGs) in bone morphogenetic protein 2 (BMP2) signaling. However, we observed that the interpretation of our findings was skewed due to the GAG-unrelated, non-specific adsorption of BMP2 on components of our biomaterials. Non-specific adsorption of proteins is a recurrent and challenging issue for biomaterial studies. Despite the initial incorporation of anti-fouling poly(ethylene glycol) (PEG) chains within our biomaterials, the residual non-specific BMP2 adsorption still triggered BMP2 signaling within the same range as our conditions of interest. To tackle this issue, we explored various options to prevent BMP2 non-specific adsorption. Specifically, we tested alternative constructions of our biomaterials on gold or glass substrate using distinct PEG-based linkers. We identified the aggregation of BMP2 at neutral pH as a potential cause of non-specific adsorption and thus determined specific buffer conditions to prevent it. We also investigated the induced BMP2 signaling over different culture periods. Nevertheless, none of these options resulted in a viable suitable solution to reduce the non-specific BMP2 signaling. Next, we studied the effect of various blocking strategies. We identified a blocking condition involving a combination of bovine serum albumin and trehalose that successfully reduced the unspecific attachment of BMP2 and the non-specific signaling. Furthermore, the effect of this blocking step was improved when using gold platforms instead of glass, particularly with Chinese hamster ovary (CHO) cells that seemed less responsive to non-specifically bound BMP2 than C2C12 cells.

Nanomaterials have been extensively investigated for their potential in delivering therapeutics to target tissues, but few have advanced to clinical application. The luminal surface of endothelial cells that line blood vessels are covered by a glycocalyx, a complex extracellular matrix rich in anionic glycans. However, the role of this glycocalyx in governing nanomaterial-cell interactions is often overlooked. In this study, we demonstrate that gold nanoparticles functionalized with branched polyethyleneimine (AuNP+) bind to primary human endothelial cells expressing either a developing or mature glycocalyx, with the interaction involving hyaluronan and heparan sulfate. Notably, the mature glycocalyx decreases the toxicity of AuNP+. In contrast, lipoic acid-functionalized gold nanoparticles (AuNP-) bind to endothelial cells with a developing glycocalyx, but not a mature glycocalyx. To further investigate this phenomenon, we studied charged polymers, including poly(arginine) (polyR) and poly(glutamic acid) (polyE). PolyE does not associate with endothelial cells regardless of glycocalyx maturity, but when glycans are enzymatically degraded, it can bind to the cells. Conversely, polyR associates with endothelial cells irrespective of glycocalyx maturity or glycan degradation. These findings highlight the intricate relationship between nanomaterial charge and presentation in interactions with endothelial cells, offering insights for modulating nanomaterial interactions with the blood vessel wall.

Lifitegrast is an FDA-approved drug that inhibits T-cell mediated inflammation associated with dry eye syndrome (DES). Lifitegrast is a potent inhibitor of the interaction between LFA-1 on T-cells and ICAM-1 on endothelial cells at the ocular surface. While effective in treating DES, 5% (81.2 mM) lifitegrast has low drug utilization and elicits off-target effects. Here we engineer contact lenses to release therapeutically-relevant doses of lifitegrast to every tear film for up to 10-hours. Lifitegrast is coupled to the polymer of the soft hydrogel lens via a photolabile (caged) crosslinker. Exposures of the lens to the 400-430 nm wavelengths of indoor daylight excite the caged crosslinker molecules and trigger a bond-cleavage reaction that releases authentic lifitegrast passively to the tear film. The photoproduct of the reaction remains chemically-linked to the polymer of the single-use lens. Our studies show that passive exposures of the lens to indoor light would generate an average of 990 nM lifitegrast to every tear film in a zero-order reaction for up to 10-hours. This concentration exceeds the Kd for the interaction between ICAM-1 and LFA-1 by [~]330-fold and would sustain inhibition of inflammatory responses at the ocular surface. The amount of lifitegrast released from the lens increases during exposures to outdoor sunlight. Over a 10-hour exposure to indoor light, a single lens would release 0.44% of the lifitegrast present in two drops of commercial 5% lifitegrast. Compared to tear-drop approaches, our engineered lenses would sustain the passive delivery of therapeutically-relevant doses of lifitegrast over a longer period, and exhibit improved drug utilization at a lower cost. Our technology could easily be integrated into daily-use contact lenses in order to prevent inflammation at the ocular surface, dry-eye and contact lens-mediated discomfort. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=198 HEIGHT=200 SRC="FIGDIR/small/439289v1_ufig1.gif" ALT="Figure 1"> View larger version (75K): org.highwire.dtl.DTLVardef@1049076org.highwire.dtl.DTLVardef@a83fceorg.highwire.dtl.DTLVardef@1f52c4borg.highwire.dtl.DTLVardef@12f0ead_HPS_FORMAT_FIGEXP M_FIG C_FIG

The transport of therapeutics and gene carriers to their site of action is often hindered by biological barriers, such as cell layers and basement membranes. Among these, the inner limiting membrane (ILM) represents a major barrier within the eye, separating the vitreous body from the retina. The ILM must be crossed, if for instance gene carriers are to reach retinal target cells following intravitreal administration. However, the ILM is a densely cross-linked basement membrane barrier, allowing only the smallest nanoparticles to pass. Here, we demonstrate that active micro-colloids decorated with enzymes can locally open the ILM and thereby facilitate the diffusion of passive carriers into retinal tissue. We utilize an ex vivo porcine eye model to determine the membrane permeability threshold using fluorescent nanoprobes. We further show that collagenase-decorated silica microparticles can facilitate the transport of nanoparticles, while exhibiting excellent biocompatibility with no adverse morphological or functional retinal effects over a six-week in vivo evaluation in a porcine model. Overall, our findings introduce a biocompatible and minimally invasive strategy to facilitate the targeted nanoparticle transport across biological barriers, which we demonstrate for retinal delivery enabled by active colloids.

Effective tissue regeneration and immune responses are essential for the success of biomaterial implantation. Although the interaction between synthetic materials and biological systems is well-recognized, the role of surface topographical cues in regulating the local osteoimmune microenvironment--specifically, their impact on host tissue and immune cells and their dynamic interactions--remains underexplored. This study addresses this gap by investigating the impact of surface topography on osteogenesis and immunomodulation. We fabricated MXene/Hydroxyapatite (HAP)-coated surfaces with controlled 2.5D nano-, submicro-, and micro-scale topographical patterns using our custom bottom-up pattering method. These engineered surfaces were employed to assess the behavior of osteoblast precursor cells and macrophage polarization. Our results demonstrate that MXene/HAP-coated surfaces with microscale crumpled topography significantly influence osteogenic activity and macrophage polarization: These surfaces notably enhanced osteoblast precursor cell spreading, proliferation, differentiation, and facilitated a shift in macrophages towards an anti-inflammatory, pro-healing M2 phenotype. The observed cell responses indicate that the physical cues from the crumpled topographies, combined with the chemical cues from the MXene/HAP coatings, synergistically create a favorable osteoimmune microenvironment. This study presents the first evidence of employing MXene/HAP-multilayer coated surfaces with finely crumpled topography to concurrently facilitate osteogenesis and immunomodulation for improved implant-to-tissue integration. The tunable topographic patterns of these coatings, coupled with a facile and scalable fabrication process, make them widely applicable for various biomedical purposes. Our results highlight the potential of these novel coatings to improve the in vivo performance and fate of implants by modulating the host response at the material interface.

Antibacterial additive use has surged due to rising incidences of food contamination, despite concerns over antibiotic resistance. Bacteriophage (bacterial viruses) represent a unique and promising opportunity as antibacterial agents, offering targeted bacterial lysis while being food safe. However, their commercial success has been limited by the significant diffusion barriers they face within food, preventing effective delivery at contamination sites. Here, we introduce bacteriophage-loaded microneedle patches that enable targeted phage delivery directly within food, eliminating internal pathogens in a minimally disruptive manner. The application of microneedles within food is first explored. The platform is then substantiated by comparing performance in raw beef and cooked chicken, where we achieved up to 3-logs reduction in Escherichia coli, thus providing complete decontamination according to regulatory limits. In contrast, conventional surface application of the same phage failed to provide significant decontamination. To ensure broad applicability, phage cocktails were also loaded into microneedles to demonstrate polymicrobial decontamination against other common food contaminants including Salmonella. This platform can also be adapted to extend food shelf-life by targeting spoilage-inducing bacteria.

1Self-assembled monolayers (SAMs) have been widely utilized as a way of tailoring surface chemistry through the adsorption of organic molecules to different materials. SAMs are easy to prepare and offer a wide variety of organic molecules that afford additional or improved properties to the coated material. Spatial control of SAM placement has been achieved over many length-scales, even at the nanoscale. However, nanopatterned SAMs are usually prepared through serial processes utilizing atomic scanning probes or soft-lithography utilizing elastomeric masters. These techniques are expensive or not repeatable. Here we present the use of nanospheres for the creation of nanopatterned Au:Cu films which spatially control the grafting of a thermoresponsive SAM made from poly(N-isopropyl acrylamide) (PNIPAM). Chemical characterization validates the presence of PNIPAM and environmental atomic force microscopy showed its response to temperature which was evidenced by a change in stiffness. Our approach represents an affordable large area methodology for repeatable spatial control of SAMs at the nanoscale.

Infections are a significant risk to patients who receive medical implants, and can often lead to implant failure, tissue necrosis, and even amputation. So far, although various surface modification approaches have been proposed for prevention and treatment of microbial biofilms on indwelling medical devices, most are too expensive/complicated to fabricate, unscalable, or limited in durability for clinical use. Here we present a new bottom-up design for fabricating scalable and durable nano-pattered coatings with dynamic topography for long-term antibacterial effects. We show that MXene layer-by-layer (LbL) self-assembled coatings -- with finely tunable crumple structures with nanometer resolution and excellent mechanical durability -- can be successfully fabricated on stretchable poly(dimethylsiloxane) (PDMS). The crumpled MXene coating with sharp-edged peaks shows potent antibacterial effects against Staphylococcus aureus and Escherichia coli. In addition, we find that on-demand dynamic deformation of the crumpled coating can remove [&ge;]99% of adhered bacterial cells for both species, resulting in a clean surface with restored functionality. This approach offers improved practicality, scalability, and antibacterial durability over previous methods, and its flexibility may lend itself to many types of biomaterials and implantable devices.

The development of an effective for subcutaneous or intradermal injection drug delivery requires systems with improved bioavailability and biocompatibility. Systematic physicochemical and biological interrogation of carnauba-wax/red-palm-oil lipid nanoparticles (LNPs) stabilised with d--tocopheryl-PEG-1000-succinate and polysorbate-40 shows that purposeful matrix engineering yields a robust sub-50 nm carrier for under-skin delivery. Cryo-TEM and SAXS uncover a disc-toroid hybrid morphology dominated by 30-40 nm particles with toroidal/disc shape - an advantageous biconcave geometry to enhance surface-to-volume ratio and is expected to accelerate enzymatic erosion after injection. Orthogonal analytics (AF4-MD, DLS, MALS, WAXS) confirmed that loading with quinine or dihydroartemisinin leaves size and crystallinity unchanged while delivering encapsulation efficiencies of approximately 90 % and long-term particle stability up to 18 months at 4 {degrees}C. Red-palm oil and the dual-surfactant corona act synergistically to suppress bimodality and narrow size distribution compared with single-component controls. Short-term viability assays in keratinocytes, fibroblasts and macrophages showed no cytotoxicity even at [&ge;]1 % (w/v) lipid, underscoring excellent biocompatibility. Fluorescein-labelled LNPs injected into ex vivo human skin traversed the dermis and hypodermis, while only nanomolar lipid concentrations appeared in the receiver medium, indicating a sustained local depot. Collectively, these insights link composition, structure and performance, positioning wax-based disc-toroid LNPs as a flexible platform for high-load delivery of small-molecule or biopharmaceutical therapeutics via minimally invasive under-skin administration.

Nanoscale-based tools for immunomodulation are expected to offer a rich battery of options for more targeted and safer approaches to achieve clinically effective manipulation of the local and systemic immune environment. In this study, we aimed to design nanoscale constructs based on graphene oxide (GO) nanosheets as platform carriers for the TLR7/8 agonist Resiquimod (R848). The non-covalent complexation of R848 molecules on the GO surface resulted in stable complexes by preserving their biological activity. The physicochemical properties, molecular quantification, as well as the overall performance of the complex were systematically investigated. We hypothesized the formation of GO:drug nano-constructs with strong colloidal stability over time, due to the strong {pi}-{pi} interactions between the R848 molecules and the GO surface, and identified that R848 loading efficiency consistently ranged around 75% (of starting molecules), quantified by HPLC and UV-Vis. The 2D morphology of the thin nanosheets was retained after complexation, determined by various (AFM and SEM) microscopic techniques. Based on the surface physicochemical characterization of the complexes by Raman, FTIR, XPS, and XRD, the formation of non-covalent interactions among the GO surface and the R848 molecules was confirmed. Most importantly, GO:R848 complexes did not compromise the biological activity of R848, and effectively activated macrophages in vitro. Collectively, this study demonstrates that thin GO sheets can act as platforms for the non-covalent association with small TLR7/8 agonist molecules, forming stable and highly reproducible complexes, that could be exploited as effective immunomodulatory agents.

Under acidic conditions, polycationic polymer coatings function as protective immobilization supports through protonation-mediated local pH buffering. However, it remains unclear how polymer support design parameters, such as film thickness and charge density, govern that vital protonation process. Leveraging the precise control of film thickness and copolymer composition enabled by initiated chemical vapor deposition (iCVD), we systematically investigated how these parameters govern the protonation behavior of poly[glycidyl methacrylate-co-2-(dimethylamino)ethyl methacrylate] (pGD) thin films and, in turn, the activity of immobilized {beta}-galactosidase (LacZ). Infrared spectroscopy suggests that proton penetration was capped at a depth of [~]250 nm in pGD with 65% DMAEMA, limiting the polycationic thickness in pGD films thicker than this value. Consistent with this limit, immobilized LacZ activity under acidic stress (pH 4) increased with protonated thickness up to [~]250 nm and then plateaued. Raising the polycationic monomer content from 25 to 65 mol% increased LacZ activity at pH 4 by up to 83%, consistent with a higher positive charge density providing stronger local pH buffering. To test whether this behavior depends on immobilization sites, we evaluated two approaches: random immobilization (via amine-epoxy ring-opening reactions) and site-directed immobilization (via SpyCatcher/SpyTag binding). Directed immobilization preserved higher LacZ activity than random immobilization, but the protonation-dependent protection trend remained consistent for both strategies. These findings establish protonation depth and charge density as tunable design parameters for polycationic immobilization supports that stabilize enzymes under acidic conditions.

Post-operative infection is a major complication in patients recovering from orthopaedic surgery. As such, there is a clinical need to develop biomaterials for use in regenerative surgery that can promote mesenchymal stem cell (MSC) osteospecific differentiation and that can prevent infection caused by biofilm-forming pathogens. Nanotopographical approaches to pathogen control are being identified, including in orthopaedic materials such as titanium and its alloys. These topographies use high aspect ratio nanospikes or nanowires to prevent bacterial adhesion but these features puncture adhering cells, thus also reducing MSC adhesion. Here, we use a poly(ethyl acrylate) (PEA) polymer coating on titanium nanowires to spontaneously organise fibronectin (FN) and to deliver bone morphogenetic protein 2 (BMP2) to enhance MSC adhesion and osteospecific signalling. This nanotopography when combined with the PEA coating enhanced osteogenesis and reduced adhesion of Pseudomonas aeruginosa in culture. Using a novel MSC-Pseudomonas aeruginosa co-culture, we also show that the coated nanotopographies protect MSCs from cytotoxic quorum sensing and signalling molecules. We conclude that the PEA polymer-coated nanotopography can both support MSCs and prevent pathogens from adhering to a biomaterial surface, thus protecting from biofilm formation and bacterial infection and supporting osteogenic repair.

We demonstrate the formulation of advanced functional 3D printing inks that prevent the formation of bacterial biofilms in vivo. Starting from polymer libraries, we show that a biofilm resistant object can be 3D printed with the potential for shape and cell instructive function to be selected independently. When tested in vivo, the candidate materials not only resisted bacterial attachment but drove the recruitment of host defences in order to clear infection. To exemplify our approach, we manufacture a finger prosthetic and demonstrate that it resists biofilm formation – a cell instructive function that can prevent the development of infection during surgical implantation. More widely, cell instructive behaviours can be ‘dialled up’ from available libraries and may include in the future such diverse functions as the modulation of immune response and the direction of stem cell fate.Competing Interest StatementThe authors have declared no competing interest.View Full Text

SARS-CoV-2 transmission occurs via airborne droplets and surface contamination. We show tiles coated with TiO2 120 days previously can inactivate SARS-CoV-2 under ambient indoor lighting with 87% reduction in titres at 1h and complete loss by 5h exposure. TiO2 coatings could be an important tool in containing SARS-CoV-2.

Protein-based nanobubbles such as halophilic archaeabacterial gas vesicles (GVs) represent a new class of stable, homogeneous nanoparticles with acoustic properties that allow them to be visualized by ultrasound (US) waves. To design GVs as theranostic agents, we modified them to respond to light, with a view to locally generate reactive oxygen species that can kill cancer cells. Specifically, up to 60,000 photoreactive chlorin e6 (Ce6) molecules were chemically attached to lysine {varepsilon}-amino groups present on the surface of each purified Halobacterium sp. NRC-1 GV. The resulting fluorescent NRC-1 Ce6-GVs have dimensions comparable to that of native GVs and were efficiently taken up by human breast [MCF-7] and human hypopharyngeal [FaDu-GFP] cancer cells as monitored by confocal microscopy and flow cytometry. When exposed to light, internalized Ce6-GVs were 200-fold more effective on a molar basis than free Ce6 at killing cells. These results demonstrate the potential of Ce6-GVs as novel and promising nanomaterials for image-guided photodynamic therapy.

The rapid emergence of drug-resistant bacteria and fungi poses a threat for healthcare worldwide. The development of novel effective small molecule therapeutic strategies in this space has remained challenging. An orthogonal approach, therefore, is to explore biomaterials with physical modes of action which have the potential to generate antimicrobial activity and in some cases even prevent antimicrobial resistance. Here, to this effect, we describe an approach for forming silk-based films that contain embedded selenium nanoparticles. We show that these materials exhibit both antibacterial and antifungal properties while crucially also remaining highly biocompatible and non-cytotoxic towards mammalian cells. By incorporating the nanoparticles into silk films, the protein scaffold acts in a two-fold manner; it protects the mammalian cells from the cytotoxic effects of the bare nanoparticles, while also providing a template for bacterial and fungal eradication. A range of hybrid inorganic/organic films were produced and an optimum concentration was found, which allowed for both high bacterial and fungal death while also exhibiting low mammalian cell cytotoxicity. Such films can thus pave the way for next generation antimicrobial materials for applications such as wound healing and as agents against topical infections, with the added benefit that bacteria and fungi are unlikely to develop antimicrobial resistance to these hybrid materials.