The use of antimicrobial materials, for example, silver nanoparticles, has been a cause for concern because they often exert an adverse effect on environmental and safety during their preparation and use. In this study, we report a class of green antimicrobial coating based on a supramolecular assembly of a protein extracted from daily food, without the addition of any other hazardous agents. It is found that a self-assembled nanofilm by mere hen egg white lysozyme has durable in vitro and in vivo broad-spectrum antimicrobial efficacy against Gram-positive/negative and fungi. Such enhanced antimicrobial capability over native lysozyme is attributed to a synergistic combination of positive charge and hydrophobic amino acid residues enriched on polymeric aggregates in the lysozyme nanofilm. Accompanied with high antimicrobial activity, this protein-based PTL material simultaneously exhibits the integration of multiple functions including antifouling, antibiofilm, blood compatibility, and low cytotoxicity due to the existence of surface hydration effect. Moreover, the bioinspired adhesion mediated by the amyloid structure contained in the nanofilm induces robust transfer and self-adhesion of the material onto virtually arbitrary substrates by a simple one-step aqueous coating or solvent-free printing in 1 min, thereby allowing an ultrafast route into practical implications for surface-functionalized commodity and biomedical devices. Our results demonstrate that the application of pure proteinaceous substance may afford a cost-effective green biomaterial that has high antimicrobial activity and low environmental impact.Keywords: antimicrobial; biocompatibility; lysozyme; protein phase transition; surface coating;

•Ti substrates were treated by electrochemical anodization and LBL self-assembly.•This drug/device combination stimulated the biological responses of osteoblast.•This system imposed antibacterial property on Ti substrates.•Modified Ti substrates have potential application in orthopedic field.The insufficient osseointegration and bacterial infection of titanium and its alloys remain the key challenges in their clinic applications, which may result in failure implantation. To improve osteogenetic and antibacterial properties, TiO2 nanotube arrays were fabricated on titanium substrates for loading of antibacterial drug. Then, TiO2 nanotube arrays were covered with chitosan/sodium alginate multilayer films. The successful construction of this system was verified via scanning electron microscopy and contact angle measurement. The cytocompatibility evaluation in vitro, including cytoskeleton observation, cell viability measurement, and alkaline phosphatase activity assay, confirmed that the present system was capable of accelerating the growth of osteoblasts. In addition, bacterial adhesion and viability assay verified that treated Ti substrates were capable of reducing the adhesion of bacteria. This study may provide an alternative to develop titanium-based implants for enhanced bone osseointegration and reduced bacterial infection.Osteogenetic and antibacterial surfaces were constructed on Ti substrates.Download high-res image (101KB)Download full-size image

•Antibacterial surface was fabricated by a simple one-step co-deposition process.•The modified substrates showed excellent antibacterial property.•The study affords an efficient method for the fabrication of antibacterial surface.In this study, a simple one-step co-deposition process was introduced to fabricate antibacterial surfaces for synthetic materials via UV-inducing dopamine polymerization combined with in situ formation of Ag nanoparticles. The successful formation of a composite coating was demonstrated by scanning electron microscopy. Antibacterial experiments including antibacterial rate test and bacteria adhesion were evaluated in vitro. The results confirmed the excellent antibacterial property of this surface modification process. In conclusion, the approach presented here provides a simple and effective approach to construct antibacterial surfaces for synthetic materials to meet the requirements of daily life and industry application.

•Biofunctional multilayer films mimicking extracellular microenvironment were successfully fabricated.•Multilayered structure stimulated the biological responses of endothelial cells.•The approach affords an efficient approach for surface endothelialization of stent implant.To mimic extracellular microenvironment of endothelial cell, a bioactive multilayered structure of gelatin/chitosan pair, embedding with vascular endothelial growth factor (VEGF), was constructed onto NiTi alloy substrate surface via a layer-by-layer assembly technique. The successful fabrication of the multilayered structure was demonstrated by scanning electron microscopy, atomic force microscopy, contact angle measurement, attenuated total reflection-fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy, respectively. The growth behaviors of endothelial cells on various NiTi alloy substrates were investigated in vitro. Cytoskeleton observation, MTT assay, and wound healing assay proved that the VEGF-embedded multilayer structure positively stimulated adhesion, proliferation and motogenic responses of endothelial cells. More importantly, the present system promoted the nitric oxide production of endothelial cells. The approach affords an alternative to construct extracellular microenvironment for improving surface endothelialization of a cardiovascular implant.

•Cathodic plasma electrolysis was used to construct ZrO2 coating on magnesium alloy.•Corrosion resistance of magnesium alloy was significantly improved.•Surface functionalization of magnesium alloy via this process was beneficial for cell growth.To improve corrosion resistance and enhance biocompatibility of magnesium alloy, cathodic plasma electrolysis (CPE), a liquid phase plasma technique, was used to fabricate zirconia (ZrO2) coatings onto WE43 magnesium alloy substrate. Surface morphology and phase composition of the coatings on magnesium alloy substrates were investigated by scanning electron microscope (SEM) and X-ray diffraction (XRD), respectively. The potentiodynamic polarization test in simulated body fluid (SBF) indicated that corrosion resistance of magnesium alloy was significantly improved by this CPE treatment. The results of cytocompatibility including osteoblasts adhesion and viability suggested that surface modification of magnesium alloy with ZrO2 coating fo’rmed via CPE technique is beneficial for cell proliferation and differentiation. The approach presented here should be an attractive way for surface modification of magnesium-based implants to improve anticorrosion and bone osseointegration.

To enhance corrosion resistance of WE43 magnesium alloy, chitosan (CHI) and poly (styrene sulfonate) (PSS) polyelectrolyte multilayers were fabricated on micro-arc oxidation (MAO) treated magnesium alloy substrate via layer-by-layer (LBL) self-assembly technique. Surface morphology and chemical composition of the MAO/LBL composite coating were investigated by scanning electron microscopy (SEM), atomic force microscope (AFM) and X-ray photoelectron spectroscopy (XPS), respectively. Potentiodynamic polarization test and hydrogen evolution measurement showed that the formed MAO/LBL coating significantly enhanced corrosion resistance of WE43 magnesium alloy in simulated body fluid (SBF). The approach presented here affords an effective alternative for surface modification of magnesium-based materials to meet the requirements of biomaterials applications.Highlights► Polyelectrolyte multilayers were fabricated on WE43 magnesium. ► The corrosion resistance of WE43 magnesium alloy was significantly improved. ► The approach affords an efficient method for surface modification of Mg alloy.

To improve surface endothelialization of NiTi alloy substrate, a nano-structured coating functionalized with vascular endothelial growth factor (VEGF) was fabricated via polydopamine (PDOP) as intermediate layer. The successful preparation of VEGF conjugated nanocoating was demonstrated by X-ray diffraction (XRD), atomic force microscope (AFM), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS), respectively. Inductively coupled plasma mass spectrometry (ICP-MS) test showed that the formed nanocoating significantly reduced the release of Ni ion from NiTi alloy in simulated body fluid. The biological behaviors of endothelial cells adhered to modified NiTi alloy substrates, including cell proliferation, cell spreading and production of nitric oxide and prostacyclin were investigated in vitro. The results suggest that surface functionalization of NiTi alloy substrate with VEGF is beneficial for cell growth. The approach presented here affords an alternative for surface modification of NiTi implants applied as heart and vascular implant devices.Graphical abstractHighlights► A nano-structured coating functionalized with vascular endothelial growth factor was fabricated on NiTi alloy via polydopamine as intermediate layer. ► The biological behaviors of endothelial cells in NiTi alloy, including cell proliferation, cell spreading, production of nitric oxide and prostacyclin were improved. ► The approach presented here affords an alternative for surface modification of NiTi implants applied as heart and vascular implant devices.