An in situ grown ultrathin and robust protein nanocoating for mitigating thromboembolic issues associated with cardiovascular medical devices.

Thromboembolism, arising from the utilization of cardiovascular medical devices, remains a prevalent issue entailing substantial morbidity and mortality. Despite the proposal of various surface modification strategies, each approach possesses inherent limitations and drawbacks. Herein, we propose a novel approach for the in situ growth of nanocoatings on various material surfaces through the cooperative assembly of silk fibroin (SF) and lysozyme. The intrinsic in situ growth characteristic enables the nanocoatings to achieve stable and uniform adherence to diverse substrate surfaces, including the inner surface of intravascular catheters, to redefine the surface properties of the material. The features of the hydrophilic and negatively charged nanocoating contribute to its antithrombotic properties, as evidenced by the reduced likelihood of platelet adhesion upon modification of the ultrathin and mechanically robust coating. In vitro assessment confirms a significant reduction in blood clot formation along with the promotion of anticoagulation. Such a SF/Ly nanocoating holds substantial promise as a surface modification strategy to enhance the hemocompatibility of medical devices and other materials that come into contact with blood, particularly in situations where medical-grade materials are temporarily unavailable, thus providing a feasible alternative.

Self-Assembled Protein Nanofilm Regulating Uniform Zn Nucleation and Deposition Enabling Long-Life Zn Anodes.

Rechargeable zinc-ion batteries (RZIBs) have gained promising attention as a feasible alternative for large-scale energy storage by the virtue of their intrinsic security, environmental benignity, low cost, and high volumetric capacity (5849 mAh cm-3 ). Nevertheless, the deep-rooted issues of dendrite formation and side reactions in unstable Zn metal anode have impeded RZIBs from being dependably deployed in their proposed applications. Herein, silk fibroin (SF) and lysozyme (ly), as natural biomacromolecules with abundant polar groups arranged in polypeptide backbones, are in situ self-assembled on the Zn anode surface to construct a homogeneous and compact protein nanofilm. Such protein nanofilm protecting layer presents a negative charge surface and significantly regulates Zn2+ deposition behavior. Meanwhile, synergistic flexible and robust features of protein nanofilm function as artificial solid electrolyte interface (SEI), accommodates the dynamic volume deformation during deposition/dissolution, and blocks corrosion of side reactions. Consequently, the electrochemical stability of protein nanofilm-modified Zn anode is greatly improved, with an excellent extended lifespan of over 1100 h at a high current density of 10 mA cm-2 and a high cycling capacity of 10 mAh cm-2 , corresponding to a high depth of discharge (83% DODZn ). Furthermore, the highly reversible Zn electrode remarkably improved the overall performance of MnO2 ||Zn full-cells.

Silk fibroin-hydroxyapatite scaffolds promote the proliferation of adipose-derived mesenchymal stem cells by activating the ERK signal.

Adipose-derived mesenchymal stem cell (Ad-MSC) with capacities of releasing trophic factors and chondrogenic differentiation was a promising candidate for tracheal reconstruction. Silk fibroin (SF)- hydroxyapatite (HA) scaffolds were fabricated by the freeze-drying method. And Ad-MSCs were co-cultured on the scaffolds for 14 days in vitro. The role of the SF-HA scaffold in regulating the adhesion, growth, and proliferation of Ad-MSCs, and its potential mechanisms were investigated. The identity of Ad-MSCs was confirmed by cell morphology, surface markers, and differentiation characteristics. Cell proliferation, viability, and morphology were observed via CCK-8, live/dead assay, and scanning electron microscopy (SEM). Gene mRNA and protein levels were examined using quantitative real-time polymerase chain reaction and western blotting, respectively. SF-HA scaffolds showed excellent properties of promoting Ad-MSCs adhesion, growth, and proliferation for at least 14 days. In the CCK-8 assay, the relative OD value of Ad-MSCs cultured on SF-HA scaffolds increased (p < 0.001). Furthermore, live/dead staining showed that the fluorescent coverage increased with time (p < 0.05). SEM also showed that 3 days after inoculation, the coverage of Ad-MSCs on the SF-HA scaffolds was 78.15%, increased to 92.91% on day 7, and reached a peak of 94.38% on day 14. Extracellular signal-regulated kinase (ERK) mRNA and phosphorylated ERK (pERK) protein expression increased at day 3 (p < 0.05), followed by a significant decline at day 7 (p < 0.05). And ERK mRNA expression was positively correlated with Ad-MSCs proliferation (p < 0.05). In summary, the SF-HA scaffold co-cultured with Ad-MSCs is a promising biomaterial for tracheal repair by activating the ERK signal pathway.

Biomimetic Amyloid-like Protein/Laponite Nanocomposite Thin Film through Regulating Protein Conformation.

The use of natural protein-based thin films has been severely limited because of their relatively low stiffness and strength compared to synthetic polymers. Although the mechanical properties of the protein-based thin films could be enhanced through blending with nanofillers, the fabrication of these materials with nanoscale-to-macroscale hierarchical architecture and robust interfacial adhesion via a facile and green method remains a challenge. Here, we prepared robust protein-based organic/inorganic nanocomposite films with a nacre-like microstructure through directly regulating protein conformation in a simple and biocompatible all-aqueous system. These films contain a high concentration of laponite (Lap) and amyloid-like phase-transited bovine serum albumin (PTB) aggregates rich in ß-sheets, which could organize Lap nanoplatelets into an intercalated and multistacked structure. In addition, the PTB aggregates present strong mechanical strength, good stability, and especially superior bioadhesion to afford strong organic/inorganic interface bonding. The resultant PTB/Lap films exhibit high Young's modulus and strength and good chemical stability (in both aqueous solution and organic solvent) and flame retardation, while they are also very transparent (maintaining more than 90% transmittance). Moreover, the film could adhere onto various substrates with robust biomimetic interfacial adhesion, and the resultant coating on glass could function as a smart window to cool down the indoor temperature. Because of their excellent performance and high versatility, the amyloid-like protein/clay nanocomposite films are expected to find broad practical applications.

Controlling Long-Distance Photoactuation with Protein Additives.

Long-distance wireless actuation indicates precise remote control over materials, sensors, and devices that are widely utilized in biomedical, defence, disaster relief, deep ocean, and outer space applications to replace human work. Unlike radio frequency (RF) control, which has low tolerance toward electromagnetic interference (EMI), light control represents a promising method to overcome EMI. Nonetheless, long-distance light-controlled wireless actuation able to compete with RF control has not been achieved until now due to the lack of highly light-sensitive actuator designs. Here, it is demonstrate that amyloid-like protein aggregates can organize photomodule single-layer reduced graphene oxide (rGO) into a well-defined multilayer stack to display long-distance photoactuation. The amyloid-like proteinaceous component docks the rGO layers together to form a hybrid film, which can reliably adhere onto various material surfaces with robust interfacial adhesion. The sensitive photothermal effect and a fast bending in 1 s to switch a circuit are achieved after forming the film on a plastic substrate and irradiating the bilayer film with a blue laser from 100 m away. A photoactuation distance of 50 km can be further extrapolated based on a commercial high-power laser. This study reveals the great potential of amyloid-like aggregates in remote light control of robots and devices.