Water-Based Black Phosphorus Hybrid Nanosheets as a Moldable Platform for Wound Healing Applications.

Black phosphorus (BP) nanosheets with unique biocompatibility and superior optical performance have attracted enormous attention in material science. However, their instability and poor solution-processability severely limit their clinical applications. In this work, we demonstrate the use of silk fibroin (SF) as an exfoliating agent to produce thin-layer BP nanosheets with long-term stability and facile solution-processability. Presence of SF prevents rapid oxidation and degradation of the resultant BP nanosheets, enhancing their performance in physiological environment. The SF-modified BP nanosheets exhibit subtle solution-processability and are fabricated into various BP-based material formats. As superior photothermal agents, BP-based wound dressings effectively prevent bacterial infection and promote wound repair. Therefore, this work opens new avenues for unlocking current challenges of BP nanosheet applications for practical biomedical purposes.

A black phosphorus nanosheet-based siRNA delivery system for synergistic photothermal and gene therapy.

Gene therapy with small interfering RNA (siRNA) has been proved to be a promising technology to treat various diseases by hampering the production of target proteins. However, developing a delivery system that has high efficiency in transporting siRNA without obvious side effects remains a challenge. Herein, we designed a new survivin siRNA delivery system based on polyethyleneimine functionalized black phosphorus (BP) nanosheets which could suppress tumor growth by silencing survivin expression. Combined with the photothermal properties of the BP nanosheets, the presented delivery system shows excellent therapy efficiency for tumors. Therefore, the BP-based delivery system would be a promising tool for future clinical applications.

Silk fibroin-assisted exfoliation and functionalization of transition metal dichalcogenide nanosheets for antibacterial wound dressings.

Two-dimensional transition metal dichalcogenides (TMDs) have attracted rapidly increasing attention due to their fascinating properties and potential applications. However, scalable and cost-effective methods to produce thin-layer TMD nanosheets and their functional composites with environmental benignity are still limited. Herein, we develop a facile and environmentally friendly method for the scalable production of thin-layer TMD nanosheets in an aqueous medium by using silk fibroin, a natural and abundant biopolymer, as the exfoliating agent. Specifically, carboxyl-modified silk fibroin significantly improves the exfoliation efficiency, achieving the high-yield production of thin-layer MoSe2 nanosheets with good solution stabilization and excellent biocompatibility. Strong binding interactions endow the resultant MoSe2 nanosheets with unprecedentedly high concentrations. By virtue of the solution-processability of silk fibroin, MoSe2 hybrid nanosheets are readily fabricated into macroscopic freestanding films. Furthermore, due to the superior peroxidase-like activity of MoSe2 nanosheets, MoSe2-based films show rapid and effective wound disinfection and healing efficacy with the use of low-dose H2O2in vivo, avoiding the side effects of high-dose H2O2 in traditional medical therapy. This work may offer new opportunities to apply two-dimensional TMD nanosheets for clinical applications.

Monodisperse phase transfer and surface bioengineering of metal nanoparticles via a silk fibroin protein corona.

Uniform hydrophobic nanoparticles synthesized in nonpolar solvents possess excellent physio-chemical properties, showing great potential in biomedical applications. However, the presence of hydrophobic ligands on their surfaces limits their use under physiological conditions. Inspired by protein coronas present at the nano-bio interface, here we report a facile and universal method for phase transfer and surface bioengineering of hydrophobic nanoparticles using ß-sheet-rich silk fibroin, a FDA-approved natural protein. Due to its amphiphilicity and high mechanical stiffness, the ß-sheet-rich silk fibroin not only readily drags nanoparticles from an organic phase into aqueous media but also endows them with excellent monodispersity and long-term stability. The silk fibroin-coated nanoparticles can retain the magnetic and optical properties of the original nanoparticles, acting effectively as probes for biomedical imaging and biosensing. Furthermore, hydrophobic drugs can be easily adsorbed onto the protein coating via hydrophobic interaction, allowing the construction of promising theranostic nanoagents. Given these unique features, the strategy developed here possesses great promise in facilitating biomedical applications of hydrophobic nanomaterials.