Despite advances in the development of silk fibroin (SF)-based hydrogels, current methods for SF gelation show significant limitations such as lack of reversible crosslinking, use of nonphysiological conditions, and difficulties in controlling gelation time. In the present study, a strategy based on dynamic metal-ligand coordination chemistry is developed to assemble SF-based hydrogel under physiological conditions between SF microfibers (mSF) and a polysaccharide binder. The presented SF-based hydrogel exhibits shearthinning and autonomous self-healing properties, thereby enabling the filling of irregularly shaped tissue defects without gel fragmentation. A biomineralization approach is used to generate calcium phosphate-coated mSF, which is chelated by bisphosphonate ligands of the binder to form reversible crosslinkages. Robust dually crosslinked (DC) hydrogel is obtained through photopolymerization of acrylamide groups of the binder. DC SF-based hydrogel supports stem cell proliferation in vitro and accelerates bone regeneration in cranial critical size defects without any additional morphogenes delivered. The developed self-healing and photopolymerizable SF-based hydrogel possesses significant potential for bone regeneration application with the advantages of injectability and fit-to-shape molding.

Silk-based nanoparticles have been exhibiting an increasing potential for use as drug delivery systems due to their great versatility. To extend applications of silk sericin in nanomedicine and improve the performance of silk-based nanoparticles in drug delivery, a facile two-step cross-linking is attempted, for the first time, to fabricate surface charge-reversal silk sericin-based nanoparticles (SSC@NPs) by introducing chitosan into silk sericin. The results suggest stable SSC@NPs are formed with a negative surface charge in a neutral environment. Under mildly acidic conditions, however, surface charge of SSC@NPs undergoes a negative-to-positive conversion. It proves that pH can regulate surface charge of SSC@NPs. It is the increased amino/carboxyl ratio in SSC@NPs that explains the underlying mechanism of the charge conversion property of SSC@NPs. Furthermore, the positively charged SSC@NPs triggered by tumor acidic microenvironment (pH 6.0) result in a 6.0fold higher cellular uptake than the negatively charged counterparts at pH 7.4. In addition, an anticancer drug doxorubicin (DOX) is readily loaded into SSC@NPs and released in a pH-dependent manner. This work provides a simple method to fabricate smart pH-responsive nanoparticles for anticancer drug delivery.

Cellular plastics have been widely used in transportation, aerospace, and personal safety applications owing to their excellent mechanical, thermal, and acoustic properties. It is highly desirable to impart them with a complex porous structure and composition distribution to obtain specific functionality for various engineering applications, which is challenging with conventional foaming technologies. Herein, it is demonstrated that this can be achieved through the controlled freezing process of a monomer/water emulsion, followed by cryopolymerization and room temperature thawing. As ice is used as a template, this method is environmentally friendly and capable of producing cellular plastics with various microstructures by harnessing the numerous morphologies of ice crystals. In particular, a cellular plastic with a radially aligned structure shows a negative Poisson’s ratio under compression. The rigid plastic shows a much higher energy dissipation capability compared to other materials with similar negative Poisson’s ratios. Additionally, the simplicity and scalability of this approach provides new possibilities for fabricating high‐performance cellular plastics with well‐defined porous structures and composition distributions.

Pure chitosan membranes present insufficient mechanical properties and a high swelling ratio, which limits their application in biomedical field. In this study, silk microfibers were obtained by chemical hydrolysis, and a novel type of chitosan/silk microfiber (CS/mSF) blended membrane was reported and its multiple physical properties were evaluated. The mechanical properties were significantly improved after blending silk microfibers with a chitosan matrix, while the swelling ratio was decreased. Observation of the surface microstructures of the blended membranes via scanning electron microscopy showed abundant embedding of mSF into the CS matrix, as well as connections among mSF. In vitro cytocompatibility was also investigated, and the blended membranes exhibited significant cytocompatibility, which was demonstrated by cell proliferation and cell morphology. Furthermore, the in vivo healing effects of the blended membrane as a wound dressing were determined on a full-thickness skin wound model of rats.Animal studies revealed that the membranes containing mSF exhibited increased wound healing efficiency compared with pure CS membranes and treatment without wound dressing. From an examination of histological changes, a higher level of epithelialization and collagen formation was observed with treatment of CS/mSF blended membranes after a 21 day repair period. In conclusion, our results indicated that the blended membranes with CS and mSF might be a potential candidate material for wound healing.