Injectable Bombyx mori (B. mori) silk fibroin/MXene conductive hydrogel for electrically stimulating neural stem cells into neurons for treating brain damage.

Brain damage is a common tissue damage caused by trauma or diseases, which can be life-threatening. Stem cell implantation is an emerging strategy treating brain damage. The stem cell is commonly embedded in a matrix material for implantation, which protects stem cell and induces cell differentiation. Cell differentiation induction by this material is decisive in the effectiveness of this treatment strategy. In this work, we present an injectable fibroin/MXene conductive hydrogel as stem cell carrier, which further enables in-vivo electrical stimulation upon stem cells implanted into damaged brain tissue. Cell differentiation characterization of stem cell showed high effectiveness of electrical stimulation in this system, which is comparable to pure conductive membrane. Axon growth density of the newly differentiated neurons increased by 290% and axon length by 320%. In addition, unfavored astrocyte differentiation is minimized. The therapeutic effect of this system is proved through traumatic brain injury model on rats. Combined with in vivo electrical stimulation, cavities formation is reduced after traumatic brain injury, and rat motor function recovery is significantly promoted.

Hierarchically patterned protein scaffolds with nano-fibrillar and micro-lamellar structures modulate neural stem cell homing and promote neuronal differentiation.

Biophysical factors are essential in cell survival and behaviors, but constructing a suitable 3D microenvironment for the recruitment of stem cells and exerting their physiological functions remain a daunting challenge. Here, we present a novel silk fibroin (SF)-based fabrication strategy to develop hierarchical microchannel scaffolds for biomimetic nerve microenvironments in vitro. We first modulated the formation of SF nanofibers (SFNFs) that mimic the nanostructures of the native extracellular matrix (ECM) by using graphene oxide (GO) nanosheets as templates. Then, SFNF-GO systems were shaped into 3D porous scaffolds with aligned micro-lamellar structures by freeze-casting. The interconnected microchannels successfully induced cell infiltration and migration to the SFNF-GO scaffolds' interior. Meanwhile, the nano-fibrillar structures and the GO component significantly induced neural stem cells (NSCs) to differentiate into neurons within a short timeframe of 14 d. Importantly, these 3D hierarchical scaffolds induced a mild inflammatory response, extensive cell recruitment, and effective stimulation of NSC neuronal differentiation when implanted in vivo. Therefore, these SFNF-GO lamellar scaffolds with distinctive nano-/micro-topographies hold promise in the fields of nerve injury repair and regenerative medicine.

Silk Protein-Mediated Biomineralization: From Bioinspired Strategies and Advanced Functions to Biomedical Applications.

Biomineralization refers to the process through which minerals nucleate in a structured manner to form specific crystal structures by the regulating of biomacromolecules. Biomineralization occurs in bones and teeth within the human body, where collagen acts as a template for the nucleation of hydroxyapatite (HA) crystals. Similar to collagen, silk proteins spun by silkworms can also serve as templates for the nucleation and growth of inorganic substances at interfaces. By enabling the binding of silk proteins to inorganic minerals, the process of biomineralization enhances the properties of silk-based materials and broadens their potential applications, rendering them highly promising for use in biomedical applications. In recent years, the development of biomineralized materials using silk proteins has garnered considerable attention in the biomedical field. This comprehensive review outlines the mechanism of biomineral formation mediated by silk proteins, as well as various biomineralization methods used to prepare silk-based biomineralized materials (SBBMs). Additionally, we discuss the physicochemical properties and biological functions of SBBMs, and their potential applications in various fields such as bioimaging, cancer therapy, antibacterial treatments, tissue engineering, and drug delivery. In conclusion, this review highlights the significant role that SBBMs can play in the biomedical field.

Novel Ag-coated nanofibers prepared by electrospraying as a SERS platform for ultrasensitive and selective detection of nitrite in food.

Nitrite is commonly used as a preservative and color fixative in the meat industry. However, the risk of it transforming into N-nitrosamine restricts its intake. Herein, a novel sensitive Ag-coated nanofiber surface-enhanced Raman scattering (SERS) platform was developed for rapid nitrite detection. The electrospraying technique was firstly used to assemble Ag nanoparticles (NPs) on the nanofibers to obtaine SERS platform. The homogeneity and long-term stability of the SERS platform were evaluated. The limit of detection (LOD) of the SERS platform was estimated to be 2.216 × 10-12 mol/L, corresponding to 15.29 ng·L-1 and good linearity was shown between the relative SERS intensity and nitrite concentration range of 10-1 to 10-4 mol/L. The Ag-coated nanofiber SERS platform was utilized to assay-five common nitrite foods, and the results provided valid evidence for the compatibility of SERS platform in quantitative nitrite detection.