Interest is rapidly growing in the design and preparation of bioactive scaffolds, mimicking the biochemical composition and physical microstructure for tissue repair. In this study, a biomimetic biomaterial with nanofibrous architecture composed of silk fibroin and hyaluronic acid (HA) was prepared. Silk fibroin nanofiber was firstly assembled in water and then used as the nanostructural cue; after blending with hyaluronan (silk:HA = 10:1) and the process of freeze-drying, the resulting composite scaffolds exhibited a desirable 3D porous structure and specific nanofiber features. These scaffolds were very porous with the porosity up to 99%. The mean compressive modulus of silk-HA scaffolds with HA MW of 0.6, 1.6, and 2.6 × 10⁶ Da was about 28.3, 30.2, and 29.8 kPa, respectively, all these values were much higher than that of pure silk scaffold (27.5 kPa). This scaffold showed good biocompatibility with bone marrow mesenchymal stem cells, and it enhanced the cellular proliferation significantly when compared with the plain silk fibroin. Collectively, the silk-hyaluronan composite scaffold with a nanofibrous structure and good biocompatibility was successfully prepared, which deserved further exploration as a biomimetic platform for mesenchymal stem cell-based therapy for tissue repair.

Photo-cross-linkable hydrogels have recently gained increased interest in the field of biomedical applications. In this study, silk fibroin was derivatized with methacrylic anhydride (MA) to obtain silk fibroin methacryloyl (SFMA), forming hydrogel under UV light exposure in 1 min. The SFMA sol-gel transition did not involve significant structural change at the early stage. Then, the formation of the irreversible β-sheet was confirmed after 24 h. The resulting SFMA hydrogel showed a homogeneous porous structure with pore sizes ranging from 400 to 700 μm, depending on the content. In addition, these hydrogels demonstrated a lower swelling capacity, higher rheological properties and compressive modulus, and slow degradation behavior at higher content, likely due to the higher degree of cross-linking. An experiment with cells indicated the good cell compatibility of these hydrogels, as revealed by Cell Counting Kit-8 (CCK-8) assays. As a tissue-engineered material, this photo-cross-linkable SFMA is expected to have a wide range of applications in the biomedical field.

The possibility of using nonmulberry silk fibroin as a biomaterial is a subject of broad interest due to its inherent RGD sequence. However, the extraction of silk fibroin from cocoons and silk glands remains a formidable task. In this work, we report a facile method to dissolve tussah silk using CaCl₂–formic acid and a water-rinsing process for regeneration of tussah silk fibroin (TSF) film. The new technique is important and valuable because it can directly extract silk fibroin from cocoons and is advantageous over other previous reported methods using LiSCN and Ca(NO₃)₂. The morphology, chemical structure, and mechanical properties of regenerated film rinsed with water, ethanol, and methanol are characterized by scanning electron microscopy, Fourier transform infrared, and X-ray diffraction techniques in combination with mechanical testing. The results reveal that the regenerated TSF films possess a smooth surface and nanostructural cross section and exhibit predominantly β-sheet crystal structure and good mechanical properties in wet state. In addition, enhanced cell attachment and proliferation of bone marrow stem cells are observed on water-rinsed TSF film. The present study provides a novel way for dissolution and regeneration of tussah silk, and the resulting TSF films are a promising biomaterial for tissue engineering applications.

Nrf2 is a critical regulator of the antioxidant defense systems in cellular protection. Emerging evidence has shown that four‐octyl itaconate (OI) activates Nrf2 cascade. In this study, the chondroprotective effects of OI on H₂O₂‐stimulated chondrocytes and DMM‐induced osteoarthritis (OA) progression were investigated. In primary murine chondrocytes, OI interrupted the binding of Keap1 and Nrf2, leading to accumulation and nuclear translocation of Nrf2 protein, as well as transcription and expression of Nrf2‐dependent genes, such as HO-1, NQO1, and GCLC. Furthermore, OI inhibited cell death and apoptosis, as well as H₂O₂‐stimulated ROS generation, lipid peroxidation, superoxide accumulation, and mitochondrial depolarization in chondrocytes, which were abolished by the silence or depletion of Nrf2. In addition, in vivo experiments revealed the therapeutic effects of OI on OA progression in a DMM mouse model. Collectively, these results suggested that OI might serve as a potential treatment for OA progression.

Staphylococcus aureus is a significant cause of foodborne illness in China. Our investigation concentrated on the genetic characterization of foodborne S. aureus identified during unannounced inspections conducted in Suzhou from 2012 to 2021. Dominant clones included CC1, CC398, CC188, and CC7, with CC398 notably increasing in 2020–2021. The isolates commonly contained 1–3 plasmids, with rep_5a (48.55%) and rep₁₆ (44.51%) predominating. A concerning 24.3% showed multi-drug resistance, particularly to penam (blaZ, mecA) and fosfomycin (fosB), with resistance rates rising from 32.7% to 53.3%, potentially linked to the increase in CC types like CC5, CC20, and CC25. Most isolates carried genes for virulence factors such as aureolysin, hemolysin, staphylokinase, and staphylococcal complement inhibitor. A significant increase in virulence genes, especially the enterotoxin gene sea, was observed, possibly associated with shifts in CC1 and CC7 prevalence. This underscores the necessity for ongoing surveillance to understand genomic traits of S. aureus in ensuring food safety.

Objectives: To investigate the distribution and function of olfactory ensheathing cells (OECs) following lumbar puncture (LP) transplantation in mouse spinal cord injury (SCI). Methods: OECs were transplanted by LP at level L3–5, 1 week after transected SCI at T8 vertebra. Mice were killed at 3, 21, and 56 days after LP transplantation, and the relative distribution of cells at T8 vertebra was quantitated. The injured spine was also tested by immunohistochemistry to assess neuron regeneration and scar bridging at 8 weeks posttransplantation. Motor functions of mice were evaluated during the observation period using the Basso Mouse Scale. Results: OECs were examined and confirmed by studying cell morphology under phase contrast and immunostaining of NGFR p75. LP-transplanted OECs could be detected just 3 days after transplantation (p75⁺ area: 0.16 mm²) and accumulated to 0.31 and 0.30 mm² at 21 and 56 days postengraftment, respectively. The number of endogenous neurons, −400 to +400 µm, far from the epicenter, in OEC-transplanted mice was more than that in SCI mice without engraftment. SCI lesion of mice in the control group (164.3±3.97 µm) was much longer than that in OEC-grafted group (116.7±3.60 µm). Grafts of OECs induced significant functional improvement in mice that underwent T8 vertebral transection, just from 3 days after cell injection. Conclusion: LP is a minimally invasive method for OEC transplantation to treat SCI. This is the first study to visualize the distribution and functions of LP-transplanted OECs in the intact and injured spinal cord.