Efficient Light-Based Bioprinting via Rutin Nanoparticle Photoinhibitor for Advanced Biomedical Applications.

Digital light processing (DLP) bioprinting, known for its high resolution and speed, enables the precise spatial arrangement of biomaterials and has become integral to advancing tissue engineering and regenerative medicine. Nevertheless, inherent light scattering presents significant challenges to the fidelity of the manufactured structures. Herein, we introduce a photoinhibition strategy based on Rutin nanoparticles (Rnps), attenuating the scattering effect through concurrent photoabsorption and free radical reaction. Compared to the widely utilized biocompatible photoabsorber tartrazine (Tar), Rnps-infused bioink enhanced printing speed (1.9×), interlayer homogeneity (58% less overexposure), resolution (38.3% improvement), and print tolerance (3× high-precision range) to minimize trial-and-error. The biocompatible and antioxidative Rnps significantly improved cytocompatibility and exhibited resistance to oxidative stress-induced damage in printed constructs, as demonstrated with human induced pluripotent stem cell-derived endothelial cells (hiPSC-ECs). The related properties of Rnps facilitate the facile fabrication of multimaterial, heterogeneous, and cell-laden biomimetic constructs with intricate structures. The developed photoinhibitor, with its profound adaptability, promises wide biomedical applications tailored to specific biological requirements.

Micro-nanofiber composite biomimetic conduits promote long-gap peripheral nerve regeneration in canine models.

Peripheral nerve injuries may result in severe long-gap interruptions that are challenging to repair. Autografting is the gold standard surgical approach for repairing long-gap nerve injuries but can result in prominent donor-site complications. Instead, imitating the native neural microarchitecture using synthetic conduits is expected to offer an alternative strategy for improving nerve regeneration. Here, we designed nerve conduits composed of high-resolution anisotropic microfiber grid-cordes with randomly organized nanofiber sheaths to interrogate the positive effects of these biomimetic structures on peripheral nerve regeneration. Anisotropic microfiber-grids demonstrated the capacity to directionally guide Schwann cells and neurites. Nanofiber sheaths conveyed adequate elasticity and permeability, whilst exhibiting a barrier function against the infiltration of fibroblasts. We then used the composite nerve conduits bridge 30-mm long sciatic nerve defects in canine models. At 12 months post-implant, the morphometric and histological recovery, gait recovery, electrophysiological function, and degree of muscle atrophy were assessed. The newly regenerated nerve tissue that formed within the composite nerve conduits showed restored neurological functions that were superior compared to sheaths-only scaffolds and Neurolac nerve conduit controls. Our findings demonstrate the feasibility of using synthetic biophysical cues to effectively bridge long-gap peripheral nerve injuries and indicates the promising clinical application prospects of biomimetic composite nerve conduits.

The effects of pulsed electromagnetic fields combined with a static magnetic intramedullary implant on the repair of bone defects: A preliminary study.

There is a basic consensus on the biological effects of pulsed electromagnetic fields (PEMFs) on bone formation and bone reconstruction. PEMFs have been widely used in clinical treatment of osteoporosis, bone nonunion and delayed fracture healing. PEMFs is an intervention method of physiotherapy in vitro. In order to optimize the effect of PEMFs intervention, this study combined with the orthopedics clinic to construct a static magnetic intramedullary implant using NdFeB magnets as components. At the same time, it combines external-pulsed electromagnetic field to achieve locally targeted magnetic microenvironment. Rabbits were randomly divided into a combined magnetic field group (Implantation of static magnetic intramedullary implant in vivo combined with external-pulsed electromagnetic field), pulsed electromagnetic field group and control group. Micro CT and histopathology were used to estimate the effect of each group on bone formation and reconstruction in the early stage (5 weeks) of bone defect repair. Our data showed that the combined magnetic field group had relatively better new bone volume and trabecular structure in the bone defect area. The results showed that the combined magnetic field intervention method was feasible and had relatively preferably osteogenesis promoting effect. This study provides a new idea of magnetic field intervention, and also preliminarily verifies the feasibility of adding magnetic field to traditional orthopedic implant materials. However, the magnetic field strength of implanted materials still needs to be further refined.