Biomimetic electrospun PVDF/self-assembling peptide piezoelectric scaffolds for neural stem cell transplantation in neural tissue engineering

Piezoelectric materials can provide in situ electrical stimulation without external chemical or physical support, opening new frontiers for future bioelectric therapies. Polyvinylidene fluoride (PVDF) possesses piezoelectricity and biocompatibility, making it an electroactive biomaterial capable of enhancing bioactivity through instantaneous electrical stimulation, which indicates significant potential in tissue engineering. In this study, we developed electroactive and biomimetic scaffolds made of electrospun PVDF and self-assembling peptides (SAPs) to enhance stem cell transplantation for spinal cord injury regeneration. We investigated the morphology and crystalline polymorphs of the electrospun scaffolds. Morphological studies demonstrated the benefit of using mixed sodium dodecyl sulfate (SDS) and SAPs as additives to form thinner, uniform, and defect-free fibers. Regarding electroactive phases, β and γ phases-evidence of electroactivity-were predominant in aligned scaffolds and scaffolds modified with SDS and SAPs. In vitro studies showed that neural stem cells (NSCs) seeded on electrospun PVDF with additives exhibited desirable proliferation and differentiation compared to the gold standard. Furthermore, the orientation of the fibers influenced scaffold topography, resulting in a higher degree of cell orientation in fiber-aligned scaffolds compared to randomly oriented ones.

Application of a degradable thin film to modulate perfusion to post-autotransplantation airways in rats

Objective

Recipients of lung transplants experience the lowest long-term survival among all solid-organ transplant recipients. Airway complications contribute significantly to morbidity and mortality post-lung transplant and may be driven by airway devascularization inherent to procurement and implantation of the lungs. We studied application of biodegradable, nanofiber-based thin films to devascularized autotransplanted airways to mitigate airway ischemia.

Methods

We used a rat tracheal autotransplantation model that replicates airway ischemia. Rats were divided into an operated control group (n = 18) and a treatment group (n = 12) receiving an electrospun film composed of randomly aligned polydioxanone (PDO) nanofibers applied to the circumferential surface of the transplanted trachea. Airway perfusion was assessed via laser speckle contrast analysis at 0, 3, and 10 days. Differences in perfusion units were calculated between the nontransplanted and transplanted segments of the trachea. Multimodal analysis of angiogenesis in tracheal autografts included immunoassay profiling for proangiogenic cytokines, histologic injury grading, and speckle angiography.

Results

Qualitative and quantitative perfusion differences were demonstrated at days 0, 3, and 10. Nanofiber-based, PDO thin films significantly improved perfusion in the transplanted segment of trachea (P < .05). Histologic injury scoring was significantly worse in the operated controls compared with the treatment group (P < .01). Immunoassays demonstrated increased expression of vascular cell adhesion molecule 1 in the treatment group (P < .05).

Conclusions

Application of a nanofiber-based, PDO thin film induced a local tissue response that improved perfusion and histologic injury scoring of the transplanted airway in an autotransplant model of airway devascularization. Immune multiplexing suggests local inflammatory responses may drive angiogenesis.