Fabrication and sustained-release characterization of a TRPC3-inhibitor-loaded electrospun PVA nanofiber scaffold

Purpose Electrospun nanofiber scaffolds are an appealing platform for localized small-molecule delivery, but burst release from hydrophilic polymers such as polyvinyl alcohol (PVA) limits their utility for sustained pharmacologic exposure. In this proof-of-concept study, we developed and characterized a fabrication protocol for PVA nanofiber scaffolds (NFSs) loaded with a novel selective transient receptor potential canonical 3 (TRPC3) inhibitor to determine whether the inhibitor can be incorporated into an electrospun PVA scaffold without disrupting the fiber architecture and evaluate the impact of thermal crosslinking on the release characteristics. The biological activity of this TRPC3 inhibitor in diabetic dermal fibroblasts was characterized previously by our group; the present study addresses the prerequisite engineering before in vitro and in vivo evaluation of the NFS. Methods NFSs were fabricated by blend electrospinning of PVA with a selective TRPC3 inhibitor. NFSs were thermally crosslinked at 130 °C and 160 °C for 30, 60, and 120 min. Fiber morphology was characterized by scanning electron microscopy (SEM) with automated diameter analysis. Drug release was quantified by LC–MS triple quadrupole at 30 min and 24 h. Results SEM confirmed uniform bead-free nanofibers with preserved architecture following drug incorporation (drug-free 160.0 ± 78.3 nm and drug-loaded 191.6 ± 100.0 nm; p < 0.001). Reduced syringe speed increased the mean fiber diameter from 114.2 ± 60.7 nm to 157.3 ± 76.2 nm (p < 0.001). Thermal crosslinking produced temperature- and duration-dependent fiber diameter changes (p < 0.001). Crosslinked scaffolds released 213 nM of TRPC3 inhibitor at 30 min and 335 nM at 24 h (cumulative loading 654.3 pmol/cm 2 ), demonstrating sustained release. Non-crosslinked scaffolds exhibited burst release with no appreciable accumulation between the time-points (93 nM at 30 min and 90 nM at 24 h; cumulative loading 179.3 pmol/cm 2 ). Conclusion A novel selective TRPC3 inhibitor was successfully incorporated into a PVA-based electrospun nanofiber scaffold without disruption of the fiber architecture, and thermal crosslinking converted the burst-release behavior typical of PVA into sustained release over a 24-h interval. These findings establish the fabrication and release characteristics of this drug–scaffold combination as the prerequisite foundation for subsequent in vitro and in vivo evaluation in diabetic wound-healing models.