Fabrication of Aligned Polyhydroxybutyrate Fibrous Scaffolds via a Touchspinning Apparatus

Poly-(3-hydroxybutyrate) (PHB) fibers ranging from nano- to microscale were successfully fabricated using a touchspinning apparatus. The optimization of key spinning parametersincluding solution concentration (5-11% w/v), rotational speed (1300-2100 rpm), and feed rate (5-20 μL/min)enabled the production of aligned fibrous scaffolds. Morphological analysis via field emission scanning electron microscopy (FE-SEM) revealed fiber diameters in the range of 0.831-1.273 μm, which were influenced by spinning conditions. Thermal stability was confirmed using thermogravimetric analysis (TGA), with an onset degradation temperature of ∼290 °C. Differential scanning calorimetry (DSC) showed a melting peak of ∼172 °C and a crystallinity increase from 37.9% in the pellet to 42.5% in fibers of PHB. The scaffolds were functionalized with collagen to enhance bioactivity, and fibroblast (NIH3T3) viability was assessed through alamarBlue and Live/Dead assays. Metabolic activity increased significantly over 5 days (p < 0.05), particularly in collagen-modified scaffolds, confirming excellent cell adhesion and proliferation. Immunofluorescent microscopy demonstrated cell elongation along the fiber axis, indicating scaffold-guided cellular orientation. The results establish the feasibility of touchspun PHB scaffolds for tissue engineering applications, offering a scalable alternative to the conventional electrospinning process.