Electrospinning of poly(β-hydroxybutyrate) scaffolds: morphology and aging

Fibrous polymeric scaffolds that comprise capabilities of biomimicry to the native tissue architecture and achieve functional tissue-engineered products with minimal surgical implantation. This research focused on the production of fibrous scaffolds of biodegradable microbial poly(β-hydroxybutyrate) (PHB) by electrospinning. Processing conditions were found to influence the morphology of the scaffolds, which, in turn, controlled the wettability and aging behavior, quite important for medical applications. Commercial and biosynthesized PHB from a mutant Azotobacter vinelandii OP strain were investigated. The morphology and wettability of the fibrous scaffolds were characterized using optical, atomic and scanning electron microscopy. Tuning the voltage and the solution concentration (at constant flow rate) produced either a filamentous morphology or aggregates of filaments. The wettability correlated with the degree of porosity, and predominantly a hydrophobic behavior was attained in an otherwise hydrophilic material. Aging, monitored at room temperature up to 11 months by degree of crystallinity, α, showed that scaffolds with filamentous morphology exhibited an increase in crystallinity, leading to brittleness. However, scaffolds with aggregated filaments were quite stable as the degree of crystallinity remained constant over the 11-month period. Applications are envisioned for PHB biomimetic scaffolds in cell growth and bone tissue regeneration.