Electrospun poly(hydroxybutyrate-co-hydroxyvalerate) fibrous membranes consisting of parallel-aligned fibers or cross-aligned fibers: characterization and biological evaluation.

Poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) fibrous membranes consisting of parallel-aligned fibers or cross-aligned fibers were fabricated through electrospinning with the help of a rotating cylinder as fiber collector and auxiliary electrodes, and their application as tissue-engineering scaffolds was assessed. First, these membranes were characterized in terms of fiber diameter, spacing between adjacent aligned fibers or interstitial pore diameter, degree of fiber alignment, wettability and tensile properties. Then, human osteoblast-like cells (SaOS-2) were seeded and cultured on these membranes for up to 14 days. The cell morphology and proliferation were evaluated at different cell culture times. Membranes consisting of random fibers or parallel-aligned fibers were obtained when the rotational speed of the cylinder was 500 rpm or 3000 rpm, respectively. A very high rotational speed of 15 000 rpm resulted in the formation of parallel-aligned fibers having low or no spacing between the aligned fibers. Membranes consisting of cross-aligned fibers were made at the rotational speed of 3000 rpm and micrometer-sized fiber spacing was observed in these membranes. The alignment of fibers led to enhanced wettability of fibrous membranes. Tensile testing revealed that the parallel-aligned fibrous membranes were strong in the longitudinal direction but weak in the transverse direction. The cross-aligned fibrous membranes did not exhibit particularly weak tensile properties in any direction. In vitro biological evaluation showed that SaOS-2 cells spread randomly on membranes of random fibers but elongated in membranes of aligned fibers. All membranes supported cell proliferation in spite of the differences in cell morphology.