Enhanced fibroblast adhesion and proliferation on electrospun fibers obtained from poly(isosorbide succinate-b-l-lactide) block copolymers

Block copolymers containing isosorbide succinate and l-lactic acid repeating units with different mass compositions were synthesized in two steps: bulk ring-opening copolymerization from l-lactide and poli(isosorbide succinate) (PIS) preoligomer, in the presence of tin(II) 2-ethylhexanoate as catalyst, followed by chain extension in solution by using hexamethylene diisocyanate. Poly(l-lactide) (PLLA) and a chain extension product from PIS were also obtained, for comparison. SEC, ¹H and ¹³C NMR, MALDI-TOFMS, WAXD, DSC, TG, and contact angle measurements were used in their characterization. The incorporation of isosorbide succinate into PLLA main backbone had minor effect on the thermal stability and the T_g of the products. However, it reduced the crystallinity and increased the surface energy in relation to PLLA. Nonwoven mats of the block copolymers and PLLA obtained by electrospinning technique were submitted to fibroblasts 3T3-L1 cell culture. The copolymers presented enhanced cell adhesion and proliferation rate as revealed by MTT assay and SEM images.