Abstract
Poly(e-caprolactone) (PCL) and its block copolymers with poly(ethylene glycol) (PEG) were prepared by ring-opening polymerization of e-caprolactone in the presence of ethylene glycol or PEG, using zinc metal as catalyst. The resulting polymers were characterized by various analytical techniques such as 1H NMR, SEC, DSC, IR, X-ray, ESEM, and CZE. PCL/PEG copolymers with long PCL chains presented the same crystalline structure as PCL homopolymer, while PEG bearing short PCL blocks retained the crystalline structure of PEG and exhibited an amphiphilic behavior in aqueous solutions. Degradation of PCL and PCL/PEG diblock and triblock copolymers was realized in a 0.13M, pH 7.4 phosphate buffer at 37°C. The results indicated that the copolymers exhibited higher hydrophilicity and degradability as compared with the PCL homopolymer. Large amounts of PEG were released from the bulk after 60 weeks degradation. In vitro cell culture studies were conducted on scaffolds manufactured via solid free form fabrication by using primary human and rat bone marrow derived stromal cells (hMSC, rMSC). Light, scanning electron, and confocal laser microscopy as well as immunocytochemistry showed cell attachment, proliferation and extracellular matrix production on the surface as well as inside the scaffold architecture. Copolymers showed better performance in the cell culture studies than the PCL homopolymer.