S. Zhong, J.J. Wang, C.X. Wu, A.L. Zhang, T.T. Zhuang, Y.F. Shi, B.H. Luo, S.Q. Tang, X.Y. Wang
ABB EL Corporation Research Center,
Keywords: drug delivery, biomaterial, hydrogel, thermogel, copolymer, TOSUO, crystallinity and rheology
Summary:Copolymer poly(ε-caprolactone-co-1, 4, 8-trioxa[4, 6]spiro-9-undecanone)-poly(ethylene glycol)-poly(ε-caprolactone-co-1, 4, 8-trioxa[4, 6]spiro-9-undecanone) briefed as poly(CL-co-TOSUO)-PEG-poly(CL-co-TOSUO) (PCT-PEG-PCT) has been successfully synthesized via ring opening polymerization (ROP). By adjusting the initial monomer feeding ratio, TOSUO molar content in the hydrophobic block increases from 0% to 20% while the repeat units of both hydrophobic and hydrophilic blocks remain the same. The analysis on the copolymers shows that TOSUO units disrupt the crystal structure in hydrophobic PCT block, and thus reduces its crystallinity and subsequently the hydrophobicity of the copolymer. As a result, the properties of copolymer aqueous thermogels are affected. The introduction of TOSUO component improves the sol stability and reduces the gelation temperature to below 37 degree C, suggesting its potential applications in injectable drug delivery/therapy. The study also indicates that one is able to tune the gel properties by de-novo designing copolymer chemistry to meet application demand.