Ž . Materials Science and Engineering C 11 2000 57–60 www.elsevier.comrlocatermsec New tissue engineering material copolymers of derivatives of cellulose and lactide: their synthesis and characterization 1 Depu Chen ) , Baoquan Sun Department of Chemistry, Tsinghua UniÕersity, Beijing 100084, People’s Republic of China Accepted 17 September 1999 Abstract Ž . This paper reported the grafting copolymerization of L-lactide onto hydroxyethyl cellulose PLA-HEC or hydroxypropyl cellulose Ž . PLA-HPC . They were obtained from ring-opening copolymerization of L-lactide with HEC or HPC in different mole ratios at 1288C. Ž . 1 Sn Oct or LiCl was used as catalysts for the polymerization reaction. 400 MHz H NMR analysis of products indicated that both 2 Ž . Sn Oct and LiCl could catalyze the reactions. Both PLA-HEC and PLA-HPC were biodegradable polymers with a good bioabsorbabil- 2 ity, lack of toxicity, and were suitable for the use as tissue engineering materials. q 2000 Elsevier Science S.A. All rights reserved. Keywords: Copolymers of hydroxyalkyl cellulose and lactide; Ring-opening copolymerization 1. Introduction The application of renewable resources to synthesize biodegradable polymers with desired physico-chemical and biological properties has recently received increasing inter- wx ests 1 . Cellulose is the most abundant renewable biomass in the world. But cellulose has poor properties of biodegradability and bioabsorbability. Homo- or copoly- mers of lactide are well known to be the best biomaterials because of their biodegradability and bioabsorbility. Copolymers obtained from lactide and cellulose will com- bine the advantages of both, and may be used as tissue engineering materials. Tissue engineering is an interdisci- plinary field that applies the principles of engineering and the life science toward the development of biological substitutes that restore, or improve tissue function. Tissues or cells of organs are cultured on the matrices of biodegradable polymers to grow new tissues or organs with desired shapes and constructions, and then trans- planted back to the body for restoring, replacement of those tissues or organs damaged. After the formation of new tissues, the matrix polymers degrade gradually into the innoxious small molecular compounds, which are ab- wx sorbed by the body or excluded out of the body 2 . ) Corresponding author. Ž . E-mail address: chendp@sam.chem.tsinghua.edu.cn D. Chen . 1 Project supported by the National Natural Science Foundation of Ž . China 29776030 . Presently, there has been quite a few investigations dealing with the biodegradable polymers containing poly- lactide and polysaccharide blocks. Dainippon Ink and wx Chemicals 3 developed a method to manufacture trans- parent lactide-cellulose copolymer by grafting copoly- merization of lactide on cellulose acetate catalyzed by w Ž . x stannous 2-ethylhexanoate Sn Oct . Daicel Chemical In- 2 wx dustries in Japan 4 applied cellulose derivatives to react Ž . with lactide in N, N-dimethylacetylamide DMAc rLiClrEt N. A variety of catalytic systems has been 3 developed to catalyze ring-opening homo- or copolymer- wx ization of lactide: aluminum isopropoxide 5, Ž . wx tris 2,6-di-tert-butylphe-noxy yttrium 6 are all effective catalysts. In this paper, we reported the grafting copoly- Ž merization of L-lactide onto hydroxyethyl cellulose PLA- . Ž . Ž . HEC and hydroxypropyl cellulose PLA-HPC . Sn Oct 2 and LiCl were used as catalysts for these grafting copoly- merization reactions with different mole ratios at 1288C. Both PLA-HEC and PLA-HPC are biodegradable, lack toxicity, and are suitable for the use as tissue engineering materials. 2. Experimental 2.1. 1 H NMR Proton nuclear magnetic resonance spectra were recorded on Varian VXR-400 Spectrometer from the solu- tion of CDCl and DMSO-d . 3 6 0928-4931r00r$ - see front matter q 2000 Elsevier Science S.A. All rights reserved. Ž . PII: S0928-4931 00 00131-4