University of Science and Technology of China  South China University of Technology 中文|English

Biodegradable Materials

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Biodegradable materials are studied broadly for biomedical and pharmaceutical applications. Among them, the biodegradable polymers have been extensively employed as such biomaterials that must be biocompatible, processable, and capable of controlling stability in physiologic conditions. Polyphosphoester (PPE) is a class of biodegradable polymers with repeated phosphoester linkage in the backbone, where phosphorus is pentavalent and thereby allows binding bioactive molecules and being extensively tailored to modify the polymer properties physically and chemically. The favorable biocompatibility, biodegradability, and relatively controllable hydrophilicity of PPE through pendent modifications have demonstrated its potential in biomedical applications for nano-drug pharmaceutics, gene delivery, tissue engineering, etc.

1. We pioneered the use of aluminum isopropoxide as a catalyst to control the synthesis of polyphosphate, obtained the homo-polyphosphoester and block polymers. The main traditional synthetic strategies of polyphosphoester are polycondensation, addition polymerization, etc. However, it is difficult to regulate the polymerization reaction of polyphosphoester by these methods, including the molecular weight and structure of the components, which limits its application in the field of biomaterials. To our knowledge, our laboratory was the first to use aluminum isopropoxide as a catalyst to control the synthesis of polyphosphoester and obtain the homo-polyphosphoester and block polymers. The kinetics studies showed the reaction was a first-order kinetic process and it was a living reaction. Moreover, using aluminum isopropoxide as a catalyst, polyphosphoester block copolymer could be synthesized by a two-step continuous feeding method.

2. We developed a new catalytic synthesis system for polyphosphoesters with stannous octoate. The polymer structure and the reaction could be controlled by adjusting the reaction conditions. According to these polymerization approaches, the linear, brush-like, star, centipede-like polyphosphate amphiphilic polymers were synthesized with different functionalized phosphate monomers. In addition, nano-carriers with different morphology, such as vesicles, micelles, nanogels were obtained with assembly of the polyphosphoester-based amphiphilic polymers, and achieved the function of tumor targeting.