琼脂糖基两性离子聚合物合成及其反聚电解质行为研究

Synthesis of Agarose-Based Zwitterionic Polymer and Its Anti-Polyelectrolyte Behavior

分子结构中含有甜菜碱基团的两性离子聚合物,由于独特的反聚电解质性质使其在药物释放、抗蛋白吸附、抗血栓材料等领域具有潜在的应用前景.但传统两性离子聚合物的可降解性较差,致使其在生物医学领域中的应用受到一定限制.本文以具有良好生物相容性及生物可降解性的琼脂糖为基本原料,开发了一种琼脂糖和3-[N,N-二甲基-[2-(2-甲基丙-2-烯酰氧基)乙基]铵]丙烷-1-磺酸内盐(SBMA)的接枝共聚物(agarose-g-PSBMA).首先,通过琼脂糖与溴-异丁酰溴(BIBB)之间的酰胺化反应合成引发剂agarose-Br,探索了BIBB用量、反应时间等参数对agarose-Br取代度的调控作用,结果发现随反应物中BIBB过量倍数的增加,agarose-Br的取代度(DS)逐渐增大.在此基础上,以agarose-Br为引发剂,通过ATRP反应,实现了SBMA在琼脂糖主链上的接枝聚合.通过调节SBMA与agarose-Br的投料比例,合成了一系列具有不同取代度及支链长度的agarose-g-PSBMA,且实验结果表明支链的聚合度与投料理论值基本保持一致,相对分子质量分布较窄(1.03<PDI<1.30),接枝聚合的可控性强.以[η]为目标参数,详细并系统地研究了agarose-g-PSBMA在不同NaCl浓度溶液中的反聚电解质行为,发现随NaCl溶液浓度的增加其[η]也增大,且agarose-g-PSBMA的[η]符合Huggins-Houwink方程的规律,具有明显的反聚电解质行为.研究结果将为拓宽多糖及两性离子类聚合物结构设计及应用提供新的思路.

Betaine-based polymer is one of the typical zwitterionic polymers,and its unique anti-polyelectrolyte properties are shown to be potentially applicable in the areas of drug release,anti-protein adsorption,antithrombotic materials,and others.However,the traditional zwitterionic polymer has poor degradability,which limits its application in the biomedical field.In this study,an agarose-graft-poly(3-dimethyl(methacryloyloxyethyl)ammonium propanesulfonate)(agarose-g-PDMAPS)(agarose-g-PSBMA)copolymer was synthesized based on agarose with good biocompatibility and biodegradability.First,the macroinitiator of agaorose-Br was synthesized through the reaction of agarose and bromoisobutyryl bromide(BIBB).Substitution degree(DS)of the agarose-Br was adjusted by the feeding ratio of agarose and BIBB.Results suggested that the DS gradually increases with enhanced BIBB excess multiples.A series of copolymers were then synthesized by ATRP using agarose-Br as an initiator and SBMA as a monomer,varying graft degrees and graft lengths.Results suggested that the molecular weight of agarose-g-PSBMA is consistent with the theoretical values of the feed and the molecular weight distribution is narrow(1.03<PDI<1.30),indicating that the controllability of this graft polymerization is very high.Using intrinsic viscosity[η]as the target parameter,the[η]of agarose-g-PSBMA in NaCl solutions with different concentrations was investigated to evaluate its“anti-polyelectrolyte effect”.Results found that[η]increases along with the concentration of NaCl solution,and[η]of agarose-g-PSBMA conforms to the law of the Huggins-Houwink equation,suggesting that the agarose-g-PSBMA has obvious anti-polyelectrolyte behavior.These results should provide new ideas for broadening the structural design of polysaccharides and zwitterionic polymers and their applications.