聚乙二醇生物相容性与结合水关系的单分子力谱研究  

Revealing the Relationship between the Biocompatibility and the Bound Water of Poly(ethylene glycol)by Single-molecule Force Spectroscopy

作　　者：许俊[1] 曹楠普 肖尧鑫 罗仲龙 鲍雨 崔树勋[1] Jun Xu;Nan-pu Cao;Yao-xin Xiao;Zhong-long Luo;Yu Bao;Shu-xun Cui(Key Laboratory of Advanced Technologies of Materials,Ministry of Education,Southwest Jiaotong University,Chengdu 610031)

机构地区：[1]材料先进技术教育部重点实验室,西南交通大学,成都610031

出　　处：《高分子学报》2020年第7期754-761,I0004,共9页Acta Polymerica Sinica

基　　金：国家自然科学基金青年基金(基金号21604013);中央高校基本科研业务费专项资金(项目号2682018CX08)资助项目.

摘　　要：聚乙二醇(PEG)优良的生物相容性使得其在生物材料领域的应用十分广泛,但关于其具有良好生物相容性的分子机理依然不清楚.本文利用单分子力谱技术研究了PEG生物相容性与其结合水之间的关系.PEG在非极性有机溶剂-壬烷及磷酸盐缓冲液(PBS)中的力-距离(F-E)曲线之间存在显著的差异.通过实验分析及单分子理论模型验证发现这一差异主要是由PEG结合水重排所导致的.对壬烷及PBS中的F-E曲线间的面积差进行积分得到PEG结合水重排所额外消耗的能量(Ew)为~1.59 kBT/unit(3.93 kJ/mol).通过对比发现,此Ew与生物大分子的Ew最为接近.我们推测这一与生物大分子相近的Ew值保证了PEG在生物体内既不会引起严重的能量波动也不会影响其他分子的行为,这可能是PEG具有优良生物相容性的一个重要因素.Poly(ethylene glycol)(PEG)has become the“superstar”in the field of biological materials due to its excellent biocompatibility.However,the molecular mechanism underlying its biocompatibility is still unclear.In this work,we have investigated the relationship between the biocompatibility and the bound water of PEG by single-molecule force spectroscopy(SMFS).To discern the effect of bound water on PEG in an aqueous solution,the single-chain inherent elasticity of PEG should be determined first as a reference.The inherent elasticity of PEG is obtained in a small-sized nonpolar organic solvent,nonane,which is confirmed by the quantum mechanical calculations-based freely rotating chain model(QM-FRC model).Then,SMFS experiments have been performed in phosphate-buffered saline(PBS)to study the effect of bound water on PEG.The shoulder plateau in the force-extension(F-E)curve of PEG obtained in PBS should be caused by the rearrangement of the bound water(water bridge)during the PEG elongation.This assumption has been confirmed by the two states QM-FRC model(TSQM-FRC model),which takes into account the effect of the water bridge.This bound water rearrangement will consume additional energy(Ew)besides that for the inherent elasticity of the chain.This Ew is calculated to be^1.59 kBT/unit(3.93 kJ/mol)by integrating the area between the F-E curves of PEG obtained in PBS and nonane,closed to those of biomacromolecules.Inspired by the relationship between the low Ew and the behaviors of biomacromolecules,we have speculated the relationship between the biocompatibility and the bound water of PEG:(1)Like those of biomacromolecules,this Ew makes sure that the conformational transition of PEG in blood or cell will not consume(or produce)too much energy.Thus,the energy disturbance caused by PEG can be borne by the organism.(2)An appropriate Ew can prevent the aggregation of biomacromolecules and PEG.Biomacromolecules can self-assemble into the high-level structure after partial dehydration.If PEG has no bound water(Ew=0),PEG may

关 键 词：聚乙二醇 生物相容性 结合水 单分子力谱 

分 类 号：R318.08[医药卫生—生物医学工程]