荧光探针法研究壳聚糖水凝胶形成过程及其性能

基于芘(Py)单体荧光光谱结构对微观环境变化的敏感性，以及介质粘度及Py分子间距对Py激基络缔合物形成的影响，以戊二醛交联壳聚糖(CS)水凝胶体系为例研究了Py荧光探针法监测水凝胶形成过程及其溶胀性能的可行性。结果表明，Py荧光光谱精细结构的变化(以I~3/I~1为参量)或Py激基缔合物荧光强度与单体荧光强度之比(I~E/I~M)的变化与CS水凝胶的形成及溶胀程度有很好的对应关系。此外，CS凝胶网状结构中包埋的聚N-异丙基丙烯酰胺(PNIPAM)的构象变化也可由探针光谱变化反映出来。利用这种荧光探针方法有助于从分子水平上探知凝胶形成过程的微观本质。此外，这种方法也可作为光纤传导监测凝胶形成过程和溶胀的基础。

Study of the chitosan gel formation process and the gel properties using fluorescence probe

Because of the sensitivity of the fine structure of the fluorescence emission spectrum of the monomer of pyrene(Py) to its microenvironment and the dependence of the excimer formation on the visicosity of the medium and the distance between the probe molecules, pyrene was employed as a fluorescence probe to monitor the chitosan(CS) gel formation process and the gel swelling properties. It was shown that the changes in the fine structures (I3/I1) of its fluorescence spectrum and/or its excimer formation efficiency (IE/IM) was well related to the gelation process and the gel swelling degrees. The conformational change of the PNEPAM trapped in the CS gel could also be monitored by the probe technique. The present results may be taken as the basis for the design of an opticfibe method, which may be used to monitor gel formation and swelling processes.