离子液体再生纤维素水凝胶的形成机理及其在凝胶电泳中的应用

FORMATION MECHANISM OF IONIC LIQUID-RECONSTITUTED CELLULOSE HYDROGELS AND THEIR APPLICATION IN GEL ELECTROPHORESIS

以离子液体为溶剂,将天然纤维素溶解后,以水作为溶剂浴可再生出一种新型纤维素水凝胶.元素分析和红外光谱测试结果表明得到的纤维素水凝胶中只含有纤维素和水.纤维素水凝胶具有很高的透明度,2mm厚的水凝胶在650 nm处的透光率可以达到80%.应力应变试验结果表明纤维素水凝胶具有可接受的力学强度,能满足一般的应用要求.凝胶电泳的初步实验结果表明纤维素水凝胶可用做凝胶电泳支持物,可成功分离染料甚至蛋白质等目标分子.讨论了再生纤维素水凝胶的形成机理.多种溶剂均可制备相应的纤维素凝胶.研究发现,溶剂的性质将决定相应的纤维素凝胶是否可以形成.如果溶剂分子能够与离子液体混溶,而且溶剂分子中含有活泼氢,则该溶剂将可能在溶剂/纤维素体系中通过氢键构筑出三维网络结构,从而有助于该溶剂纤维素凝胶的形成.

A novel cellulose hydrogel was prepared by regenerating cellulose from its ionic liquid（IL） 1-allyl-3-methylimidazolium chloride（AMIMCl） solution.The results from elemental analysis and FTIR spectroscopy indicate that the cellulose hydrogel was composed of only natural cellulose and water.Therefore,the hydrogel is non-toxic and can be a promising material in bioengineering.UV-Vis spectra demonstrate that the cellulose hydrogel has a good transparency,especially in the larger wavelength region.For instance,a 2 mm-thick hydrogel can reach 80% transmittance at 650 nm.The results of compression test show that the cellulose hydrogel has an acceptable mechanical property.All the cellulose gels（the cellulose content differs from 1% to 3%） can bear a strain more than 50% upon compression without failure,which allows normal handle in applications.Numerous nano-pores with size of 20~60 nm can be observed from the SEM images of the cellulose hydrogel,indicating that the hydrogel may be utilized in separating nano-sized objects.In this study,we find that cellulose hydrogels reconstituted from its IL solution can be used as the diffusion matrix in gel electrophoresis（GE）,and our preliminary results show that dyes and even proteins can be successfully separated.As a green material,the cellulose gel is expected to overcome the disadvantages of the polyacrylamide gel,which is traditionally used in GE.The mechanism of the formation of cellulose hydrogel from its IL solution was also discussed.It is observed that several kinds of solvents can prepare cellulose hydrogel from its IL solution.The experiment results suggest that the properties of a certain solvent determine whether cellulose gel can be prepared in the solvent bath.If the solvent is miscible with the IL,and the molecule of the solvent has one or more active H atom,then the solvent may form a H-bonding network with the IL solution,which is helpful for the formation of the cellulose gel.