孔径可调控的多孔纤维素的构建及功能化改性研究

Cellulose is a kind of abundant natural resources with extensive application prospect, but cellulose surface is difficultly modified due to the high crystallinity. In this project, porous celluloses (PCs) are prepared in the processing of dissolving cellulose in ionic liquids (ILs), freezing the solution to obtain the crystallization of ILs for preparing porous structures, which were controlled by adjusting the nucleation, crystal growth and crystal size of ILs. PCs will exhibit a large specific surface area, polyhydroxy groups and low crystallinity, which can make the functional modification of PCs simple and feasible, and endow novel functions without destroying pore structure. And PC modifications are expected to achieve adsorption and template functions. The immobilization of urease on dialdehyde PC can improve the adsorption and selectivity for urea in body. PCs are used as porous templates to prepare porous carbon materials. In the reduction process of graphene oxide (carbon nanotube oxide or carbon black oxide), the ether bond is formed between PCs and carbon materials. When the composites are carbonized as the electrodes with removing cellulose components, the diffusion paths with different textures are formed in porous carbon materials to detect biomolecules as the biosensors. To improve the conductivity of porous carbon materials, three oxidized carbon materials can be grafted on PCs together. The project will provide a scientific basis for the preparation of controllable porous materials from natural polysaccharides, the modifications and the application on the medical field of uremia drugs and biosensors.

天然纤维素资源丰富、应用前景广泛，但高结晶度和致密表面造成其改性困难，限制了其实际应用。本项目采用离子液溶解纤维素、冷却结晶离子液及结晶替代法制备孔径可调控，具有大比表面、多羟基和低结晶度等特点的多孔纤维素，有利于其表面功能改性。采用两种方法对其功能改性并进行应用研究：一是双醛化-固定化酶改性，研究孔径对双醛取代度和脲酶负载量的影响，实现多孔纤维素对体液中尿素的高选择性吸附；二是接枝碳材料改性，以多孔纤维素为模板，通过氧化-还原反应分别将石墨烯、碳纳米管或纳米碳黑等接枝到相应孔径的多孔纤维素表面，形成三维多孔结构。为提高导电性能，可将上述三种碳材料复合接枝到多孔纤维素上，还可在氮气或氩气保护下将多孔纤维素接枝碳材料制成炭化型多孔碳材料。将上述多孔纤维素接枝碳材料分别制成电极，用于生物分子检测研究。本项目用多孔纤维素孔径调控和功能改性为其在尿毒症药物和生物传感器等医疗领域的应用提供科学依据。

纤维素是地球上来源最广、含量最丰富的天然可再生资源，生物相容性良好、可降解、安全环保且价格低廉。在如今不可再生资源日益短缺的现状和可持续发展的迫切要求下，纤维素的功能化和应用成为各界的研究热点。但其高结晶度和致密表面造成其改性困难，限制了其实际应用。本项目采用离子液溶解纤维素、冷却结晶离子液及结晶替代法制备孔径可调控、具有大比表面、多羟基和低结晶度等特点的多孔纤维素，有利于其表面功能改性。采用两种方法对其功能改性并进行应用研究：一是双醛化-固定化酶改性，研究孔径对双醛取代度和脲酶负载量的影响，实现多孔纤维素对体液中尿素的高选择性吸附；二是接枝碳材料改性，以多孔纤维素为模板，通过氧化-还原反应分别将石墨烯、碳纳米管或纳米碳黑等接枝到相应孔径的多孔纤维素表面，形成三维多孔结构。为提高导电性能，可将上述三种碳材料复合接枝到多孔纤维素上，还可在氮气或氩气保护下将多孔纤维素接枝碳材料制成炭化型多孔碳材料。将上述多孔纤维素接枝碳材料分别制成电极，用于生物分子检测研究。发表SCI论文6篇，培养硕士研究生6人。本项目用多孔纤维素孔径调控和功能改性为其在尿毒症药物和生物传感器等医疗领域的应用提供科学依据。制备的气凝胶改性新材料在去除有机染料和抗生素废水等方面也表现优异。这些改性方法为纤维素的进一步研究和开发拓宽了研究思路和方向，这些研究成果的发现也为此提供了强有力的支持。