原位制备ZIF-8/纤维素微球及其控制释放5-氟尿嘧啶的研究

ZIF-8/cellulose microspheres prepared in situ to control release of 5-fluorouracil

在纤维素微球(CM)上设计了沸石型咪唑骨架材料8/纤维素复合微球(ZIF-8@CM)作为5-氟尿嘧啶(5-FU)的载体并对5-FU进行控制释放。以CM、硝酸锌和2-甲基咪唑为原料,采用原位法制备了ZIF-8@CM。通过氢键、静电相互作用和π-π堆积作用将5-FU加载到ZIF-8@CM上。利用扫描电子显微术、能量色散X射线分析法、傅里叶变换红外光谱法、X射线衍射、X射线光电子能谱法和热重分析对样品进行表征,结果表明成功制备了ZIF-8@CM,并在ZIF-8@CM上成功加载了5-FU。ZIF-8@CM对5-FU的负载量可达74.10 mg·g^(-1),远高于CM(2.84 mg·g^(-1))。此外,ZIF-8@CM-5-FU可在pH=5.0的磷酸缓冲溶液(PBS)环境下持续释放5-FU 600 min,释放量达到63.4%,但在pH=7.4的PBS环境下仅释放37.6%。5-FU的释放遵循一级动力学和Fickian扩散机制。在细胞实验中已证实ZIF-8@CM具有良好的生物相容性和极低的细胞毒性,是5-FU安全释放的合适载体。本研究为设计一种5-FU的新型载体提供了思路。

Zeolitic imidazole framework 8/cellulose composite microsphere(ZIF-8@CM)was designed on the cellulose microsphere(CM)as the carrier of 5-fluorouracil(5-FU)to control the release of 5-FU.ZIF-8@CM was prepared by an in-situ method from CM,zinc nitrate and 2-methylimidazole.5-FU was loaded on ZIF-8@CM by hydrogen bonding,electrostatic interaction andπ-πstacking.The samples were characterized by scanning electron microscopy,energy-dispersion X-ray analysis,Fourier transform infrared spectroscopy,X-ray diffraction,X-ray photoelectron spectroscopy and thermogravimetric analysis.The results show that ZIF-8@CM is successfully prepared and 5-FU is loaded on ZIF-8@CM.The loading capacity of 5-FU can reach 74.10 mg·g^(-1),much higher than that of CM(2.84 mg·g^(-1)).In addition,ZIF-8@CM-5-FU can release 63.4%of 5-FU over 600 min in phosphoric acid buffer solution(PBS)at pH=5.0,but only 37.6%in PBS at pH=7.4.The release of 5-FU follows first-order kinetics and Fickian diffusion mechanism.Cell experiments prove that ZIF-8@CM have good biocompatibility and very low cytotoxicity,and ZIF-8@CM-5-FU is a suitable vector for safe release of 5-FU.This study provides an idea for designing a new type of 5-FU carrier.