ZIF-8/cellulose microspheres prepared in situ to control release of 5-fluorouracil
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 and π-π stacking.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.