Preparation and properties of thermosensitive molecularly imprinted polymer based on konjac glucomannan and its controlled recognition and delivery of 5-fluorouracil

Biocompatible thermosensitive molecularly imprinted polymers (MIPs) based on konjac glucomannan was prepared by graft copolymerization of N -isopropyl acrylamide , a thermosensitive monomer , with konjac glucomannan, a natural polysaccharide . The products were characterized by various means. The MIPs possessed switchable thermal regulation on the recognition and delivery of 5-fluorouracil (5-Fu), an anticancer drug . The results of adsorption experiments showed that the MIPs had excellent adsorption capacity at a temperature below the lower critical solution temperature, and the MIPs could specifically recognize and adsorb 5-Fu with good selectivity, repeatability, and stability. The adsorption isotherms of MIPs were fitted by six isothermal models and the dual-site Langmuir- Freundlich model presented the best fit. In addition, the in vitro release properties of 5-Fu from the thermosensitive MIPs were evaluated in phosphate buffer solution and the cumulative release of 5-Fu at 25 °C was higher than that at 38 °C. The release curves were fitted by zero-order, first-order, and Higuchi kinetic equations, respectively, and the results showed that the release of 5-Fu complied with the Fick 's law. Compared with non-molecularly imprinted polymers, the MIPs could release 5-Fu continuously for a certain period with a good controlled release effect, indicating that they possess great prospects as drug delivery materials.