PEGylated chitosan decorated UiO-66 nanoscale metal–organic frameworks as promising carriers for drug delivery

Nanoscale metal organic frameworks (NMOFs) have become excellent drug carriers for the treatment of cancer or other diseases, due to the advantages of large surface area, high drug loading, tunable structure and easy functionalization, with potential application in the field of drug delivery. In this paper, UiO-66 NMOF was synthesized using terephthalic acid as organic ligand and zirconium chloride as metal salt, and then biocompatible chitosan (CS) and PEGylated chitosan (CS-g-mPEG)-decorated NMOFs as drug carriers were constructed by surface modification, using 5-FU as the drug model. The structures, size and morphology were characterized by IR, XRD, DLS, SEM and TEM respectively. The results showed that when the concentration was 0.0872 M, the molar ratio was 1:1 and the acetic acid amount was 2.9 mL, the average particle size of NMOFs was 145.60 nm and 171.73 nm, respectively. The drug loading capacity and encapsulation rate could reach 15.7% and 52.8%. The in vitro controlled drug release results indicated that the release rate accelerated with increasing temperature and decreasing initial amount, greatly reduced under acidic conditions, and the coating of CS and CS-g-mPEG on the surface of UiO-66 had the effect of controlling drug release, further improved the bioavailability of 5-FU. The decorated UiO-66 NMOFs show excellent biocompatibility as nanodrug carriers and can avoid rapid degradation under gastric acid, which are more suitable for oral drug delivery.