Application of thermal alkaline hydrolysis technology to improve the loading and in-vitro release of gallic acid in UiO-66

The purpose of this study was to treat UiO-66 (University of Oslo 66) under suitable thermal alkaline hydrolysis condition to realize the loading of gallic acid. UiO-66-SH (UiO-66-separated-heating) was obtained by separated heating UiO-66 and 0.2 M KOH aqueous solution to 120 ℃ before mixing for 3 h. The material was in an amorphous state, maintained the octahedron structure and size of UiO-66. UiO-66-SH has better porosity and specific surface area than UiO-66, and had good thermal stability until heated to 1000 ℃. Furthermore, UiO-66-SH had very little influence of the cellular activity of human normal heptical cell line, demonstrating its good biocompatibility. The prepared UiO-66-SH could successfully adsorb gallic acid and control the release of gallic acid in simulated gastric fluid (∼58% vs.  ∼ 88% of free gallic acid). This study will be conducive to preparation of appropriate carrier used to load with polyphenolic compounds such as gallic acid.