Preparation, characterization, and cellular uptake of resveratrol-loaded trimethyl chitosan nanoparticles.

The aim of the study was to encapsulate resveratrol (RV) in trimethyl chitosan (TMC) nanoparticles cross-linked with tripolyphosphate (TPP) and/or alginate to achieve controlled release and improved cellular uptake. TMC (degree of quaternization of 78%) was prepared by reacting purified chitosan with iodomethane. Three types of RV-loaded TMC nanoparticles were prepared: TMC-TPP (TP-NPs), TMC-alginate (TA-NPs), and TMC-alginate-TPP (TAP-NPs). TA-NPs and TAP-NPs showed lower particle size and encapsulation efficiency (EE), better distribution, and more sustained release than TP-NPs due to the high molecular weight and viscous property of alginate. Caco-2 cellular uptake of RV was improved by TMC nanoencapsulation, and TP-NPs showed the highest uptake due to its significantly higher EE. Compared with TAP-NPs, TA-NPs with higher positive surface charge showed higher cellular uptake. Moreover, Caco-2 cell growth-inhibiting activity of RV was significantly increased by TMC nanoencapsulation and TP-NPs showed the significantly highest activity with a good agreement with the permeability results.