Microgels of alginate dialdehyde with WGA lectin conjugate for curcumin encapsulation

Wheat germ agglutinin (WGA) is a plant-lectin that is potentially attractive to be used in the formulation of drug delivery systems. In this study, we report the synthesis and use of this lectin in a microgel formulation together with a modified alginate for drug delivery purposes. The alginate used in the formulation was obtained by oxidation of Na-alginate and contains reactive aldehyde groups (ADA). These aldehyde groups are essential and able to form a conjugate with lectin (ADAWGA) using a reductive amination protocol. ¹H NMR, DOSY, and ATR-FTIR were performed to characterize ADAWGA and confirm that the reaction is successful. Microgels based on ADAWGA were prepared by a micro emulsion technique utilizing calcium chloride as a crosslinking agent. For comparison, microgels with only the alginate and alginates in combination with ADA were also prepared. Microgels with average particle sizes ranging from 285 to 529 nm were obtained. The microgels were loaded with curcumin, a hydrophobic natural polyphenol, and the release pattern was investigated. The result of the release profiles from the curcumin-loaded microgels shown that the profile was fit the Higuchi model, whit the R² values range from 0.90 to 0.98. Cytotoxicity studies revealed that the microgels exhibit low toxicity toward the MCF-7 cells at low concentrations, making them suitable for drug delivery application.