A robust emulsion gel based on κ-carrageenan and dialdehyde starch for stimuli-responsive of hydrophobic bioactive agents

Abstract

In this study, a green and sustainable emulsion gel was developed using kappa-carrageenan (kappa C) and dialdehyde starch (DS) for the stimuli-responsive delivery of the hydrophobic bioactive agent, curcumin (CU). Initially, CU was encapsulated within kappa C-based emulsion gels, with kappa C serving as a natural stabilizing and gel-forming agent. Subsequently, DS, containing reactive aldehyde groups (AGs), was introduced to chemically cross-link with the hydroxyl groups of kappa C via a hemiacetal reaction, resulting in a porous and stable emulsion gel structure (kappa CDS@CU). The presence of DS enhanced the structural integrity of the gels and facilitated safe passage through simulated intestinal conditions. The engineered kappa CDS@CU emulsion gels demonstrated improved textural properties, high encapsulation efficiency, and sustained release behavior. Moreover, cytotoxicity assessments confirmed their biocompatibility, supporting their suitability for oral delivery. This rationally designed, biopolymer-based emulsion gel offers a promising platform for the effective encapsulation and targeted delivery of hydrophobic bioactive compounds.