A high-amylose maize starch hydrogel mask for stabilized encapsulation of thyme essential oil with Higuchi-controlled release.

This study developed a facial mask matrix based on a high-amylose maize starch (HAMS) hydrogel for the encapsulation and sustained release of thyme essential oil (TEO), aiming to overcome the volatility and instability of its active constituent, thymol. A stable three-dimensional network was constructed via physical gelation and ionic cross-linking. The hydrogel exhibited excellent hydrophilicity and suitable moisturizing performance (water vapor transmission rate = 1100 g·m-2·24 h-1). In PBS (pH 7.4), the release of thymol followed the Higuchi model (R2 = 0.97), indicating diffusion-controlled kinetics, with a cumulative release of 30% over 30 h and no initial burst. The TEO-loaded hydrogel (2% TEO) showed potent, dose-dependent antibacterial activity against Staphylococcus aureus (inhibition zone = 22 mm) and Escherichia coli (20 mm), achieving >95% bacterial reduction. Significant antioxidant capacity was confirmed by DPPH and ABTS+ assays. Biocompatibility assessments verified outstanding hemocompatibility (hemolysis rate < 5%) and low cytotoxicity (cell viability > 85%). This study demonstrates the feasibility of using HAMS hydrogels for the stabilized delivery of bioactive essential oils in advanced skincare applications.