Dual-mode regulatory cross-linked chitosan nanocapsules for pH-responsive and controllable sustained release in...

Stimuli-responsive microcapsules enable controlled release of core materials in response to environmental triggers, offering greater application potential than conventional systems, particularly in smart textiles and drug delivery. However, challenges persist in enhancing encapsulation efficiency, stability, and achieving sustained, controllable release under specific environmental conditions. In this study, dual cross-linked chitosan nanocapsules (DC) encapsulating Lavender essential oils were synthesized through a combination of electrostatic interactions between chitosan and sodium tripolyphosphate and Schiff base reactions between chitosan and glutaraldehyde. The resulting nanocapsules, approximately 50 nm in size, exhibited an encapsulation efficiency of 93.18 % and a loading capacity of 14.54 %. They demonstrated sustained release, retaining 77.11 % of their content after 36 days at room temperature, as well as notable thermal stability. Additionally, under alkaline conditions (pH = 10), the nanocapsules showed enhanced release rates, confirming their pH-responsive behavior. When loaded onto cotton fabrics via electrostatic adsorption, the functionalized fabrics exhibited slow-release properties. These findings highlight the potential of dual cross-linked chitosan nanocapsules as multifunctional and innovative delivery systems for diverse applications.