Undenatured type II collagen nanofibrils with sodium alginate coating: Structural characterization, physicochemical properties and capability to load curcumin

Abstract

In this study, the structural design and physicochemical property enhancement of undenatured type II collagen (CII) nanofibrils with sodium alginate (SA) coating induced by calcium ions (Ca2+) were investigated. The research aimed to elucidate the impact of Ca2+ concentration on the morphology, thermal stability, and digestive resistance, as well as to assess the potential of CII/SA nanofibrils as a delivery system for curcumin (Cur). A series of Ca2+ concentrations (1–9 mM) were methodically applied to optimize the condition that maintains the triple-helical structure of CII, thereby enhancing its functional properties. It was found that the Ca2+ level up to 5 mM effectively preserved the structural integrity and improved thermal stability of CII, with the added benefit of ensuring the substantial delivery of active fragment to small intestine (70.7 %), which was 3.43 times greater than that of uncoated CII. Moreover, incorporating Cur into the CII/SA nanofibrils resulted in a 300 times increase in Cur solubility and showcased the superior dispersion stability, antioxidant activity, and sustained release profile during simulated digestion. These findings underscored the dual functionality of the CII/SA system as both a stabilizing agent for CII nanofibrils and an efficient carrier for Cur delivery.