Simultaneous effects of synthesis conditions on calcium/chitosan/deep eutectic solvent-functionalized graphene oxide...

In this study, the carriers fabricated from ethylene glycol-derived deep eutectic-functionalized graphene oxide (GO) (DES-functionalized GO (GO-E)), chitosan (CTS) polymer, and calcium (Ca) were prepared by hydrothermal and freeze-drying methods, in which various factors, including GO-E:CTS concentration ratio, hydrothermal time, and hydrothermal temperature, were evaluated to simultaneously affect the loading capacity of l-ascorbic acid (LAA) through response surface methodology using the Box - Behnken model. The results showed that at the actual values with GO-E:CTS concentration ratio of 2.40, hydrothermal time of 164 min, and hydrothermal temperature of 140 °C, the highest LAA loading capacity reached 406.678 mg.g^-1. The optimized LAA-loaded Ca/CTS/GO-E carriers were then integrated into products, including films, fabrics, tablets, and encapsules, to identify characteristics, properties, and LAA release efficiency under different pH environments, along with the individual carriers. Finally, the bioactivities of these carriers and products, encompassing antibacterial, antioxidant, anti-inflammatory, hemolytic, and cytotoxicity, were also examined. As a result, the LAA-loaded Ca/CTS/GO-E carriers exhibited higher LAA release in pH 7.4 than that in pH 5.4, while the highest release value was attributed to the tablet products. The carriers and products also involved inhibitory effects on bacterial growth and DNA cleavage on both Gram-negative and Gram-positive strains. Meanwhile, the antioxidant activity via DPPH and ABTS assays, as well as the resistance to thermal protein denaturation of the LAA-loaded Ca/CTS/GO-E carriers. Furthermore, hemolytic activity also expressed relatively low results after loading LAA into the matrix and integrating it into the products. These results demonstrate the wide application potential of the Ca/CTS/GO-E carriers as effective DDSs and biomedical treatments.