Biocompatible Hyaluronic Acid-Stabilized Copper Nanoparticles for the Selective Oxidation of Morin Dye by H₂O₂

In this study, we report the synthesis and characterization of biocompatible hyaluronic acid-stabilized copper nanoparticles (HA-CuNPs) and their catalytic evaluation in the oxidation of morin as a model compound. HA-CuNPs have been characterized by several state-of-the-art analytical techniques, such as FESEM, STEM, UV-Vis, DLS, zeta potential, FTIR and XRD analyses. The average particle size and surface zeta potential of HA-CuNPs were determined to be 35 nm and -28 mV, respectively. The catalytic activity of HA-CuNPs was investigated in the oxidative degradation of morin dye in the presence of H₂O₂. The kinetic data show that the oxidation process follows a pseudo-first-order reaction, and the rate constant is dependent on the concentrations of morin, H₂O₂, and HA-CuNPs. In addition, HA-CuNPs were employed for the selective oxidation of morin on four important synthetic dyes, i.e., Congo red, methylene blue, zinc-phthalocyanine, and quinizarin. The high selectivity indicates the possible use of HA-CuNPs as low-temperature bleach catalysts for the oxidation of stains such as tea, coffee, and red wine, which contain polyphenolic compounds like morin. Further, cytotoxicity studies demonstrated the low toxicity and high biocompatibility of HA-CuNPs to Caco-2 human colorectal adenocarcinoma cells, MCF-7 human breast cancer cells, and HUVEC normal human umbilical vein endothelial cells. Combining biocompatibility with high catalytic activity could boost the potential of this eco-friendly nanocatalyst in various applications, such as wastewater treatment, laundry, textile, and wood pulp bleaching.