Biomimetic CaCO3 microspheres as a promising delivery system for catalase: Immobilization, kinetic studies and potential perspectives in oxidative stress diseases

Oxidative stress is implicated in the pathophysiology of several illnesses. Catalase (CAT), an antioxidant enzyme, remains a prime target for oxidative stress related therapies. Unfortunately, the labile nature, difficulty in recovering and reusing, and insufficient delivery systems limit its use in therapy. This study used a simple biomineralization process for the synthesis of vaterite porous calcium carbonate (CaCO 3 ) microspheres (MS) for the development of cross-linked immobilized (CAT-MS). Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), particle size analysis , and zeta-potential measurements were used for CaCO 3 -MS characterization. CAT was immobilized efficiently with a high immobilization yield (99 %). The immobilized enzyme had a higher Km than free CAT with a 1.7 fold increase in Vmax and Kcat. CAT-MS displayed a longer half-life, efficient reusability, enhanced storage stability, and excellent stability against various denaturants compared to free CAT. Furthermore, CAT-MS demonstrated negligible cytotoxicity in the fibroblast cell line (BJ1), where CAT-MS recorded higher cell viability than free CAT, (p< 0.05) indicating exceptional biocompatibility . This study raises the potential of an eco-friendly approach that enforces wide and safe catalase application in intracellular therapy for treating oxidative stress-associated diseases.