Photodynamic Therapy overcoming Tumor Hypoxia by Self-oxygen generation Catalase Conjugated Metal-Organic-Framework Nanosystem

Abstract

Photodynamic Therapy (PDT) is a form of a phototherapy inducing cell death using light, oxygen and Photosensitizer (PS) which is generating ROS. These ROS interact with cellular components including lipids, amino acid and nucleic acids, and lead to the cell dysfunction. However, as a tumor grows, it rapidly outgrows its blood supply, leaving portions of the tumor where the oxygen concentration is significantly lower than in healthy tissues. For this reason, even effective photosensitizers cannot be working efficiently as much as expected. Therefore, if we overcome this hypoxia environment of tumor, photodynamic therapy can be more effective way forward. In our research, we conjugate the enzyme catalase (CAT) to surface of biocompatible nanocarrier MOF808. Catalase catalyzes the decomposition of hydrogen peroxide (H2O2) to water (H2O) and oxygen (O2). The generated oxygen can relieve the Hypoxia condition in tumor. Enriched oxygen further increases the PDT effect, enabling effective ROS generation. Also, immobilized enzyme is more stable than the free form of the enzyme enhancing the recyclability of enzymes and minimizing enzyme contamination.