Hydrogen peroxide-triggered small molecule theranostics for cancer therapy: A review

Theranostics (combination of diagnosis and therapy) have received great research interest in the field of cancer as they allow specific delivery of drug to cancer cells with simultaneous diagnose of pre-and post-treatment drug assessment. These systems provide transition from conventional medicine to personalized medicine. Small molecule theranostics are more advantageous owing to their unique properties such as small size and simple design, biocompatibility, and unidirectionality. By exploiting various cancer cellular constituents (ROS, Enzymes, pH etc.) overexpressed in cancer cells, these conjugates are selectively activated in cells to release active drug for tumor inhibition and imaging moiety for diagnosis without causing significant toxicity to normal cells. This review highlights hydrogen peroxide (H2O2)-responsive small molecules conjugates, their activation mechanisms and applications in cancer therapy.