Target-responsive DNAzyme probes for luminescence detection and imaging of DNA-modifying enzymes

DNA-modifying enzymes can specifically identify and repair the DNA damages caused by intrinsic/extrinsic factors, and they play crucial regulation roles in various cellular activities. Deregulated DNA-modifying enzymes may result in abnormal gene functions and consequently cause developmental disorders, senile dementia, and carcinogenesis progression. Therefore, the effective monitoring of DNA-modifying enzymes is critical to fundamental studies, clinical diagnostics, and cancer therapeutics. DNAzymes possess distinct advantages of good biocompatibility, low cost, specific binding, stable catalysis activity, and flexible programmability, making them popular as recognition elements and signal amplifiers for biosensing and bioimaging applications. In this review, we summarize recent progress in target-responsive DNAzyme probes for luminescence (fluorescence and chemiluminescence) detection and imaging of DNA-modifying enzymes (i.e., glycosylase, telomerase, polynucleotide kinase, methyltransferase/demethylase, and alkaline phosphatase) in the past decade. We summarize their strategies and applications in biosensing/bioimaging, and highlight the emerging challenges and directions in this field.