DNAzymes as key components of biosensing systems for the detection of biological targets

DNAzymes are synthetic functional nucleic acids that have found widespread use in biosensing applications both for molecular recognition and signal generation. Two classes of DNAzymes have proved particularly effective for use in proof-of-concept biosensing systems, namely RNA-cleaving DNAzymes (RCDs) and peroxidase mimicking DNAzymes (PMDs). RCDs catalyze the site-specific cleavage reaction of an RNA dinucleotide junction, generating two cleavage fragments. PMDs are capable of catalyzing peroxidation reactions of chromophores, thereby generating a measurable signal. Herein, we review the use of these DNAzymes in biomedical assays and diagnostics, and show that this emerging field should have great promise for biosensor development over the next few decades.