Functional nucleic acid sensors

Functional DNA and RNA sensors, the nucleic acid enzyme (NAE) based sensors, are reviewed. Selection of a UO ² ion-specific RNA-cleaving DNAzyme is used to illustrate the principle of selection of DNAzymes. It is found that during selection for RNA-cleaving DNAzymes, if a fluorophore and a quencher is incorporated immediately adjacent to the cleavage site, the resulting NAEs are found as sensors after selection. An investigation of Pb ²⁺-induced disassembly of AuNP aggregates show that the DNAzyme is inactive in head-to-tail aligned aggregates and active in tail-to-tail aligned aggregates. AuNPs are employed as quenchers for designing structure-switching aptamer sensors for protein detection. The performance of the aptamer-based system is comparable to traditional all antibody-based Enzyme-linked immunosorbent assays (ELISA) detections, and a detection limit of 25 ρg/mL is reported.