In Vitro Selection of New DNAzymes as Metal Biosensors

Abstract

In vitro selection of metal-specific DNAzymes has been shown to be a powerful method to obtain biosensors for metal ion detection. With 14 independent in vitro selection experiments using each of the trivalent lanthanide as the metal cofactor, five DNAzymes with distinct activity patterns cross the lanthanide series were identified and characterized. In addition, these DNAzyme beacon sensors were developed by using fluorophore/quencher modified pairs. Each of these DNAzymes showed low nM lanthanide detection limit with minimal interference from other metals. A sensor array was prepared to achieve pattern-recognition-based detection using linear discriminant analysis (LDA), where most of the 14 lanthanides can be well separated. In addition, a selection using a phosphorothioate modified DNA library was carried out and a new DNAzyme with high sensitivity and specificity for Cd2+ was obtained.