Nucleic acid-based biosensors are typically used to detect DNA or RNA fragments of genetic importance.
However, nucleic acids can also serve as binding partners for other molecules, including metal ions. This binding occurs
through electrostatic interactions between metal cations and negatively charged DNA strands and through the specific
binding of metal cations by donor atoms from the phosphate groups and nucleobases. Additionally, the ability of nucleic
acids to form secondary structures is of particular importance, as the formation of secondary structures can modify the interactions
with metal ions through shape-recognition effects. This article reviews electrochemical DNA sensors used for
metal ion quantification. These devices are divided into three categories: sensors with receptor layers composed of double-
stranded DNA (dsDNA), single-stranded DNA (ssDNA) or random-sequence oligonucleotides; sensors based on oligonucleotide
sequences that show high selectivity toward particular metal ions; and sensors that employ DNAzymes with
metal ion cofactors.
Keywords: DNA sensor, DNAzyme, electrochemical sensor, hybridization, metal ion determination, modified electrode.
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