Potentiometric detection of DNA hybridization using enzyme-induced metallization and a silver ion selective electrode.
Here, we report on a highly sensitive potentiometric detection of DNA hybridization. The new assay uses a low-volume solid-contact silver ion-selective electrode (Ag(+)-ISE) to monitor the depletion of silver ions induced by the biocatalytic reaction of the alkaline-phosphatase enzyme tag. The resultant potential change of the Ag(+)-ISE, thus, serves as the hybridization signal. Factors affecting the potentiometric hybridization response have been optimized to offer a detection limit of 50 fM (0.2 amol) DNA target. The new potentiometric assay was applied successfully to the monitoring of the 16S rRNA of E. coli pathogenic bacteria to achieve a low detection limit of 10 CFU in the 4 microL sample. Such potentiometric transduction of biocatalytically induced metallization processes holds great promise for monitoring various bioaffinity assays involving common enzyme tags.
Wu
Jie
J
Department of Nanoengineering, University of California San Diego, La Jolla, California 92093, USA.
Chumbimuni-Torres
Karin Y
KY
Galik
Michal
M
Thammakhet
Chongdee
C
Haake
David A
DA
Wang
Joseph
J
D000469:Alkaline Phosphatase / Q000737:chemistry / Q000378:metabolism*; D004247:DNA / Q000032:analysis*; D004566:Electrodes; D006046:Gold / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry; D009693:Nucleic Acid Hybridization; D011199:Potentiometry; D012834:Silver / Q000737:chemistry*; D013499:Surface Properties
D012834:Silver; D006046:Gold; D004247:DNA; D000469:Alkaline Phosphatase