Hexavalent Chromium as an Electrocatalyst in DNA Sensing.
Hamid R Lotfi Zadeh ZhadRebecca Y LaiPublished in: Analytical chemistry (2017)
We report for the first time the use of hexavalent chromium (Cr(VI)) as an electrocatalyst in electrochemical DNA sensing. For both stem-loop probe and linear probe electrochemical DNA sensors, the increase in probe rigidity upon target hybridization alters the accessibility of Cr(VI) to the methylene blue label on the surface-immobilized DNA probes. This change results in an enhancement in the electrocatalytic current when the sensors are interrogated using cyclic voltammetry at a slow scan rate. The incorporation of this electrocatalyst does not affect the normal "signal-off" sensing behavior observed in alternating current voltammetry; instead it enables simultaneous "signal-on" and "signal-off" detection of the target, while maintaining noted attributes of this class of folding- and dynamics-based sensors such as reusability and high selectivity. It is also capable of improving the limit of detection of the sensors by an order of magnitude. Importantly, this accessibility-based electrocatalytic sensing strategy is versatile and can potentially be used with other folding- and dynamics-based electrochemical biosensors.
Keyphrases
- single molecule
- living cells
- label free
- circulating tumor
- cell free
- gold nanoparticles
- nucleic acid
- low cost
- ionic liquid
- metal organic framework
- quantum dots
- molecularly imprinted
- computed tomography
- loop mediated isothermal amplification
- high resolution
- reduced graphene oxide
- photodynamic therapy
- real time pcr
- fluorescent probe