Construction of a Dye-Sensitized and Gold Plasmon-Enhanced Cathodic Photoelectrochemical Biosensor for Methyltransferase Activity Assay.
Lin CuiJingzhu ShenChen-Chen LiPei-Pei CuiXi-Liang LuoXiaolei WangShuangshuang ZhangPublished in: Analytical chemistry (2021)
DNA methyltransferases may function as important biomarkers of cancers and genetic diseases. Herein, we develop a dye-sensitized and gold plasmon-enhanced cathodic photoelectrochemical (PEC) biosensor on the basis of p-type covalent organic polymers (COPs) for the signal-on measurement of M.SssI methyltransferase (M.SssI MTase). The cathodic PEC biosensor is constructed by the in situ growth of p-type COP films onto a glass coated with indium tin oxide and the subsequent assembly of biotin- and HS-labeled double-stranded DNA (dsDNA) probes onto the COP film via biotin-streptavidin interaction. The dsDNA probe contains the recognition sequence of M.SssI MTase. The COP thin films possess a porous ultrathin nanosheet structure with abundant active sites, facilitating the generation of a high photocurrent compared with the hydrothermally synthesized ones. The presence of DNA methyltransferases can prevent the digestion of restriction endonuclease HpaII, consequently inducing the introduction of gold nanoparticles (AuNPs) to the dsDNA probes via the S-Au bond and the intercalation of rhodamine B (RhB) into the DNA grooves to produce a high photocurrent due to the dye-photosensitized enhancement and AuNP-mediated surface plasmon resonance. However, in the absence of M.SssI MTase, HpaII digests the dsDNA probes, and neither AuNPs nor RhB can be introduced onto the electrode surface, leading to a low photocurrent. This cathodic PEC biosensor possesses high sensitivity and good selectivity, and it can screen the inhibitors and detect M.SssI MTase in serum as well.
Keyphrases
- gold nanoparticles
- sensitive detection
- single molecule
- quantum dots
- circulating tumor
- label free
- nucleic acid
- cell free
- living cells
- small molecule
- reduced graphene oxide
- visible light
- highly efficient
- high throughput
- fluorescent probe
- room temperature
- wastewater treatment
- aqueous solution
- gene expression
- binding protein
- computed tomography
- pet imaging
- silver nanoparticles
- dna repair
- metal organic framework
- dna methylation
- photodynamic therapy