A novel signal-on photoelectrochemical biosensor for detection of 5-hydroxymethylcytosine based on in situ electron donor producing strategy and all wavelengths of light irradiation

In this paper, a novel signal-on photoelectrochemical (PEC) biosensor was papered for detecting 5hydroxymethylcytosine (5-hmC) based on in situ electron donor producing strategy and all wavelengths of light irradiation. Firstly, the amino modified double DNA strand containing 5-hmC was captured on the carboxyl functionalized magnetic bead surface via amide linkage. After treatment with cysteamine in the presence of M.HhaI, the dsDNA with 5-hmC could transformed to amino-derivatized DNA. Subsequently, NHS-biotin could be labeled on the amino-derivative dsDNA and further reacted with avidin conjugated alkaline phosphatase (avidin-ALP). Under the catalysis effect of ALP toward ascorbic acid 2phosphatetrisodium salt (AAP), ascorbic acid (AA) was in situ produced as electron donor. After magnetic separation, the biosensor can achieved all wavelengths of light irritation and a strong PEC response was obtained using a CdS/ITO as working electrode. The prepared biosensor showed high detection sensitivity with low detection limit of 0.167 nM for 5-hmC. (C) 2015 Elsevier B.V. All rights reserved.