1.College of Chemistry and Material Science,Shandong Agricultural University,Taian,People’s Republic of China;2.College of Foreign Languages,Shandong Agricultural University,Taian,People’s Republic of China
Abstract:
5-Hydroxymethylcytosine in DNA (5hmC-DNA) plays an important biological role in sculpting the epigenetic landscape. Its presence is linked to diseases, especially cancers. The authors describe an amperometric biosensor for the determination of 5hmC. It is based on a chemical modification of the hydroxy group of 5hmC in the DNA sequence. Enzymatic signal amplification is accomplished by using DNA methyltransferase (M.HhaI-DNA-cytosine-5-methyltransferase) to achieve chemical modification. A graphene-perylenetetracarboxylic acid nanocomposite was used to modify a glassy carbon electrode (GCE) that acts as a substrate electrode. A composite consisting of horseradish peroxidase on silica/poly(acrylic acid) brushes is employed as the signal amplification unit. Under the optimized conditions, there is a linear response to the logarithm of the 5hmC-DNA concentration in the range from 0.5 to 30 nM, with a 0.23 nM detection limit (at an S/N ratio of 3) in the potential range from ?0.3 V to -0.8 V at 100 mV/s. The bioassay has excellent specificity and can even discriminate the similar base 5mC.
Graphical abstract An amperometric biosensor is fabricated for 5-hydroxymethylcytosine (5hmC) determination, where DNA methyltransferase was used to achieve chemical modification of 5hmC, and spherical poly(acrylic acid) brushes conjugated horseradish peroxidase was used as the signal amplification unit. The biosensor showed high sensitivity and specificity.
