Sequence-specific DNA detection by using biocatalyzed electrochemiluminescence and non-fouling surfaces

We herein report a DNA sensor for the sequence-specific DNA detection by using glucose oxidase-based biocatalyzed electrochemiluminescence and non-fouling surfaces. In this design, a glucose oxidase-labeled sandwich-type DNA sensor was built on a non-fouling surfaces made of a mixed self-assembled monolayers (SAMs) incorporating thiolated oligonucleotides and oligo(ethylene glycol) (OEG) thiols (SH-DNA/OEG). The sequence-specific DNA sensing was accomplished by the electrochemiluminesce (ECL) signal of luminol with the in-situ generated H₂O₂. The protein-resistant non-fouling surfaces significantly suppressed the non-specific adsorption of enzyme label on electrode and reduced the background noise of this sensor. This sensor was able to detect as little as 1 pM of target DNA in pure buffer matrix. In complicated biological fluids such as human serum, this non-fouling platform-based sensor also revealed superior performance over conventional sandwich-type DNA sensors with mercaptohexanol (MCH)-coated surfaces. This strategy combines the high sensitivity of enzymatic amplified ECL and protein-resistant non-fouling platform, which is expected to be extended to a range of biological detection.