Industry Viable Electrochemical DNA Detection Sensor Architecture via a Stem-Loop Methylene Blue Redox Reporter and Rapid in Situ Probe Immobilization Method for Pharmacogenetic Biomarker Testing Application

Identification of biomarkers in clinical applications for diagnostics at the point-of-care (POC) setting requires the development of industry viable biosensing platform. Herein, we report such development of biosensor architecture for the detection of pharmacogenetic biomarker HLA-B∗15:02 gene. The biosensor architecture comprises of an oligonucleotide stem-loop probe modified with a methylene blue redox (MB) reporter, immobilized via a rapid "printing"method on the commercially available disposable screen-printed electrodes (SPE). The square wave voltammetric measurements on the DNA sensor showed a clear peak difference of ∼80 nA with a significant difference in peak height values of the faradaic current generated for the MB redox moiety between the positive control (biotin-modified 19 based oligonucleotides with the sequence mimicking the specific region of the HLA-B∗15:02 allele and complementary to the probe sequence) and negative control samples (biotin-modified 19 based oligonucleotides with the sequence unrelated to the probe sequence and the HLA-B∗15:02 allele). These initial proof of concept results provide support for the possibility of using this signal-off biosensor architecture in the intended pharmacogenetic biomarker testing.