A label-free genetic biosensor for diabetes based on AuNPs decorated ITO with electrochemiluminescent signaling

The variation of I27L gene closely relates to increasing risk of type 2 diabetes, thus it is greatly significant to develop various methods for its identification or monitoring. We report here a novel label-free electrochemiluminescent (ECL) biosensor for simple and effective determination of I27L gene based on Au nanoparticles functionalized ITO electrode. The ECL technique is employed to monitor the hybridization of DNA strands by measuring the changes of its intensity. Here, the ECL signal was quenched by blocked access of probe (luminol anion) owing to the electrostatic repulsion of negatively charged sensor surface and the space resistance. The quantification of target strand can be directly realized by calibrating the quenched ECL signal toward its logarithm concentration in good linearity within the range from 1.0 × 10^-11 to 1.0 × 10^-7 M and a detection limit of 8.1 × 10^-12 M. In addition, the biosensor exhibited good stability, excellent reproducibility and outstanding selectivity against one-base mismatched strand. What's more, the simple, low-cost, sensitive device could be easily miniaturized, makes it as an attractive candidate for integrating into portable platforms for point-of-care molecular diagnostics.