A sensitive “turn-on” fluorescent biosensor for the detection of biomarkers based on three-dimensional DNA walker

Abstract

Three-dimensional (3D) DNA walker have been widely acknowledged as a promising strategy for improving the detection sensitivity of biosensors. In this work, a sensitive “turn-on” fluorescent biosensor for the detection of biomarkers based on three-dimensional DNA walker was developed. Herein, DNA walker strands, fluorophores (FAM and Cy5)-labeled hairpin substrate strands, HER2-specific aptamer, and gold nanoparticles (AuNPs) were involved to fabricate the nanoprobe1 (nanop1) for human epidermal growth factor receptor 2 (HER2) and nanoprobe2 (nanop2) for microRNA-21 (miRNA-21). The composite fluorescent probe comprising of nanop1 and nanop2 was employed for the multiplex determination of HER2 and miRNA-21 without cross interference. This fluorescent biosensor was sensitive with the detection limits of 0.01 ng mL−1 for HER2 and 0.018 pM for miRNA-21, which was mainly due to the signal amplification of Nb.BbvcI powered 3D DNA walker. Moreover, this biosensor was selective and reliable for the detection of HER2 and miRNA-21 spiked in the serum samples. Therefore, this present 3D DNA walker-based biosensor is not only highly sensitive and specific, but also is accurate because of the multiplex detection of biomarkers, which can be expected to be used for the application in clinical field.