An efficient electrochemical assay for miR-3675-3p in human serum based on the nanohybrid of functionalized fullerene and metal-organic framework.

Idiopathic pulmonary fibrosis (IPF) is an interstitial lung disease with unclear pathogenesis, for which diagnosis has been a great challenge. Recent researches have revealed that miR-3675-3p is a promising biomarker for IPF diagnosis. Herein, the present work describes a novel electrochemical microRNA biosensor for rapid and sensitive detection of miR-3675-3p based on multiple signal amplification strategies. First of all, fullerene (C60) is doped with poly(amidoamine) (PAMAM)-functionalized metal-organic framework (MOF) to form a new nanohybrid of C60@PAMAM-MOF, which exhibits more remarkable redox activity compared with the other two synthesized C60-based nanohybrids when triggered by tetraoctylammonium bromide (TOAB). C60@PAMAM-MOF also possesses a large specific surface area and abundant amino groups to anchor Au nanoparticles (AuNPs) for the immobilization of signal probe (SP) to form tracer label and enhance the electrochemical response signal. In addition, core@shell Au-Pt nanoparticles (Au@PtNPs) are absorbed on chitosan-acetylene black (CS-AB) to act as sensing platform, which can promote electron transfer and increase the loading of capture probe (CP). Under optimum conditions, the proposed biosensor displays a wide linear range for miR-3675-3p from 10 fM to 10 nM, with a limit of detection (LOD) as low as 2.99 fM. More significantly, this biosensor shows a lower LOD and wider linear range than that of qRT-PCR, and its trial application in human serum shows favorable results, which exhibits a promising prospect for IPF diagnosis.