Ultrasensitive electrochemiluminescence biosensor constructed by luminol-diazonium ion functionalized Au/MXene nanocomposites for early stage detection of disease in human

ABSTRACT MicroRNAs (miRNAs) are important biomarkers for tracking occurrence and development of many diseases, therefore, the reliable, sensitive, fast and accurate detection of miRNAs plays an extremely critical role in clinic diagnosis and treatment of early stage diseases. Herein, we developed ultrasensitive electrochemiluminescence (ECL) biosensor constructed by luminol-diazonium ion functionalized Au/MXene nanocomposites for early stage detection of kidney disease in human. The synergistic effect of MXene and Au nanoparticles significantly enhanced the ECL emission of luminol up to 6.9-fold due to their shortened electron transfer distance and excellent catalytic performance. The loading efficiency of luminol on MXene could be as high as ∼7%, enabling the enrichment of luminol on MXene nanosheets. The enhanced ECL signal and excessive loading of luminol allowed the Au-MXene-luminol as an excellent ECL labeling agent, which was further developed for the determination of miRNA-377 according to the sandwich-like assay. The as-developed miRNA-377 biosensor had ultrahigh sensitivity, wide linear range (from ∼50 aM to ∼1 nM), low limit of detection (∼13.2 aM) and high selectivity (∼82.6%) for highly homologous miRNA with mismatched single-bases. The ultrasensitive ECL biosensor was successfully applied to determine miRNA-377 in the serum samples of early stage kidney patients, which were well consistent with the clinic standard of quantitative real-time polymerase chain reaction method. The ultrasensitive ECL-labeling biosensor with high selectivity is very promising for universally screening any kinds of biomarkers with corresponding specific targets.