Recent advances on signal amplification strategies in photoelectrochemical sensing of microRNAs.

As an important non-coding, evolutionary conserved, and post-transcriptional gene regulators of genome, microRNAs (miRNAs) have received extensive attention from various disciplines in the important role of biological processes and the connection with various diseases. It is also a new type of tumor marker with high specificity and sensitivity. Due to their important diagnostic values and crucial biological functions, miRNA detection attracts widespread interests. Due to the merits of low interference background, low cost, simple operation, fast response, inexpensive equipment, excellent sensitivity, and instrument miniaturization photoelectrochemical technique has been widely applied in the field of miRNA assay. As an important factor affecting the detection sensitivity, the signal amplification strategy is very important for PEC sensor. The purpose of this review is to introduce the signal amplification strategies involved into the PEC sensing filed for miRNA detection in the past five years, considering their advantages and disadvantages, and to open up new approaches in biological analysis and early disease diagnosis. The future prospects and current challenges are also discussed.