Development of a miRNA biochip platform

MicroRNAs (miRNAs) are short noncoding RNA molecules involved in the regulation of carcinogenesis. Tumor-derived miRNAs will be released into the circulation, and these miRNAs, also known as circulating miRNAs, have stable properties in plasma and serum. Thus miRNAs have been suggested as a potential biomarker for cancer diagnosis. The aim of this study was to develop a miRNA biochip platform. First, we used three types of reverse transcription (RT) primers; we constructed the miRNA-containing poly(A) tail and used RT primer oligo(dT) to make the complementary DNA (cDNA), and we also designed a linear-form RT primer and a stem-loop RT primer to synthesize cDNA. Second, we selected 11 candidate miRNAs related to colorectal cancer (CRC) from our previous studies and then designed the probes based on the sequence of the candidate miRNAs and constructed a miRNA biochip. miRNAs were extracted from CRC cell line SW620 and were detected by enzymatic biochip assay. According to the results, we found that this miRNA biochip can effectively detect the miRNAs by using a specific stem-loop RT primer to synthesize cDNA. In the future, we will design more oligonucleotides for miRNA detection and also evaluate the consistency between the results of the miRNA biochip and quantitative real-time polymerase chain reaction (PCR).