Naked eye detection of lung cancer associated miRNA by paper based biosensing platform

This letter demonstrates a biosensing platform for naked eye detection of miRNA, fabricated using a poly(vinylidene fluoride) thin paper impregnated with positively charged poly(3-alkoxy-4-methylthiophene) as luminescent reporters. The miRNA assay is based on the formation of a duplex and a triplex species between the "reporter and miRNA" and "reporter and miRNA-peptide nucleic acid (PNA) hybrid", which yields two significantly different optical signals, thereby facilitating naked eye detection. This letter illustrates the successful validation of the proposed methodology via a mir21 assay (miRNA sequence associated with lung cancer). Furthermore, this facile platform enables rapid, sensitive, and selective detection of miRNA, at clinically relevant concentration levels as well as single base pair mismatch, without requiring complex and expensive instrumentation.