Studies on the application of single-stranded DNA and PNA probes for electrochemical detection of miRNA 141

The abnormal concentration of microRNAs (miRNAs) can be associated with occurrence of various diseases including cancer, cardiovascular and neurodegenerative, hence they can be considered as potential biomarkers. An attractive approach could be the application of electrochemical methods, particularly where hybridization event between single-stranded deoxyribonucleic acid (ssDNA) or peptide-nucleic acid (PNA) with miRNA strand happens. Recently, the use of various nanomaterials such as gold nanoparticles, graphene oxide, quantum dots as well as catalyzed hairpin assembly or hybridization chain reaction were proposed to further enhance the per-formance of elaborated sensors.Herein, we present the studies on selection of receptor layer composition for detection of miRNA 141. The possibility of formation of receptor layer and further duplex monolayer between ssDNA or PNA with miRNA was analyzed by atomic force microscopy (AFM) technique. The interaction of ssDNA and PNA probes with miRNA was further verified using surface plasmon resonance (SPR) and quartz - crystal microbalance (QCM) techniques. On the basis of impedance spectroscopy it was shown that the use of unlabelled ssDNA as receptor layer provided 0.1 pM detection limit. This shows that proposed biosensor that is simple in preparation and use is an attractive alternative to other recently presented approaches.

Automated summary

The abnormal concentration of microRNAs can be used as potential biomarkers for various diseases, and electrochemical methods, especially those involving hybridization with single-stranded DNA or peptide-nucleic acid, show promise in their detection. Recent studies have explored the use of nanomaterials and catalyzed reactions to enhance the performance of these sensors. This study focused on the selection of a receptor layer composition for the detection of miRNA 141, using atomic force microscopy, surface plasmon resonance, and quartz-crystal microbalance techniques to analyze the formation of the receptor layer and the interaction between the probes and miRNA. Impedance spectroscopy showed that the use of unlabelled ssDNA as the receptor layer provided a detection limit of 0.1 pM, suggesting that this biosensor is a simple and effective alternative.