Studies on the ssDNA-Based Biosensor Regeneration and Miniaturization for Electrochemical Detection of miRNAs

One of the most significant disadvantages of biosensing systems is the limited possibility of their regeneration, which only allows for their single use for detection of most targets. The reduction of biosensor fabrication cost could thus be achieved by elaboration of protocol providing the highest recovery of sensing layer response. A further drop of production expenses could yield the biosensor miniaturization as it leads to consumption of chemicals required for receptor layer formation as well as execution of measurements. To address the above-mentioned challenges, we aimed to find the most adequate method of regeneration of single-stranded DNA-based layers specific to miRNA 141 molecule which elevated concentration might refer to progression of cancer. The studies indicated that 5 min. incubation of ssDNA-modified electrode in 4 M urea provided the highest response towards miRNA 141 among all tested regeneration procedures. Furthermore, the possibility of ssDNA immobilization on was shown. This enabled miRNA 141 detection within 0.1 nM–1 μM concentration range with high selectivity. Moreover, ssDNA layers elaborated on miniaturized transducers were distinguished with sufficient stability after 24 h storage in 20 mM PBS and could be also regenerated using 4 M urea.