Non-amplified impedimetric genosensor for quantification of miRNA-21 based on the use of reduced graphene oxide modified with chitosan

We report here an impedimetric genosensor for the quantification of microRNA-21 using [Fe(CN)6]3?/4? as redox probe to transduce hybridization event. The biosensing platform was built at a thiolated-gold electrode by covalent bond reduced graphene oxide (RGO) modified with chitosan (CHIT) and further attachment aminated DNA probe. GO used provide carboxylic groups CHIT and, once reduced, improve electroactivity resulting platform, while served bridge between thiol DNA. proposed bioanalytical allows label-free, non-amplified, simple fast microRNA-21, linear range 1.0 × 10?12 M 10?8 M, sensitivity (134 ± 4) ?M?1 (r2 = 0.996), detection limit 300 fM, reproducibility 5.9% miRNA-21 2.2% 10?9 miRNA-21. successfully in enriched human blood serum, urine saliva samples.