The main goal of this thesis is to fabricate a PDMS-based microfluidic Lab-On-a-Chip (LOC) with polyacrylonitrile (PAN) nanofibers inside the channels to facilitate micro-RNA (miRNA) capture. The designed and developed device is oriented, in a viral detection context, to the execution of tests with RNA immobilization and amplification with an isothermal amplification method. The good properties of PDMS were exploited, namely the biocompatibility, the versatility and the stickiness it exhibits with a very wide range of materials, including polymer-type nanofibers. The main technological challenge was to integrate nanofibers inside the microfluidic channels, thus exploiting their intrinsic characteristics: high surface-to-volume ratio and high porosity per unit mass.