An ultrasensitive biosensor based on three-dimensional nanoporous conducting polymer decorated with gold nanoparticles for microRNA detection

•3D conducting polymers decorated with Au nanoparticles were prepared and used for electroanalysis.•The biosensor based on 3D AuNPs/PEDOT showed enlarged specific surface area and enhanced sensitivity.•The fabricated microRNA biosensor exhibited a low limit of detection of 0.38 fM.