Plasmonic biosensor based on a gold nanostripe array for detection of microRNA related to myelodysplastic syndromes

Abstract

We present a new optical biosensor based on surface plasmons excited on an array of gold nanostripes via attenuated total reflection. We investigate performance of the biosensor using a theoretical model that considers both optical and mass transport aspects. The analysis of optical aspects employs two different approaches: a complex model incorporating optical characteristics of the nanostructure as well as the noise characteristics of the optical readout system and a simple model based solely on the figure of merit of the nanostructure. The theoretical analysis suggests that the optimized biosensor is able to detect molecular analytes at concentrations lower by a factor of ~ 10 than conventional surface plasmon resonance biosensors. In order to validate the theoretical model, we characterize the gold nanostripe arrays of different designs in model refractometric and biosensing experiments. We show that the nanoplasmonic sensor exhibits refractive index sensitivity of 1989 nm/RIU and refractive index resolution down to 3.6×10−7RIU. In addition, we use the nanoplasmonic biosensor for the detection of a microRNA biomarker of myelodysplastic syndromes (miRNA-125b) and demonstrate that the biosensor can detect miRNA-125b at concentrations down to ~ 17 pM.