Refractive index tuning of SiO₂ for Long Range Surface Plasmon Resonance based biosensor

A novel, highly sensitive and low cost Long Range Surface Plasmon Resonance (LRSPR) biosensor for detecting uric acid, as a model analyte, has been developed in this work. Silicon dioxide (SiO₂) having low and tunable refractive index has been chosen as the dielectric layer for the excitation of LRSP modes replacing the most explored Cytop and Teflon polymers. The prepared LRSPR based uric acid bio-sensor gives good response characteristics with a high sensitivity of about 21.6°/mM and low limit of detection (LOD) of 0.02 mM. The fabricated LRSPR sensor was also evaluated to detect uric acid in real serum samples. The results yield a great scope to promote the development of robust, efficient and highly selective LRSPR based biosensors with SiO₂ as tunable dielectric layer.