Silica nanoparticle based label free impedance immunosensor: Role of particle size in sensitivity enhancement

摘要

This paper investigates the impact of incorporating silica nanoparticles of varying diameters in label free impedance immunosensor. It has been observed that even if the surface area improvement has been adjusted to be similar for all the diameters, the sensitivity is enhanced by five times at a particular diameter of 100 nm due to the optimum combination of intersection with electric field lines and surface convexity. This study has enabled the detection of 0.04 fM Hep-B surface antigen with a reliable sensitivity of around 75% which is 275% higher compared to a recent report.