(Invited) Plasma Assisted Enhancement in Optical and Electronic Properties of Metal Nanoparticles: Application in Electrochemical Biosensing

Abstract

In surface-modified biosensing, the performance of the sensor depends on the surface architecture. Hence, the quantification of the NP coverage on the electrode surface becomes vital when it comes to NP-based sensing. The sensitivity enhancement of biosensors can be achieved by increasing the active surface area using nanoparticle-functionalized electrodes. However, these enhancements have certain limitations due to a lack of information about the properties of nanoparticles and their behavior under certain conditions arising due to polydispersity, orientation, and surface roughness. In this work, the enhancement in the sensitivity of cortisol biosensors has been achieved by increasing the active surface area using nanoparticle (NP)-functionalized electrodes as they exhibit higher electric field intensities. The plasma-assisted NP functionalized electrodes displayed higher electrochemical performance due to plasma-assisted surface activation of NPs. However, as the improved NP coverage was observed in plasma-assisted NP deposition, this might also be the reason for the enhancement of the electrochemical properties, electroactive surface area, and sensitivity. This study also presents the plasma-induced enhancement of electrical properties of Au NPs at room temperature. The distribution of plasma-assisted aerosolized deposited NPs showed the promising architecture for surface modification of the electrochemical sensor that has improved the electrochemical sensing, which is validated by detecting the cortisol molecules. This improved electrochemical response is due to plasma-assisted surface activation of NPs.