Nano Filtration and Sensing of Aminoglycosides Using Whispering-Gallery Mode Resonators

For the first time optical WGM micro resonator embedded in a microelectrofluidic system with integrated functions in sensing and nano filtration was proposed. Aminoglycosides were considered as the analyte molecules. The filtration process and analyte concentration were traced by measuring the WGM resonance frequency shift. A correlation between the frequency shift, and the analyte feed concentration and the applied voltage gradient was obtained, which reveals a linear relationship between the resonance frequency shift and the analyte concentration and an exponential growth with the applied voltage gradient. The applied voltage gradient influences the filtration capability through its effect on adsorption and desorption processes. The second-order WGM was found to be able to provide a higher sensitivity as compared with the first-order. The WGM sensor was found to function at pico Molar concentration.