Namrata Pal is a part-time Ph.D. student. The main thrust of her graduate research work is to explore impedance spectroscopy as an efficient tool to probe the alternating current (AC) conductivity of colloidal suspensions and to use this information as a guide to design novel lab-on-chip biosensors. Her recent results have demonstrated an exciting phenomenon where dilute colloidal suspensions of various different kinds show a non-monotonic conductivity behavior that is uniquely dependent on the concentration of the suspension (1).
She has also recently illustrated an immunosensor that rapidly and sensitively detects typhoid-causing infectious bacteria Salmonella enterica serovar (Salmonella typhi) in 10 μL of sample volume.(2) For this, the bacteria are tagged with gold nanoparticles (Au NPs) via high-affinity antigen-antibody interactions for enhanced signal amplification and selectivity. The cell-particle bioconjugates are then subjected to alternating current (AC) electric fields applied through interdigitated microelectrodes. The immunosensor can achieve a low limit of detection (LOD) of 100 CFU/mL. This approach is now being integrated with a portable immunomagnetic cell capture system called to iMC2 accelerate point-of-care diagnosis of bacterial infections. In this, the Au NPs have been replaced by magnetic ones are used for bacterial capture and detection in large volume samples using a combination of magnetic array and impedance spectroscopy.
- Pal N., Kumar R., Goel G. and Gupta S., ‘Concentration-dependent AC Conductivity of Colloidal Suspensions’, to be submitted (2017)
- Pal N., Sharma S. and Gupta S., ‘Sensitive and Rapid Detection of Pathogenic Bacteria in Small Volumes using Impedance Spectroscopy Technique’ Biosens. Bioelec. 77, 270-276 (2016)