Electroanalysis offers several unique advantages such as simplicity, sensitivity, low-cost, selectivity, automation, and miniaturization. In order to successfully extract some or all of these advantages for analysis of desired compounds, the surface design of electrodes and detection mechanisms need to be worked out. In this regard, carbon nanostructure modified electrodes have been known for a while now for development of sensitive electrochemical biosensors and biocatalytic systems. We have been able to make some unique contributions in the measurements of serum insulin levels relevant to type 1 and type 2 diabetes conditions, serum autoantibodies as prospective early diabetes markers, urine formaldehyde levels, enzyme-specific drug activity assay, and single drop electroanalysis of oxidative pharmaceuticals. Specifically, we designed covalent and non-covalently functionalized carbon nanotubes and magnetic nanomaterials in our immunoassays and enzyme bioelectrode designs to selectively oxidize drugs or for the detection of various biological analytes. Quantitative insights on the functionalization and surface immobilized amounts of biomolecules were obtained. Research findings from these projects will be discussed in this presentation.

Representative References.

1. Singh, and S. Krishnan, Electrochemical Mass Sensor for Diagnosing Diabetes in Human Serum, Analyst 2014, 139, 724 – 728.
2. Walgama, N. Means, N. F. Materer, and S. Krishnan, Edge-to-edge Interaction between Carbon Nanotube-Pyrene Complexes and Electrodes for Biosensing and Electrocatalytic Applications, Phys. Chem. Chem. Phys. 2015,17, 4025-4028.
3. Singh, and S. Krishnan, Voltammetric Immunosensor Assembled on Carbon-Pyrenyl Nanostructures for Clinical Diagnosis of Type of Diabetes, Anal. Chem. 2015,87, 2648-2654.
4. Singh, C. Rodenbaugh, and S. Krishnan, Magnetic Optical Microarray Imager for Diagnosing Type of Diabetes in Clinical Blood Serum Samples, ACS Sensors 2016, 1, 437-443.
5. Niroula, G. Premaratne, S. A. Shojaee, D. A. Lucca, and S.Krishnan, Combined Covalent and Noncovalent Carboxylation of Carbon Nanotubes for Sensitivity Enhancement of Clinical Immunosensors,Chem. Commun. 2016, 52, 13039-13042.
6. Walgama, M. Gallman, and S. Krishnan, Single Drop Electroanalysis and Interfacial Interactions: Sensitivity versus Limit of Detection, Electroanalysis 2016, 28, 2791-2796.
7. Premaratne, S. Farias, and S. Krishnan, Pyrenyl Carbon Nanostructures for Ultrasensitive Measurements of Formaldehyde in Urine, Analytica Chimica Acta, 2017, 970, 23–29.