Date(s) - 26 Jan 2021 until 26 Jan 2021
2:00 PM - 3:00 PM
PhD Final Oral Exam Seminar
Graphene Biosensors for Healthcare and Food Spoilage Monitoring
Major Professor: Jonathan Claussen
Biomarker detection is a crucial step towards understanding the prognosis of a disease or health status of an individual and subsequently helps in deciding the course of treatment of a patient. Biomarkers also help in assessing the quality of a food product to minimize food wastage and the related expenses. An early and accurate detection of such biomarkers generally requires expensive laboratory techniques such as ELISA, PCR, HPLC to name a few that necessitates shipping the sample to a laboratory and time-consuming sample preparation and measurement steps carried out by trained technicians that could lead to delay in obtaining critical data of the biomarker concentration. The efforts of this dissertation are to mitigate the issues and provide faster solutions using rapid sensing assays and electrochemical detection tools such as cyclic voltammetry and electrochemical impedance spectroscopy using low cost, disposable and rapid prototyping of graphene-based printed devices to provide the test results in less than 35 minutes. The concentration of biorecognition elements is modified to meet the requirements of the sensing range, appropriate for unhealthy stages.
The focus of this work is to: 1) detect cotinine in saliva and differentiate between smokers and non-smokers in only 12 minutes and increasing the sensitivity of the sensor by 4 folds by incorporating platinum nanoparticles, 2) surface chemistry modification of high-resolution aerosol jet printed (AJP) graphene interdigitated electrodes (generally used in electronic applications) for the detection of two different cytokines, viz., interferon gamma (IFN-γ) and interleukin-10 (IL-10) for Johne’s disease in cattle and testing its robustness by mechanically bending the devices and testing their performance, and 3) detection of a common food allergen – histamine in food products such as fish fillet by modifying the antibody concentration for detection of a minimum of 50 ppm of histamine to indicate fish spoilage. All the developed biosensors did not require any sample enrichment or labelling steps making them appropriate for in-field and point-of-care applications, eliminating the need of expensive laboratory equipment and trained technicians. Apart from biosensors, such graphene devices could be widely used in energy harvesting, fuel cells and other mechanical sensors such as strain sensors.