On Monday 28 September, Sriram Thoppe Rajendran will defend his PhD thesis "Development of sensors and compact, modular detection units for real-time monitoring in static conditions and in microfluidics".
Time: 13:00
Place: Zoom, sign up here: https://dtudk.zoom.us/meeting/register/u5wodO6rqzIuGtQjf2rysY8ERISCbFJDxbdE
Principal supervisor: Professor Anja Boisen
Co-supervisor: Senior researcher Kinga Zor
Co-supervisor: Associate Professor Tomas Rindzevicius
Examiners:
Professor Jenny Emnéus, DTU Bioengineering
Senior scientist Martin Hedström, Lund University
Professor Nils Paust, Hahn-Schickard
Chairperson at defence:
Associate Professor En Te Hwu
Abstract:
There is a growing demand for compact, cost efficient and user-friendly, portable analytical platforms for applications in food safety, diagnostics, environmental monitoring and quality control. In this Ph.D project, the development of modular electrochemical and optical detection units are explored.
Electrochemical sensors provide fast response, good accuracy and could be miniaturized without losing performance. The portable and affordable glucose meter, nowadays available in the pharmacies is a good example of real-life application of a medical device based on electrochemical detection, which underwent significant miniaturization and simplification during its development.
In this PhD thesis, an easy to use and compact intestine tissue-based biosensor was developed for studying the interaction of orally administered drugs with the catalase present in the intestine. With this biosensor, a new method was established for monitoring the activity of native intestinal catalase, which enabled the measurement of antioxidant capacity of drugs such as paracetamol.
Additionally, for food safety monitoring, a combination of Surface-enhanced Raman Spectroscopy (SERS) and electrochemistry was explored for achieving enhanced SERS performance. The developed, compact and modular electrochemistry-assisted SERS platform was used for quantification of melamine, a common adulterant found in dairy products. Moreover, the platform also facilitated the reusability of SERS substrates, which is significant for cost reduction.
For a truly portable and compact microfluidic analytical platform, modular detection units were developed and optimized which could be integrated with Lab-on-a-Disc (LoD) platforms. The usage of these LoD platforms is particularly advantageous as the only peripheral instrument required is a spindle motor for liquid actuation. For simplifying the integration of detection units with LoD, a modular, lightweight, disc-shaped, wireless Potentiostat-on-a-Disc (PoD) was developed. The PoD enabled real-time electrochemical detection of a model compound released from oral drug delivery devices. Furthermore, with the integration of complex valving mechanisms on the disc, the detection platform is suitable to mimic pH variations in the gut. Using the simulated gut-like pH condition, the integrity of pH coatings, used for sealing the oral drug delivery devices, could be monitored. Additionally, the modularity of the developed platform enabled the integration of optical imaging module. Using this imaging module, real-time optical detection was achieved which significantly reduced the need for peripheral instrumentation. The use of such modular detection units along with LoD opens up new avenues for compact and portable analytical systems for point-of-need / on-site detection.