In-Situ Microfluidic Synthesis of Nanostructures and Their Applications for In-Channel SERS

In this Ph.D. project, microfluidics are used to manufacture and act as packaging for SERS experiments and a complete device for species analysis is created without the need for any further modification. The microfluidic fabrication techniques used to create the substrate are much more efficient than current techniques, requiring a fraction of the time and materials and allowing for both in-situ fabrication and detection to take place within the same microfluidic device. Fabrication of the SERS substrates is realized in this study using simple, cheap and efficient methods such as electrodeposition and galvanic replacement reactions. Once the fabrication of the device was complete SERS experiments were first run using crystal violet as a model testing compound, demonstrating single molecule sensitivity. Adsorption kinetics of the substrate was further studied to better understand the effects of fluid flow and the microfluidic device on the SERS signal. As a demonstration for real applications, work then focused on the detection of real world analytes and contaminants, such as pesticides and E. coli. Multiple pesticides were tested and DFT simulations were performed to better understand how the pesticides were adsorbing to the SERS surface. Finally, regeneration of the SERS substrate and the addition of other microfluidic tools, such as deterministic lateral displacement were employed in an attempt to create an entirely stand-alone, real world SERS detection system.