UC Riverside

The development of biosensors provides effective tools for the study of life sciences and the improvement of human health. The capabilities of sensors are directly dependent on sensitivity and versatility built through smart designs. Biosensors are commonplace, including colorimentric COVID tests, electrochemical glucometers, and a variety of sensors allowing for tracking of blood oxygen level and sleeping habit. One particular technique, surface plasmon resonance (SPR), has found a broad range of usages as a label-free surface-based biosensor method with high sensitivity and real time detection, with SPR imaging further allowing for multiplexed detection. SPR has been used for kinetic analysis and drug binding assays, and relies upon the material underpinning the plasmonic effect. Further study of these materials and improvements of the plasmonic properties enhance SPR sensor technology. This Dissertation discusses theoretical and practical aspects of plasmonic sensors and the development of novel methodologies to improve the performance of SPR sensors and surface enhanced Raman spectroscopy, as well as their applications towards demanding biomedical measurement. Chapters 2, 3 and 4 focus on the development of aluminum based plasmonic sensing and the use of thin film and Kretschmann configuration for SPR measurement, which has not been previously explored as compared to the standard metal gold. Chapter 2 focuses on characterizing the fundamental optical properties of aluminum and aluminum oxide for usage as SPR sensors. Novel plasmonic behavior could be achieved with formation of an oxide waveguide that demonstrates specific sensitivity to surface and bulk changes, allowing for understanding and quantification of any surface binding events. Chapter 3 applies the confirmed concepts of the previous chapter towards a focused approach with existing SPR instrumentation, including surface characterization of aluminum thin films, and experimental confirmation of high sensitivity performance as compared to the standard gold counterpart. Chapter 4 sees the usage of the thin film aluminum substrate as an SPR biosensor in the detection of an anti-myelin associated glycoprotein, an antibody that is associated with autoimmune induced neuropathy. Chapter 5 takes a different approach to plasmonic sensors, with the fabrication of self-assembled gold nanoparticles at a liquid-liquid interface, which has been demonstrated as a SERS enhancement surface in the detection of environmental pollutants.