In this lecture, we continued our discussion on Surface Enhanced Raman Spectroscopy (SERS). We started off with a revision of the previous lecture and focused on the important concepts like the two important wavelengths: the wavelength from the laser and the emitted scattered wavelength. The review also included a revision of Metal Film Over Nanoparticles, but included more details. After that, the lecture moved on to looking at the difference between the different types of metal surfaces and the advantages/disadvantages from each. The lecture then moved on to the application of the SERS in Glucose Sensing. For glucose sensing, the Metal Film Over Nanoparticle technique is used to measure glucose, from blood, but there are a lot of other molecules too so a "partition" coating is put to prevent large molecules from reaching the SERS active region. However, the partition coating will generate a SERS signal that must be accounted for. There are problem in the SERS method like the presence of other molecules competing for Raman signatures, interfering molecules can covalently bond with the metal surface and permanently foul it, and there is a strong fluorescence background involved. One of the biggest disadvantages are the size and cost and the fact that people will need to be implanted with optical windows in order to measure and read results. The SERS can be used for pathogen detection, forensic, and detection of metabolites in body fluids. Then, we look at results from Professor Cunningham's group and their work on In-line sensors for Biomedical Tubing. The detection of urea results with SERS are then observed. The lecture concludes with the analysis of the data from the detection of promethazine using the SERS technology.
My research group is focused on the application of sub-wavelength optical phenomena and fabrication methods to the development of novel devices and instrumentation for the life sciences. The group is highly interdisciplinary, with expertise in the areas of microfabrication, nanotechnology, computer simulation, instrumentation, molecular biology, and cell biology. In particular, we are working on biosensors based upon photonic crystal concepts that can either be built from low-cost flexible plastic materials, or integrated with semiconductor-based active devices, such as light sources and photodetectors, for high performance integrated detection systems.
Using a combination of micrometer-scale and nanometer-scale fabrication tools, we are devising novel methods and materials for producing electro-optic devices with nanometer-scale features that can be scaled for low-cost manufacturing. Many of our techniques are geared for compatibility with flexible plastic materials, leading to applications such as low cost disposable sensors, wearable sensors, flexible electronics, and flexible displays. Because our structures manipulate light at a scale that is smaller than an optical wavelength, we rely on computer simulation tools such as Rigorous Coupled Wave Analysis (RCWA) and Finite Difference Time Doman (FDTD) to model, design, and understand optical phenomena within photonic crystals and related devices.
In addition to fabricating devices, our group is also focused on the design, prototyping, and testing of biosensor instrumentation for high sensitivity, portability, and resolution. Advanced instruments enable high resolution imaging of biochemical and cellular interactions with the ability to monitor images of biochemical interactions as a function of time. Using the sensors and instrumentation, we are exploring new applications for optical biosensor technology including protein microarrays, biosensor/mass spectrometry systems, and microfluidics-based assays using nanoliter quantities of reagents. The methods and systems developed in the laboratory are applied in the fields of life science research, drug discovery, diagnostic testing, and environmental monitoring. -From Professor Cunningham's Faculty Profile
University of Illinois, Urbana-Champaign, IL