In this lecture, assays, which is the most widely used technique to detect molecules on surfaces are discussed. In the direct assays, there is a "labeled assay" method and a "label-Free Assay" method. The Label-Free Assay method is used with most biosensor surfaces and allows a transducer to detect the presence of the antibodies. The Labeled-Assay provides a dumb surface which then provides labeling methods such as radioactive and fluorescent in order to detect the molecules. Them most popular type of assay is the Enzyme Linked Immunosorbent Assay(ELISA) which is an enzyme tag attached to the detected antibodies. There is direct ELISA which is the immobilization of the antibodies with enzymes attached and indirect ELISA which contains a secondary Antibody connected to the primary Antibody. The enzyme-substrate complex is then connected on the secondary antibody. The last method is the sandwich ELISA which has the molecule sandwiched between a capture antibody and a detection antibody. Throughout this whole process, though, the enzyme only acts as a catalase.
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 at Urbana-Champaign, Urbana, IL