In this lecture, we start off the discussion talking about the different functional groups. We see that the amines as bases and that carboxyl groups acts as acids. These two groups then covalently bond and eliminate H2O. Another group looked at is aldehyde where it is acidic and give up their H's and form covalent bonds with amine. This is then called glutaraldehyde which can connect the sensor to protein. The silane function is then looked at and its ability to make four bonds with a silicon center. The process for linking these proteins to a hydroxyl surface is then seen. The first step is silanization. For GOPS, a chemical, the second step would be to add protein to it and be done. For APTES, another chemical, you would expose glutaraldehyde to the silanated surface and have COOH carboxyl groups form at the ends. Then you would add protein. The linkage to the flat surface protein are separated from the transducer surface by a length of the molecular linker. It is possible to attach one monolayer of protein to the transducer surface. However, a hydrogel matrix, open porous network scaffold for immobilized protein, solves this problem. The most common type of matrix is the dextran which has a sugar, hydrophilic linear polymer, and functionalized with carboxyl groups for covalent linkage with NH2 proteins. The steps to create a sensor with the hydrogel matrix are then discussed and the results are compared with other sensors in Lofas's Paper.
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