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[Illinois] ECE 416 Avidin-Biotin and Surface Functionalization I

By Brian Cunningham

University of Illinois at Urbana-Champaign

Published on


           In this lecture, we start off by taking a look at X-Ray Crystallography and how it is used to understand how biomolecules binding works. The x-ray data is processed by computer algorithms to determine coordinates of all atoms in the protein. One type of binding this has been used to see is the advin-biotin binding. Advin is a highly stable glycoprotein that has four binding sites for biotin. Biotin is a small molecule essential for metabolic reactions to synthesize fatty acids and to metabolize leucine.The interaction between the two is the strongest interaction known that is not a covalent bond. It occurs because of the hydrophobic interactions between biotin and aromatic amino acids arranged inside advin binding pockets. It is widely used in biochem. applications because of its high specific and strong binding. Other functional groups may be added to the COOH part of biotin. Bifunctional linkers can link other molecules to advin. Because the biotin molecule is so small, it won't change the function of the larger molecule it is attached to. It can be attached to every type of biosensor and nanoparticle surface. It is also a standard test to simulate detection of protein-drug interactions. Streptavidin is a similar protein to avidin, but produced by bacteria rather than animals. It is often used in assays instead of avidin. There are other methods beside avidin-biotin linkages of surface functionalism that may produce better results in some aspects and are therefore used. These include adsorption, covalent bond linkages, and hydrogel. The driving force for adsorption is the hydrophobic effects, the Vander Waals forces, and the hydrogen bonding. The disadvantages are also discussed. Covalent linkages are then discussed and how they are the strongest attachment strength. They need to make chemical bond linkages between the sensor and protein. The lysine amino acids are the usual target. The lecture ends with a revision of amine functional groups that were discussed at the beginning of the semester.


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


NanoBio Node, Obaid Sarvana, George Michael Daley

University of Illinois at Urbana-Champaign

Tags, a resource for nanoscience and nanotechnology, is supported by the National Science Foundation and other funding agencies. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.