[Illinois] ECE 416 Homogeneous Assays II

By Brian Cunningham

University of Illinois at Urbana-Champaign

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           In this lecture, we start with a review of the previous lecture and fluorescence polarization and dyes on homogeneous assays. The properties of fluorescent dyes are then briefly glanced over again which include absorption, emission, lifetime, polarization dependence, and transfer of photon from donor to acceptor. The last of these is then gone over in more detail in this lecture and is called Fluorescence Resonance Energy Transfer. Dye tags are usually floating on protein and there is a distance-dependant relationship between the electrons excited states of two fluorescent dye molecules. These are referred to as the donor and the acceptor. When the donor and the acceptor are brought together through the proteins they are on, the energy is transferred from the donor to the acceptor without an emission of a photon. The fluorescence output will go dark when the binding occurs. The requirements for the fluorescence resonance energy transfer to occur is for the emission spectrum of the donor to overlap the absorption spectrum of the acceptor. The distance between the donor and the acceptor must also be regulated to 1-10 nm. The molecular dipole moments for the donor and acceptor should be aligned for efficient energy transfers. The compatible donor and acceptor donor and acceptor pairs are selected and pre applied to both proteins in the process. Then, the problems with the process of the fluorescence resonance energy transfer are looked at. The lecture finishes off with examples of these processes on the homogeneous assays.


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

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Researchers should cite this work as follows:

  • Brian Cunningham (2013), "[Illinois] ECE 416 Homogeneous Assays II," https://nanohub.org/resources/17667.

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University of Illinois, Urbana-Champaign, IL


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