In this lecture, we look at the concepts and theories behind the acoustic wave sensor. This sensor communicates through the vibrational waves in matter. The atoms in the system are displaced, causing an Internal Elastic Restoring Force. This is the vibration that transmits the acoustic waves. The waves transmission are able to detect the biomolecules through the change in the frequencies. A piezoelectric mass, materials that produce oscillation and generate output, has antibodies placed on it and as the target molecules attach themselves to these molecules, the mass of the piezoelectric material changes. An electric field is being placed through the material and the voltage potential can be measured and tell the changing of the frequency of the system. The piezoelectric material is a transducer that converts mechanical energy to electrical energy. To determine the resonant frequency for oscillation, a voltage is needed to be applied and adjusted until the maximum voltage output is found. The best way for the electric field to go through the piezoelectric material is through shear stress. This brought about the Thickness Shear Mode Biosensor, in which there antibodies on a quartz(as piezoelectric material) and there is oscillator circuit in which the more mass there is, the lower the vibrations.
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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University of Illinois at Urbana-Champaign, Urbana, IL