Reza Ghodssi
  Herbert Rabin Distinguished Chair in Engineering
  Director, Institute for Systems Research
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Small Scale Energy Conversion and Harvesting

 - Power MEMS Devices based on Micro-ball Bearing Technology
 - Electrochemical Energy Storage and Conversion

PowerMEMS are a class of micro-electro-mechanical systems that convert energy from one form to another. The PowerMEMS group at MSAL is currently working on micromachines supported on ball bearings, power generation, and battery technology. We have successfully designed, fabricated and characterized linear and rotary micromotors as well as the successful integration of a photodiode-based closed-loop control system for better stability and higher speeds. In addition, we have developed a 2nd-generation rotary micromotor designed to provide sufficient torque and speed to power a MEMS-fabricated viscous pump. We are conducting tribological studies in order to investigate the effect of the geometry, lubricating materials and environmental conditions on the bearing characteristics.

In the power generation and battery technology domain, we are developing novel approaches for on-chip power supply using micro-batteries and supercapacitors based on biological materials, such as the benign Tobacco Mosaic Virus (TMV) and Virus Like Particles (VLP). In parallel, we are exploring novel approaches that can measure in-situ stress/strains of battery materials in real-time.

  Chemical and Biological Sensing

 - Biofilm Monitoring and Treatment
 - Electrochemical Biosensors
 - Opto-Mechanical Biosensors

The BioMEMS group is aimed at developing systems for manipulating and detecting biomolecules on the microscale. We focus on the synergistic application of microfabrication and biotechnology. Together, they offer the potential for the creation of miniaturized devices with enhanced abilities to sense contaminants, diagnose diseases, and screen drugs.

One part of our research focuses on sensors using biomaterials to confer selectivity and enhance sensitivity. One example we are exploring is the bio-derived polysaccharide chitosan as an interface material between the organic environment and the inorganic device surface. We have developed a means to spatially localize chitosan films in specific locations by electrodeposition. These films can be covalently coupled with biorecognition molecules, allowing us to biofunctionalize micromechanical, photonic and electrochemical sensors. Another example is the use of tobacco mosaic virus and virus-like particles, which can be genetically modified to express receptors specific to target molecules. We have developed a method of selectively patterning these on microfabricated devices, again resulting in biofunctionalization. Through their rod-like structures, they also enhance sensitivity due to the large conferred surface area.

Another part of our research is the area of biofilm detection and treatment. Bacterial biofilms are the major cause of medical implant infections. Widespread use of antibiotics to treat biofilms has led to the emergence of resistant strains. There exists, therefore, a great need to enhance efficacy of existing antibiotics and develop new innovative treatment methods that can limit dose of these antibiotics. At MSAL, we have developed a biosensor for real-time biofilm growth detection integrated with an effective treatment method. This new treatment method when used in combination with low doses of antibiotics results in a significant decrease in biofilm growth. Yet another effort is to study the effects of AI-2 analogs in combination with antibiotics on biofilm growth through the use of microfluidic devices. The microfluidic device allows for precise control of the surrounding environment by providing fresh media to the biofilms, thereby very closely mimicking in-vivo environments. Efforts to study the combined effects of AI-2 analogs and electric fields on biofilm growth are currently ongoing.

  Previous Projects

 - MEMS-based Gray-scale Technology
 - Characterization of MEMS at Cryogenic Temperatures Using a Focused Ion Beam
 - Development of Micronozzles for Gas Sensing Applications