Seminar: Microsystems: A Bacterial Foe and a Viral Friend

In clinical applications, identifying pathogenic infections and recognizing the corresponding immune response are critical for strategizing accurate treatment. Micro-devices provide a more versatile and superior solution for biological sensing as compared to macro-scale systems, because of significant advantages like low sample volume requirement, high throughput experiments, sensitive detection and real-time monitoring. Under this scope, we have developed microsystem solutions to analyze two special biological targets: bacterial biofilms and host antibodies. Bacterial biofilms are the primary cause of severe infections of medical implants and catheters. Their complex structure composed of heterogeneous bacterial strains enveloped in an extracellular matrix necessitates the use of 500-5000 times higher concentrations of antibiotics in comparison to planktonic bacteria. A well-established method of identifying pathogens is through the antibodies produced by our body in response to the specific antigen. In this work, we give an overview of the recent developments of micro-nano-bio-systems in our group for the characterization, sensing and treatment of biofilms, as well as the accurate selective sensing of antibodies.

We have successfully demonstrated integration of organic and inorganic materials with various sensors for precise characterization and sensing of bacterial biofilms. Multi-layer valved microfluidic systems integrated with optoelectronics not only provide non-invasive spatio-temporal characterization for biofilm studies, but also parallel operation and a tightly controllable micro-environment. Surface acoustic wave microsensors and interdigitated microelectrode-based impedance sensors enable sensitive detection of the onset of biofilm formation. Integration of these sensors with treatment modules based on the bioelectric effect allows for the effective management of biofilms. We have also developed optimized methods for nanostructured sensor surfaces using genetically modified Tobacco mosaic virus-like particles (VLPs) that makes possible label-free detection of antibodies with increased sensitivity and selectivity. The VLP-functionalized optical disk resonators accurately sense minute amounts of target antibodies through refractive index monitoring. Integration of the electrical impedance microsensors with autonomous microfluidics advance this technology to further improve the real-time analysis of VLP self-assembly and quantitative measurement of target antibody attachment events. The real-time sensing platforms enabled by lab-on-a-chip technology presented above are expected to provide exciting applications of smart microsystems for both in situ biofilm detection and treatment for effective infection management, and also next generation high performance decentralized sensing of target antibodies.

About the Speaker

Reza Ghodssi is the Herbert Rabin Distinguished Chair in Engineering, Director of the Institute for Systems Research (ISR) and Director of the MEMS Sensors and Actuators Lab (MSAL) in the Department of Electrical and Computer Engineering (ECE) and the Institute for Systems Research (ISR) at the University of Maryland (UMD). Dr. Ghodssi's research interests are in the design and development of microfabrication technologies and processes in micro/nano/bio devices and systems for chemical and biological sensing, small- scale energy conversion and harvesting with a strong emphasis toward health monitoring applications. Dr. Ghodssi is a Fellow of the IEEE, AVS, and ASME, a University of Maryland Distinguished Scholar-Teacher, has more than 135 journal publications and 300 refereed conference papers, and is the co-editor of the MEMS Materials and Processes Handbook published in 2011. Dr. Ghodssi is an associate editor for the Journal of Microelectromechanical Systems (JMEMS) and Biomedical Microdevices (BMMD).

Hosted by Professor Shaurya Prakash