Integrated Biomedical Sensors

Axel Scherer, Distinguished Visiting Professor, Thayer School of Engineering

Friday, May 14, 2010, 3:30pm

Spanos Auditorium

This seminar is part of the Jones Seminars on Science, Technology, and Society series

Lithographically defined electronic, fluidic, and optical systems can be integrated to create diagnostic microdevices. Indeed, biomedical devices today can be constructed by two- and three-dimensional soft and hard lithography, in which pico-Liter volumes can be manipulated and analyzed. Compact and efficient immuno-assay chips, cell analysis chips and pathogen identification systems have evolved. In the near future, we can expect similar success from lithographically integrated opto-fluidic, optomechanical, magnetooptical and magneto-fluidic systems. Our recent devices have been evaluated for health-care applications, and the opportunities of integrated sensor systems for diagnostic purposes will be explored. For example, we have developed qPCR amplification techniques that can be used for rapid diagnosis of viruses and other pathogens, demonstrated amplification of 10 microliter clinical samples within 90 seconds, and optimized single-cell analysis chips in which the RNA libraries of up to 30 individual cells can be analyzed and compared. We also use microfluidic systems for human blood serum analysis. Presently, we are developing cancer screening panel test in which 10 antibody reactions are used in parallel to ensure inexpensive serum analysis. We also integrate microfluidics with nanophotonics for spectroscopy systems to determine concentrations of gases and ions in solution, and develop micro-thermometers and heaters based on platinum wires. As part of this effort, we are building on-chip light-bulbs for visible and infrared spectroscopy sources. To reduce the overall size of diagnostic systems, we introduce electro-chemical dissociation to generate pressure on-chip with low power Pt electrodes and shape memory alloy micro-valves and micro-pumps to replace expensive pneumatic control circuitry. Finally, we have developed silicon nanowire transistors for sensitive chemical nano-sensors. The improvement of microfluidic control and the maturity of nanophotonic devices for spectroscopic applications now enable us to define new classes of miniaturized chemical and biological sensors. To this combination, we can add electrical power generation, measurement and control systems in order to meet the needs for implantable sensor systems.

About the Speaker

Axel Scherer is the Bernard A. Neches professor of electrical engineering, applied physics and physics at Caltech and the Co-Director of the Kavli Nanoscience Institute. Professor Scherer's research focuses on the development and application of new microfabrication and design methods. In the 1980s, Professor Scherer pioneered the development of vertical cavity lasers, which have become a commercial success. In the 1990s, his group developed some of the first silicon photonic circuits, optical nanocavities, and integrated microfluidic devices. Fundamentally new structures, such as photonic bandgap geometries, resulted in some of the world's smallest lasers, modulators, and waveguides. At the moment, Professor Scherer is interested in the miniaturization and integration of microfluidic, magnetic, and optical devices for applications in nano-biotechnology. His group also explores the limits of lithography at the nanometer scale. Professor Scherer has co-authored over 300 publications and holds over 60 patents in nanofabrication related areas. He is presently at Dartmouth as a visiting faculty on sabbatical.