Implanting a Fluorescence Microscope: How VLSI Can Change Biomedical Research

Increasingly, biologists are discovering that pathologies such as cardiovascular disease and cancer involve complex interactions between pathogenic cells and reactive neighboring cells via multiple chemical pathways and enzymes. A variety of highly specific fluorescent probes are available to identify the cells and enzymes involved and visualize these chemical processes, but the microscopes for imaging these probes is poorly suited to the in vivo imaging required to observe these interactions. This talk will demonstrate how a VLSI system can replace the bulky components of traditional microscopes with integrated circuit alternatives to serve as an implantable fluorescence microscope. Magnifying optics of traditional microscopes are replaced by pixels smaller than cells for high resolution contact imaging. Interference filters for channel separation are replaced by time-domain methods requiring nanosecond-time-scale pixels. Cables and knobs that provide power, input, and output are replaced with a single channel of wireless communication and decoding logic.

Dr. Christopher Salthouse received his bachelor's and master's degrees in Electrical Engineering from the Massachusetts Institute of Technology in 2000. He continued at MIT in Prof. Rahul Sarpeshkar's Analog VLSI and Biological Systems Group developing micropower integrated circuits for cochlear implant speech processors and hearing aid preprocessors. After receiving his Ph.D. in 2006, he moved to the Massachusetts General Hospital where he is currently working with Prof. Ralph Weissleder in an interdisciplinary group including physicians, chemists, biologist, and engineers to develop new biomedical imaging methods. At MGH, he has developed a technique for fluorescent lifetime separation of spectrally matched fluorophores, the first lensless fluorescence microscope, and the first continuous wave laser based two-photon small animal imager.