EAGER: Collaborative Research: Ultrasensitive frequency domain spectrometer for high throughput bacteria detection in floodwater

An award is made to Tufts University and Rensselaer Polytechnic Institute to develop a frequency domain spectrometer for high throughput tracking of bacteria in flood water in real time. In the aftermath of major catastrophic hurricanes like Harvey and Irma with winds that pull trees from their roots and roofs from houses, danger quietly continues at the microscopic level in the remaining floodwaters. This EAGER research project will advance fundamental research on sensing technology for rapid characterization of pathogenic bacteria in floodwater generated by future catastrophic events. Covering the spectrum from hybrid materials to system, there are variables and trade-offs that can only be clearly defined through methodical, directed experimentation. With this knowledge, synergistic innovations at material, device and system architecture are pursued to affect unprecedented sensor performance. The proposed cross-disciplinary research and education program will have significant broader impacts on fluorescence spectroscopy and optical sensor technology based on heterogeneous integration of nanocomposites on silicon. Instrument miniaturization will enable new studies correlating factors in water quality. Interactive workshops with biochemists and students will be organized to guide spectrometer development. There is a strong mentoring and training component for students at all levels at Tufts, RPI and the broader community.<br/><br/>The objective of this proposal is to develop a highly sensitive frequency domain spectrometer instrument for high-throughput tracking of bacteria to quantify and identify bacteria in floodwater in real time, which significantly reduces labor, time, and cost. The proposed work focuses on the spectral and temporal characteristics of intrinsic fluorescence and the material, device, and circuit innovations needed to detect them. Significant technical barriers must be overcome including optical sensitivity, wavelength selectivity, environmental robustness, interference, low-noise signal amplification, and power consumption. The proposed instrument is built on enhancements from the synergistic properties of new nanocomposites that comprise an ultrasensitive device while remaining compatible with large-scale, silicon fabrication processes. The proposed research work will benefit studies of pathogenic bacteria in floodwaters. The frequency domain spectrometer device is realized using a hybrid system-on-chip approach combining nanocomposite optoelectronic devices integrated with silicon CMOS technology for low-power, complex signal processing and bacteria classification. Silicon integrated circuit technology enables system miniaturization, resulting in an overall reduction in power consumption and parasitic components that contribute to system noise and performance degradation. This project is well suited to an EAGER grant given the innovative aspects of the proposed research program involving the merger of self-assembled nanocomposite structures, high sensitivity analog electronics, ultra-low-power multiplexing and digitization circuitry, and emerging nanofabrication techniques. The project will realize a new class of portable fluorescence spectrometers, enabling high throughput spatial and temporal correlation of fluorescence emission data for bacteria characterization unachievable with current systems. Motivated by the need to detect low level, RF-modulated optical signals over a wide dynamic range, this research project will explore the design of novel bipolar front-end analog circuitry with advanced features, including programmable gain, chopper stabilization, and offset compensation. Low-power circuit architectures for on-chip signal quantization and digitization will be explored to enable back-end digital processing for bacteria classification.