Proposal Number: 0529132 Principal Investigator: Sandra Troian Affiliation: Princeton University Collaborative Research - SST: Integration of Spectroscopic Sensors and Electroactive Nanowell Arrays with Microfluidic Chips Based on Thermocapillary Actuation
Microfluidic devices for liquid dosing, transport and mixing are driving innovation in genomic and pharmaceutical research as well as rapid commercialization of portable kits for home, industrial or military use. Such devices, predicted to revolutionize portable chemical detection and analysis, are expected to generate over 2 billion dollars in income by 2010. The newest open format devices, based on actuation of free surface flows, i.e. liquid-liquid or gas-liquid interfaces, provide an especially attractive platform for highly sensitive detection of adsorbed species. Essential to the operation and control of these devices is development and integration of sensing arrays for high resolution, autonomous identification of sample position, volume, temperature, speed, composition and molecular species. This research program targets the development and integration of miniaturized optical, spectroscopic and electroactive sensors with thermofluidic chips. The three-part program includes (a) integration of thin film waveguides with open fluidic devices for evanescent sensing of stationary or moving samples, (b) development of a novel liquid-core waveguide based on thermocapillary actuation of microscale rivulets and (c) development of electroactive nanowell traps for electrostatic confinement and concentration of biomolecules. The waveguide sensors will be used to monitor droplet location, composition, rate constants for chromogenic reactions, and binding to functionalized quantum dots in a liquid suspension. Additional signal enhancement will be explored through evanescent coupling to micro-ring or micro-disc resonators fabricated on the chip surface. The electroactive nanowell sensor arrays positioned beneath stationary or moving droplets will allow development of an electrical impedance spectroscopic technique for use as an environmental sensor of aqueous borne bacterial pathogens. Sensor development and optimization will proceed through experiment, theoretical modeling and numerical simulations. The broader impacts of this grant are as follows: The interdisciplinary nature of the research will allow development of a novel fluidic chip with integrated sensing arrays and provide students with unique training at the crossroad of microscale transport phenomena and photonics, two high growth areas with numerous applications to bio- and nanotechnology. Undergraduates will be recruited through the NSF REU programs at Cornell and Princeton to aid with chip and nanowell fabrication, assembly of simple prototypes and data analysis. Students will be trained in the physical and engineering principles governing advanced optical and electrokinetic sensing platforms; they will also develop demonstration units for undergraduate lab courses and K-12 education. The Princeton PI will expand a current course on microfluidic phenomena to include a 2nd semester on sensing principles for miniaturized devices. She will also be leveraging this study toward establishment of a new Princeton Center on Advanced Fluidic Technologies, a large scale pilot program currently under consideration by the New Jersey Commission on Jobs Growth and Economic Development The Cornell PI will design a new course geared toward modern engineering and fabrication techniques of optical and spectroscopic sensors for lab-on-a-chip technologies. The PIs will jointly organize sessions on optofluidics and sensing at the IEEE Tranducers and SPIE Optical Information Systems meetings.
