Completed Taste Chip Research Programs - McDevitt Research Labs UT Austin

CD4 Microchips CTL (NIH)

With funding from the NIH ("Development of a Microarray for CTL Detection." Joint program with Harvard Medical School Massachusetts General Hospital with Bruce Walker, M.D.,P.I.) and Gates Foundation, our team has pioneered new lab-on-a-chip methodologies that have allowed for the first time the measurement of HIV immune function in resource poor settings. This work was recently featured in Science.

The Beckman Center for the Development of Sensor Arrays

The University of Texas at Austin secured one of the two Centers awarded Nationwide for the development of sensor array systems. Under the sponsorship of the Beckman Foundation, UT established the Center for the Design and Fabrication of Sensor Arrays (CDFSA), a facility in which the diverse skills and perspectives of natural science and engineering faculty at the University of Texas were brought to bear on challenging issues relating to quantitative chemical characterization of complex biological and environmental mixtures. To target dissimilar analyte species, a variety of molecular receptors that utilize distinct chemical sensing strategies were synthesized, and incorporated into microfabricated arrays of wells and planar chip structures. Interactions between analytes and molecular receptors were signaled through modulation of optical signals that in turn were monitored by inexpensive solid-state diode-array or video-camera technology. The measurement devices were shown to have the capability to assay many chemical species with high sensitivity in seconds, will be highly portable, and in many instances were found to yield highly specific information on chemical identities. Feasibility of a variety of important sensing methodologies were completed in this highly successful program.

ARO MURI Center for the Development of Biological Sensors

This interdisciplinary program which targeted the development and testing of new biological sensors involved the collaborative activities of ten UT faculty spread over the College of Natural Sciences and various departments from the College of Engineering. For this program, the McDevitt group served as a bridge between the macroscopic world of engineering and the microscopic aspects of biological sensing. Accordingly, work here focused on the design, construction and optimization of the components that service the taste chip platform as well as on the extension of the capacity of customized microchips. These microchip sensor efforts were targeted to the development of chemical, biological and cellular test units of relevance to important military, human medicine, environmental and homeland defense applications. Here highly functional designs for microfluidics-based flow cells were developed and tested for a variety of real-world application areas. Further, highly effective algorithms were developed that could be used to translate the array color information into analyte identity and concentration. In collaboration with the Ellington group, work was completed that allowed for the efficient adaptation of the taste chip approach for the rapid and ultra-sensitive direct detection of DNA oligonucleotides. With the Anslyn group, microchips suitable for detection of nerve agent decomposition products were fashioned. Also, membrane-based microchips were created to service a number of interesting bio-particle analysis themes. Such systems have shown utility for rapid and sensitive bacillus spore detection themes as well as for human immune function testing.

Focus Article on Biological Sensor Development (pdf).

In October 2001 anthrax spores from two contaminated letters were released into the occupied environment of the U.S. Postal Service Brentwood facility in Washington, DC. Two postal workers died from exposure to the spores and 20 others became ill. This incident reveals the vulnerability of the mail system to pathogenic bioaerosols; however, it suggests that if mail machines were equipped with detectors, not only would contamination of the postal workers and facilities be precluded, but also potential recipients of contaminated mail would be protected. Recent work from the McDevitt group at The University of Texas at Austin as well as the McFarland group at Texas A&M University has led to the development of a powerful bio-aerosol collection and detection system that is suitable for the rapid and sensitive detection of anthrax spores in postal settings. The relevant apparatus has been designed for the collection of aerosols from a critical region of the machines, and that aerosol is transported to an aerosol-to-hydrosol transfer stage, where the particulate matter is deposited into a small flow rate of liquid (about 15 drops/min). The hydrosol then flows onto a detector system developed at UT wherein a filter collects particles, exposes them to a "visualization cocktail" and then automatically detects the bio-signatures therein via optical methods. Blind tests have been completed demonstrating the efficacy of the new system using a non-hazardous stimulant for anthrax spores, bacillus subtilus. Response times below 15 minutes and spore detection thresholds less than 1000 CFU are obtained.

Neuro-pathology (Texas Advanced Research Program (ARP)

The primary goal of this Applied Research Project was to initiate the development of a cellular microarray detection system for various neuropathologies using known inflammatory bio-markers. Towards this goal, we have established bead-based fluorescent immunoassays for inflammatory cytokines, such as IL-6 and TNF-a, with relatively short incubation times and detection limits within physiological ranges enabling rapid and sensitive detection of conditions associated with neurological inflammation. Importantly, these assays now have been tested using in vitro models of cellular trauma and stimulation of inflammatory responses in cultured human glioblastoma cells.

From this work we have demonstrated that these cells respond to physiologically relevant levels of inflammatory proteins and that this response is detectable within 90 minutes following the treatment. Further, our findings support the use of these glioblastoma cells as indicators of conditions leading to neurological inflammation and demonstrate the potential of the Lab-on-a-Chip sensor, pioneered in the McDevitt laboratory, to enable further understanding and rapid detection of neurological damage or disease.