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John McDevitt
Brown-Wiess Professor of Chemistry and Bioengineering
John T. McDevitt is a pioneer in the development of “integrated nano-bio-chip” technologies.Efforts in this area have the potential to replace high-cost, lab-based, and time-consuming diagnostic tests with inexpensive, battery-powered diagnostic devices with immense clinical impact– especially in developing countries and remote settings where traditional laboratory measurements are not practical. One of these nano-bio-chip systems used for salivary testing in prehospital settings for heart attacks was just selected by Popular Sciences for the Best of What’s New (2008) in the Medical Devices category.
In 1996, McDevitt developed the concept for and launched a research program directed towards microchip-based technology suitable for the rapid analysis of complex fluids. His basic science and dedication to the translation of research prototypes led to the development of two new classes of mini-sensors for measuring and analyzing solutions that contain a wide range of biological and nonbiological analytes including toxins, drugs, metabolites, bacteria and blood products. His work led to one of the largest patent portfolios in the history of the University of Texas (UT) at Austin. Two centers, the Beckman Center for Chemical Sensors and the Army Research Office MURI Center for Biological Sensors, were established at UT to support these efforts.
Currently, McDevitt is a principal investigator for a large, multi-site clinical program sponsored by the National Institute of Dental and Craniofacial Research (NIDCR), part of the National Institutes of Health. The project targets the development and application of next-generation salivary diagnostic devices for oral and systemic diseases such as cardiac, stroke and cancer applications. His research at Rice uses nanometer-sized building blocks to develop extremely tiny sensors that may be described as “lab-on-a-chip” systems.
McDevitt’s research has been supported by significant funding from the NIH, the Bill and Melinda Gates Foundation, the Welch Foundation, the Doris Duke Charitable Foundation, the NSF, the Office of Naval Research, and others. His work has been highlighted in more than 160 peer-reviewed manuscripts; has been featured in Science, Business Week, and Popular Science; and on NIH Web sites. He has authored more than 150 patents and patent applications. These innovations were selected as part of the Science Coalition’s Best Scientific Advances in 1998, and he has received a number of notable awards including the Presidential Young Investigator Award, and the Exxon Education Award.
In 2004, McDevitt co-founded LabNow in Austin, TX based on the CD4 microchip technology developed in his laboratories that provides simple, rapid, and affordable methods for counting white blood cells in HIV/AIDS patients. The immune function nano-bio-chip device has successfully completed human trials in Boston hospital settings and in an HIV reference laboratory in Botswana, Africa. McDevitt serves on advisory boards for LabNow and the NIH.
Research Statement
A long-standing research interest of the McDevitt group is the science and engineering of hybrid molecular assemblies as applied to sensor and device applications. Research efforts are underway to translate these discoveries into forms that are practical and scalable for use as real-world sensors for humanitarian and civilian applications. These highly sensitive and selective sensor systems have begun to serve as powerful diagnostic tools that have enabled new clinical studies to be completed that were not previously thought possible. The following are brief summaries of the activities currently in progress in the McDevitt laboratories that utilize these novel nano-bio-chip platform systems.
CARDIUS (Cardiac Arrest Rapid Diagnostic Information Using Saliva)
According to a recent report by the American Heart Association (Rosamond et al. Circulation, 117 (4): 2008), cardiovascular disease remains the leading cause of death in developed countries. Coronary artery disease (CAD), the precursor to many heart attacks, causes 1 of every 5 deaths in the United States. In 2008, an estimated 770,000 Americans had a new coronary attack, and about 430,000 are expected to have a recurrent attack within the next year.
Leveraging microelectronics components and microfabrication developed initially for the electronic industry, the McDevitt laboratory and collaborators have developed a series of compact nano-bio-chip sensor devices that are cost effective and yield ultra-powerful diagnostic capabilities. The nano-bio-chip sensors are biochemically programmable and, as such, can be fashioned to detect numerous proteins in saliva that offer diagnostic utility. Recent activities have led to the identification of diagnostic panels for identifying a patient’s risk for primary cardiac events as well as for diagnosing an actual heart attack when it happens. This CARDIUS technology, which contains all necessary reagents on a device the size of a credit card, produces equivalent results to clinical laboratory blood tests in as little as 15 minutes using a few drops of saliva.
Nano to global diagnostics program
Infectious diseases remain the leading killers of human beings worldwide and function to destabilize societies in Africa, Asia and the Middle East. In 2001, the Joint United Nations Program on HIV/AIDS (UNAIDS) and the World Health Organization (WHO ) reported that by the end of 2007, approximately 33 million people were expected to be living with HIV/AIDS worldwide.
Today there is no cure for HIV/AIDS, but there are important treatments that contain the effects of HIV. Effective drug cocktails based on highly active anti-retroviral therapy or HAART have transformed the treatment and management of HIV patients on a global basis. While rapid HIV tests are now available in numerous resource-poor settings including Africa, the CD4 monitoring tests that accompany HAART treatment are missing for over two thirds of the persons in Africa.
This program targets the development, testing, and deployment of a powerful nano-bio-chip-based technology suitable for the early detection, monitoring and tracking of emerging infectious diseases. Customized lab-on-a-chip systems developed by the McDevitt group have found utility for the measurement of CD4 counts for the assessment of HIV immune function and are suitable for use in resource-poor settings. Future efforts in the area will strive to develop a panel of strategic HIV diagnostic tools that may be used at the point of need.
Biochip center for immune function monitoring
An equipment infrastructure that is suitable for clinical measurements of the immune function has been established within the McDevitt laboratory. Portable instrumentation developed through this program is being tested and validated against the established gold standard approaches. Particular emphasis has been placed on assays such as CD4 and viral load measurements of HIV+ patients. Furthermore, the establishment of a Biochip Center for Immune Function Monitoring will serve an important role in defining the equipment needs for future generations of cost-effective medical instrumentation that is functional at the point-of-care both in the U.S. and resource-poor settings.
Pathology on a chip- oral cancer diagnosis
This year about 34,000 Americans will be diagnosed with oral or throat cancer. These types of cancer will result in over 8,000 deaths, or about 1 person every hour, 24 hours a day, 7 days a week. Of the 34,000 newly diagnosed oral cancer patients, only half will be alive in 5 years. The prognosis for this group of cancer patients has not significantly improved over the last few decades. Worldwide the problem is much greater with over 350,000 new cases each year.
The McDevitt laboratory is involved in active collaborations that target the development of what might be described as “pathology on a chip”. These efforts have led to the development of a membrane-based lab-on-a-chip sensor that is designed to capture cells from biological fluids or, in the case of oral cancer, non-invasive brush biopsy suspensions. The minimally invasive nature of the procedure allows examination of innocuous appearing lesions that do not warrant surgical biopsy, but may harbor high-risk of malignant transformation.
Oral cancer is uniquely suited to this type of biopsy due to the high accessibility within the oral cavity. Once captured, cells undergo assay-specific immunohistochemical labeling and epifluorescent imaging for known cancer markers. Intensity contouring using custom image processing macros identifies individual cells for measurement and correlation of multiple parameters. These activities have led to promising new diagnostic methods whereby a 15-minute chip-based pathology test has been developed with diagnostic accuracy comparable to the classical pathology exams that take three days to complete.
Bioterrorism Screening Tools
The development of rapid, reliable and cost-effective bio-agent detection systems currently represents one of the most important bio-terrorism priorities for our nation both for civilian and military sectors. Work in the McDevitt group has led to the development of a powerful bio-aerosol detection system suitable for the rapid and sensitive detection of bacillus spores in military settings.
Toxic Metal Screening Tools
"Single bead chromatographic techniques" are being developed that utilize protein subsets to chelate various metal ions. The methods can be used to quantify metal ions in solution and provide relative binding constants. To support these activities, protocols are being defined and refined that are suitable for the rapid screening of amino acid libraries to select for peptides that bind particular metals with a high specificity.
DNA-based Applications
The development of a chip-based sensor array composed of individually addressable agarose microbeads has been demonstrated for the rapid detection of DNA oligonucleotides. The "plug and play" approach allows for the simple incorporation of various biotinylated DNA capture probes into the bead-microreactors that are derivatized in each case with avidin docking sites. |
“Best of What's New Award” in Medical Device category , Popular Science. (December 2008).
Best Scientific Advances of the Year, Science Coalition . (1998).
Presidential Young Investigator Award, National Science Foundation. (1990).
