Research

Lab-on-a-Chip Integration Theme: The Great Challenge

Despite the remarkable advances in the development of miniaturized sensing and analytical components for use in a variety of biomedical and clinical applications, the ability to assemble and interface individual components in order to achieve a high level of integration in complete working systems continues to pose daunting challenges for the scientific community as a whole. The McDevitt laboratory has developed previously a number of miniaturized sensor concepts and methodologies that are suitable for a variety of important application areas such as clinical, environmental, bioterrorism, humanitarian and saliva-based diagnostic tools.

Over the past five decades, the microelectronics industry has sustained tremendous growth and has become what is arguably the most dominant industrial sector for our society. The electronics industry has spawned compounded annual growth of over 50% over this extended time period. This industry has touched almost every aspect of our modern lives through the development of personal computers, portable communication devices, various consumer electronics, navigation tools, imaging devices, etc. The availability of powerful microfabrication tools based on photolithographic methods that can be used to process these devices in highly parallel manner has led to this explosive growth.

Recently, it has become clear that the electronic industry will face new and significant challenges as component device feature sizes shrink into the nanometer size regime. However, with the challenge here comes the opportunity to develop a number of fascinating new sensors and devices using nano meter sized building blocks. The ultimate applications to be derived from such interdisciplinary efforts are likely to occur for the sectors in the life sciences and in the areas related to the health industries. Challenges with spiraling health care costs associated with cardiovascular disease, cancer, and diabetes, the global HIV crisis, and environmental and homeland defense areas all provide strong motivation for the creation of a bridge between microelectronics, nano-engineering and the health sciences.

Despite the remarkable advances in the development of miniaturized sensing and analytical components for use in a variety of biomedical and clinical applications, the ability to assemble and interface individual components in order to achieve a high level of integration in complete working systems continues to pose daunting challenges for the scientific community as a whole.

Lessons learned from the microelectronics and computer-software industries provide inspiration for what may be gained from the marriage of microelectronics and in vitro diagnostics areas. Indeed, there are some interesting parallels between the current state of medical devices, in particular, in vitro diagnostics, and the evolution of software and microelectronics industries. While medical tests have traditionally been completed in central laboratories that are filled with specialized equipment and trained technicians, there is currently a trend to complete more and more tests using portable instrumentation. Indeed, the point of care medical device area represents now the fastest growing sector of in vitro diagnostics. At some level, this evolution of medical diagnostic testing follows the same pathway the computer industry took where initial work stations were dedicated to single tasks. Over time, the computer became programmable and portable to the point where “personal computers” have evolved with high degree of task flexibility. Clearly, the availability of portable medical devices that could be tailored for “personal medical exams” using noninvasive diagnostic fluids such as saliva would have a profound influence on the way medical testing is practiced.

The ability to assemble and interface individual components in order to achieve a high level of integration in complete diagnostic devices continues to pose a daunting challenge for the scientific community as a whole. Even more difficult is the prospect of creating a modular standard “assay operating system” that can be adapted in a simple and rapid manner to new assays. Towards this goal, the McDevitt laboratory has developed previously a number of miniaturized sensor concepts and methodologies that are suitable for a variety of important application areas. Here, a system based on a micro-bead array wherein micro-etched pits within a silicon wafer are populated with a variety of chemically sensitized bead “micro-reactors." Created with many of the same microfabrication methods popularized by the electronics industry, such flexible sensor systems can be described as “chemical processing units." Developed initially as an “electronic taste chip” (ETC) system, this LOC-based sensor platform has been adapted now for a broad range of analyte classes including pH, electrolytes, metal cations, sugars, biological co-factors, toxins, proteins, antibodies, and oligonucleotides.