Collection, focusing, and metering of biomolecules using addressable microelectrode arrays for portable low-power bioanalysis

Texas A&M Engineering Experiment Station, College Station TX

Investigators

Abstract

Abstract: Advances in microfluidic technology have enabled increasingly sophisticated biosensing and bioassay operations to be conducted at the microscale, many of these applications employ such small amounts of DNA that it must first be pre-concentrated to a detectable level. Often the sample contains multiple components or is unknown, making it difficult to employ techniques like polymerase chain reaction (PCR) amplification to increase the concentration level. Efficient strategies for precisely handling minute quantities of biomolecules in microchannel geometries are critically needed, however it has proven challenging to achieve simultaneous concentration, focusing, and metering with current-generation technology. This research program will address these issues by exploring advanced microfluidic systems incorporating arrays of on-chip electrodes to digitally collect and meter DNA and other charged biomolecules in precise and controllable increments. This technique transports charged biomolecules between active electrodes upon application of a small potential (~1 V), and is capable of achieving orders of magnitude concentration increases within a small device footprint suitable for portable operation (a single AA battery may deliver sufficient power to perform multiple concentration and metering operations). The collected samples are highly focused, with sample zone size and shape defined solely by electrode geometry. The results of these fundamental studies will also be applied to explore entirely new first-of-their-kind applications for this technology including (i) coupling the capture process with a superimposed hydrodynamic flow to concentrate and re-suspend a DNA sample in a new buffer environment suitable for subsequent reactions or analysis, (ii) harnessing the electrode capture process to collect DNA in free solution followed by hydrodynamic injection of a gel sieving matrix directly over the collected DNA to perform subsequent electrophoretic separation, and (iii) capture and focusing of protein samples. These novel applications will address the compelling economic incentives for developing advanced DNA-based assay technologies that will be key components in next-generation genomic analysis systems. In addition to the commercial impact associated with making genomic analysis technology more affordable, this technology will greatly enhance education in emerging multidisciplinary areas of the Chemical Engineering discipline through integration with the PIs efforts to develop new educational experiences for undergraduates at the interface between the physical, chemical, and life sciences. The PI will also introduce a regular series of debates involving undergraduates, graduate students, and faculty to stimulate interest in the societal impact of bio- and nanotechnology issues while improving communication skills and providing a common experience that can be shared by the entire department. Students involved in this project will gain hands-on experience in areas at the frontiers of the Chemical Engineering discipline, and society will benefit through the development of new genomic analysis technology for improved health care.