With support from the Analytical and Surface Chemistry Program in the Division of Chemistry, Professor Marcel Utz and his group at the University of Virginia are working to combine the advantages of microfluidic devices and magnetic resonance spectroscopy (MRS). Similar to the more widely-known magnetic resonance imaging (MRI), MRS is a powerful method of chemical analysis which allows identification of chemical compounds as well as the detailed study of biological molecules such as proteins and nucleic acids. It is particularly well-suited to detect many different metabolites in biological systems simultaneously. Microfluidic devices are miniaturized chemical laboratories on a chip which allow precise control of very small amounts of liquids in complicated fluidic networks. They enable integration of laboratory procedures into a simple and expandable platform, often with huge improvements in cost, reliability, and throughput. The Utz group seeks to develop an efficient method to extract MRS spectra directly from samples inside microfluidic devices, without the need to transfer liquid from the chip to the MRS spectrometer. To achieve this, magnetic inductive coupling is being used to focus the sensitivity of the spectrometer onto specific fluidic chambers on the chip. This will enable new tools for research as well as medical diagnostics based on the simultaneous detection of a large number of metabolites.
The project is highly interdisciplinary, bringing together microfabrication, electrical engineering, chemistry, and spectroscopy. It provides an ideal learning and training environment for postdoctoral research associates as well as graduate and undergraduate students. It also provides summer research experiences for school students and teachers, familiarizing them with an exciting area of scientific inquiry.
Microfluidics is the chemical equivalent of microelectronics. Instead of an electrical circuit, a microfluidic chip integrates a chemical or biological reactor on a compact platform. Nuclear Magnetic Resonance (NMR) Spectroscopy is a close relative to Magnetic Resonance Imaging (MRI), which is widely used in medical diagnostics. Instead of providing images of the body, NMR spectroscopy provides a powerful tool for chemical analysis of biological samples, such as cells, blood serum, or urine. However, NMR spectroscopy, like MRI, relies on rather large equipment. Integrating it with microfluidic technology, therefore, presents important scientific and engineering challenges. Obtaining NMR spectra requires strong magnetic fields, which can only be produced by powerful superconducting magnets. These cannot be miniaturized, and it is therefore not possible to integrate an entire NMR spectrometer onto a microfluidic chip. Instead, we have taken the opposite approach: we make it convenient and efficient to insert the microfluidic chip into a conventional NMR spectrometer. Since NMR spectroscopy relies on radio signals, we have developed a new way to extract these signals from liquids on the chip wirelessly. This is important, because it allows to simply insert the chip and measure the spectrum, without any need to connect wires to it. We anticipate that the technology we developed will find broad use in scientific research, but also in the development of new drugs and in medical diagnostics.
