Microfluidic Biodetection P/F

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Background The ever-growing need for medical diagnostic systems in resource-limited settings is driving the development of microfluidic detection platforms. The advantages conferred by microfluidic platforms compared with their macro-scale counterparts include: lower analyte volumes, decreased reagent cost and rapid diffusion and adsorption times. Simple, standalone modes of detection for point-of-care diagnostics, particularly in resource-limited areas such as 2nd and 3rd world countries, is an area of high unmet need which microfluidic immunoassays can potentially fulfil; their lower analyte volumes greatly reduce the need for sterile collection materials and substantially decrease the production of biologically contaminated waste. The rapid diagnostic times characteristic of microfluidic detection assays allow patients to receive treatment upon their first clinical visit. Though fluorescent detection often improves the signal to noise ratio over visual detection schemes, it is restricted by a requirement for specialized light sources and detection filters. To make these systems useful around the world, they must be easily implemented and utilize readily available materials and resources. Similarly, despite the extreme sensitivity of electrochemical and spectroscopic methods of detection, their requirements for supplemental instrumentation and power sources make their implementation outside of a developed medical setting impossible. Technology A research team led by Christopher Bowman of the University of Colorado has developed a novel microfluidic detection platform that utilizes polymerization-based amplification (PBA) as a means for simple detection in microfluidic systems. This capillary flow device allows for multiple modes of detection requiring little or no supplemental instrumentation (visual observation, pressure monitoring, or by redirection of fluid flow). The rapid, equipment free nature of this approach is promising for potential deployment of point-of-care diagnostics in resource-limited settings. Central to PBA is a probe molecule which couples a polymerization initiator to the targeted biomaterial. Once the initiator is bound to the targeted species, monomer, and appropriate energy forms (chemical, light, etc.) are introduced to the sample, and polymerization amplification commences. An enzyme-mediated redox polymerization scheme has been employed, in which the binding of a glucose oxidase-avidin (GOx-Av) complex to a target, initiates a subsequent cascade of chemical reactions, resulting in a readily observable polymeric hydrogel. The GOx mediated PBA scheme results in a two-mode amplification system (enzymatic amplification AND polymerization amplification) which generates a macro-scale polymer from surface mediated reactions, capable of gelling monomer solutions in systems as large as standard 96 well plates, whereas non-GOx mediated PBA schemes result in only a nano or micro scale polymer film.