The detection of very dilute bioparticles using lab-on-a-chip technology presents a currently unsolved problem. The applicants will design and demonstrate a microfluidic concentrator device that uses an isothermal rapid evaporation process for the concentration of bacteria, viruses, and proteins. The biosample can be maintained at room temperature or at a somewhat elevated temperature throughout the concentration process, while the only constituents removed are the volatiles (i.e., fluids that have a high vapor pressure, primarily water). The process takes a sample volume of up to 20 milliliters and rapidly concentrates it to a final volume of 100 microliters. The disposable device will have dimensions of approximately 5 cm x 6 cm x 0.7 cm, which includes the sample reservoir. The concentrator is particularly powerful because it is generically applicable, does not depend on the characteristics of the dissolved or dispersed particles to be concentrated, and requires little or no external instrumentation. Further, the applicants will design and evaluate a chemical lysing structure based on exposure of a focused ribbon of bioparticles to diffusing lysing agents contained in a sheath stream. The lysing structure can be integrated with the evaporative concentrator as well as with other sample preparation subcircuits. All devices will be implemented as laser-microfabricated laminated microfluidic disposables. A successful Phase I will provide a generically applicable evaporative concentrator unit. After successful completion of Phase I, MicroPlumbers will apply for Phase II funding for the development of an integrated prototype comprising the evaporative concentrator, debris removal unit, lysing system, and an interface to a detection technology compatible with microfluidic devices.
