Simultaneous self-referencing analyte determination in complex sample solutions using microfabricated flow structures (T-sensors~TM)

摘要

In microfluidic channels, fluids with viscosities similar to or higher than water and flowing at low velocities show laminar behavior. This allows the movement of different layers of fluid and particles next to each other in a channel without mixing other than by diffusion. A sample solution (e.g., whole blood), and a receptor solution (e.g., an indicator solution), and a reference solution ( a known analyte standard) are introduced in a common channel (T-Sensor~TM), and flow next to each other until they exit the structure. Smaller particles such as ions or small proteins diffuse rapidly across the fluid boundaries, whereas larger molecules diffuse more slowly. Large particles (e.g., blood cells) show no significant diffusion within the time the two flow streams are in contact. Two interface zones are formed between the fluid layers. The ratio of a property (e.g., fluorescence intensity) of the two interface zones is a function of the concentration of the analyte, and is largely free of cross-sensitivities to other sample componens and instrument aprameters. This device allows, for example, one-time or continuous monitoring of the concentration of analytes in microliters of whole blood without the use of membranes or prior removal of blood cells.