Imaging of flow pattern in micro flow channel using surface plasmon resonance

Abstract

We describe the visualization of the mixing and control of flow patterns in micro fluidic devices using a surface plasmon resonance (SPR) imaging sensor. We employed Kretschmann-type prism coupling SPR optics and an expanded laser diode light source via a single mode optical fibre. The reflected light was focused on a CCD camera. Two types of micro fluidic device were fabricated using photolithography and polymer imprinting a 2 mm wide, 100 µm high channel flow cell for the mixing and a slab channel device for flow control. We were able to observe mixing in the flow channel in real time with SPR imaging as the local refractive index change. Because the sensitivity of this system was limited within wavelength long distance from the gold surface, we could image the flow condition very near the channel wall. We also succeed in delivering the flow to a part of 4 × 4-array sensing area in a slab flow channel. These results will assist the development of integrated biosensors.