Fluorescent detection is one of the most widely used techniques for biochemical analysis and medical diagnostics. Tagging of DNA and protein with fluorescent dyes allows them to be detected with high sensitivity. Changes in intrinsic or attached probe fluorescence can be indicative of structural transformations. In recent years, significant research has been done in the miniaturization of biochemical instrumentation, leading to the development of microfluidic, “lab-on-a-chip” technologies. With respect to fluorescent detectors, the efforts have focused on solid-state sources such as light emitting diodes (LEDs) and solid-state lasers. However, these sources are not made with the same fabrication techniques common to microfluidic systems. In addition, numerous applications require short wavelength ultraviolet light, which is not readily generated by these sources.
Researchers at the University of Michigan have developed a novel design for an optical source and system that integrate this source for excitation and detection of fluorescence. The source operates by igniting a pulsed discharge between a metal anode and a microfluidic cathode filled with an aqueous solution of a suitable salt. Characteristic transitions of cations, which are sputtered into the glow area, provide strong emissions in visible and ultraviolet spectral ranges. Undesirable wavelengths are blocked out by integrated optical filters. The device not only provides a source of illumination with desired wavelengths, but can also be easily integrated with micro-total analysis systems such as a microfluidic device.
Applications and Advantages
- Light source for microfluidic applications
- Specifically designed for microfluidic application
- Easily integrated into microfluidic devices
- Able to provide short UV illumination