Native fluorescence spectroscopy on-a-chip
Native fluorescence spectroscopy is an interesting approach for pathogen detection since it is very sensitive and requires neither specific binding nor tagging of the analyte. Specificity needs can be met by a combination of multi-color excitation, collection of detailed spectral information and clever evaluation techniques are used. The presented approach combines these requirements into a compact solution which allows for on-chip native fluorescence spectroscopy. Our compact, low-cost pathogen detection platform combines a fluidic channel with a chip-size, distributed spectrometer that is optimized to record fluorescence spectra from moving analytes or particles as they traverse through the channel. Large-volume, continuous fluorescence excitation is achieved by incorporating the fluidic channel into an anti-resonance waveguide that accommodates either laser diodes or LEDs for multi-color excitation. Simultaneously monitoring total intensity and spectrally-resolved emission yields accurate spectra for particle discrimination. For the detection of native fluorescence of biological samples, like bacteria cells, it is favorable to use ultra violet light. A device capable for excitation with 266nm and detection in the ultraviolet part of the spectrum was built. Examples for single cells traversing the channel will be presented to demonstrate the sensitivity of the device.
Bassler, M. ; Kiesel, P. ; Schmidt, O. ; Johnson, N. M. ; Knollenberg, C. Native fluorescence spectroscopy on-a-chip. SPIE Optics East 2007; 2007 September 9-12; Boston, MA.