Development of a Time Resolved Fluorescence Spectroscopy System for Near Real-Time Clinical Diagnostic Applications

The design and development of a versatile time resolved fluorescence spectroscopy (TRFS) system capable of near real time data acquisition and processing for potential clinical diagnostic applications is reported. The TRFS apparatus is portable, versatile and compatible with the clinical environment. The main excitation source is a UV nitrogen laser with a nanosecond pulse width and the detection part consists of a dual grating spectrograph coupled with an MCP-PMT. The nitrogen laser also has a dye module attached to it, which enables broadband excitation of the sample. This setup allows rapid acquisition (250 ms for fluorescence decay at a wavelength) of time resolved fluorescence data with a high spectral (as low as 0.5 nm) and temporal (as low as 25 picoseconds) resolution. Alternatively, a state diode pumped pulsed laser can be used for excitation to improve data collection speed. The TRFS system is capable of measuring a broad range of fluorescence emission spectra (visible to near infra-red) and resolving a broad range of lifetimes (ranging from a few hundred picoseconds to several microseconds). The optical setup of the system is flexible permitting the connection of different light sources as well as optical fiber based probes for light delivery/collection depending on the need of the application. This permits the use of the TRFS apparatus in in vitro, ex vivo and in vivo applications. The system is fully automated for real-time data acquisition and processing, facilitating near-real time clinical diagnostic applications.