FluoPulse™ system is the first commercial, plug-and-play Fluorescence Lifetime Fiber Photometry (FLiP) system available on the market, designed for neuroscience. This system measures changes in a biosensor's fluorescence lifetime, and is an essential tool to monitor intracellular biochemical reactions in the brains of freely moving animals.  

The term "fluorescence lifetime" denotes the time lapse between the laser excitation and the release of fluorescence by the biosensor. Specially designed biosensors have unique lifetime distributions depending on whether they are in bound or unbound states. This disparity can be leveraged to study changes in neurophysiological states of key neural populations, including protein-protein interactions, changes in protein conformation, and the presence of neurotransmitters or other molecules of interest.

The FluoPulse™ system is designed to measure fluorescence lifetimes ranging between 1-10 ns and can resolve differences in lifetime of 10-20 ps. Thus, it is compatible with most biosensors designed for Fluorescence Lifetime Microscopy (FLIM) and Förster’s Resonance Energy Transfer (FRET), including FLIM-AKAR, GRAB-Ach3.0, etc. 

The FluoPulse™ system includes: 

The FluoPulse™ system uses a novel low-power Waveform Sampling method to measure the fluorescence lifetime in freely behaving animals. While traditional fluorescence lifetime measurement, Time-Correlated Single Photon Counting (TCSPC), is sensitive to background light that can skew experimental results, Waveform Sampling method is largely immune to background illumination interference. It is also possible to almost entirely cancel the effect of autofluorescence originating from fiber patch cords. Both immunities are crucial for in-vivo lifetime measurements, where fiber optic patch cords are required and ambient light cannot be eliminated. In addition, since Waveform Sampling collects many more photons per laser excitation, it provides a higher sampling rate and precision than the traditional method. 

Furthermore, fluorescence lifetime photometry measurements offer several advantages compared to classic, intensity-based photometry. Since lifetime is a molecular property, it is less susceptible to issues like photobleaching, expression levels, excitation power, and movement artifacts, which commonly pose challenges in intensity-based photometry. Consequently, fluorescence lifetime measures are more consistent between different animals and are exceptionally reliable for prolonged experimental paradigms spanning weeks and months, a critical timeframe for clinical studies. 

Thus, the FluoPulse™ system provides a state-of-the-art tool to measure fluorescence lifetime in a freely-moving animal, and opens avenues for discoveries in neuroscience and other fields where fluorescence lifetime offers valuable insights into the sample under investigation.