A new family of chemical labels with lifetimes several fold greater than traditional fluorophores are being researched in to and used in the development of a new method for biological imaging – time resolved emission imaging microscopy (TREM).
A fundamental understanding of the mechanisms and processes that control biological systems relies on technological achievements in real-time imaging. A very common imaging modality for studying biological systems is fluorescence microscopy, which benefits from a high spatial and temporal resolution in conjunction with acute sensitivity
A major advantage of fluorescence microscopy is an ability to span magnitudes of length-scale, enabling scientists to visualise whole organisms at one end of the scale right down to single molecule interactions at the other.
Recent work between the Universities of Sheffield and Durham, and the Rutherford Appleton Laboratory in Oxford, has seen the development of a novel class of luminescent Pt(II) labels for biological imaging. The luminescent lifetimes of these molecules are measured in microseconds rather than nanoseconds.
Development of the Pt(II) complexes has enabled the realisation of TREM, which exploits the long lifetime of the labels. TREM is similar to fluorescence lifetime imaging microscopy (FLIM) but uses much longer timescales of hundreds of nanoseconds to microseconds.
The advantage is that longer timescales offer improved discrimination through much larger changes in lifetime and allow time-gated experiments to distinguish from short-lived autofluorescence. TREM does not need fast excitation or detection methods, indeed it can be performed with nanosecond lasers and slower gated detectors.