Time-Resolved Emission Imaging Microscopy with long-lived Pt(II) complexes: a new approach to autofluorescence-free imaging of tissues

The problems of background autofluorescence are considerable and widespread in many avenues of complex cell and tissue research. This includes a diverse range of endpoints where fluorescence imaging is an absolute requirement, and examples include clinical diagnostics, medical research and the fundamental study of cell and tissue biology. Our short proposal aims to solve these problems by use of a technique called time-resolved emission imaging (TREM) - a method realised by us in 2008. The potential value of TREM has only just become a practical reality due to the recent development of very stable and long-lived Pt(II) luminescent complexes (also developed by us). However, the true exploitable value of these molecules is one of versatility by conjugation to selective high affinity antibodies for the multitude of possible immunolabelling targets. This will have a major technical advantage for imaging complex tissues traditionally hampered by autofluorescence, by enabling proteins and cells to be resolved in isolation without fluorescent interference that would otherwise prevent detailed imaging.

This 12-month feasibility study will exploit the remarkably photostable properties of a family of brightly emissive platinum (II) complexes for luminescent imaging and mapping of tissues by time-resolved emission microscopy (TREM) - a method realised by us in 2008. The key biological problem we propose to solve is the removal of autofluorescence arising in complex biological tissues that frequently prevents or interferes with the visualisation of positively immunolabelled structures when conducting immunofluorescence microscopy. In order to achieve this goal, highly emissive Pt(II) complexes (also developed by us in parallel) will be conjugated to secondary antibodies and used in conjunction with primary antibodies for immunolabelling positively labelled verses background autofluorescent structures by TREM. We have set an ambitious 1-year time frame to develop and underpin the potential breadth of applications that this technology holds for fluorescence imaging; with a long-term aim that TREM will be complementary, and as widespread as confocal microscopy.