Opto-lipidomics of tissues
Lipid metabolism and signalling play pivotal functions in biology and disease development. Despite this, there is currently no optical technique available that can directly visualise the lipidome in tissues. In this study, we introduce opto-lipidomics, a new approach to optical molecular tissue imaging. We expand the capability of vibrational Raman spectroscopy to identify individual lipids in complex tissue matrices through correlation with desorption electrospray ionisation (DESI) - mass spectrometry imaging in an integrated instrument. A computational pipeline of inter-modality regression analysis is established to extract lipidomic information from optical vibrational spectra. Opto-lipidomic imaging of transient cerebral ischemia-reperfusion injury in a murine model of ischemic stroke demonstrates the visualisation and identification of lipids in disease with unprecedented molecular specificity using light. Furthermore, we deploy opto-lipidomics in a handheld fiber-optic Raman probe and demonstrate real-time classification of bulk brain tissues based on specific lipid abundances. Opto-lipidomics opens a host of opportunities to study lipid biomarkers for diagnostics, prognostics, and novel therapeutic targets.