Fluorescence-guided optical photothermal infrared (O-PTIR) spectroscopy

We have developed a new multimodal microscope enabling “Fluorescence-Guided” Optical Photothermal Infrared (O-PTIR) spectroscopy. O-PTIR has proven itself a breakthrough in IR spectroscopy, providing IR spectroscopic analysis with spatial resolution ~20x better than traditional IR in a non-contact optical configuration. We have now coupled O-PTIR with fluorescence microscopy, a long established, cornerstone technique in life science research. The new fluorescence guided O-PTIR instrument allows: (1) a sample to be analyzed via fluorescence microscopy to map sample regions that are labeled one or more fluorophores; and (2) use fluorescence images to direct infrared spectroscopic analysis in the vicinity of the fluorescently labeled regions. We have used fluorescence guided O-PTIR to perform spectroscopic analysis of the protein secondary structure of fluorescently labeled amyloid plaques in mouse brain tissue, with the goal of providing insights in neurodegenerative disease research.