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Raman microspectroscopy provides for high-resolution non-invasive molecular analysis of biological samples and has a breakthrough potential for dissection of cellular molecular composition at a single organelle level. However, the potential of Raman microspectroscopy can be fully realized only when novel types of molecular probes distinguishable in the Raman spectroscopy modality are developed for labeling of specific cellular domains to guide spectrochemical spatial imaging. Here we report on the design of a next generation Raman probe, based on BlackBerry Quencher 650 compound, which provides unprecedentedly high signal intensity through the Resonance Raman (RR) enhancement mechanism. Remarkably, RR enhancement occurs with low-toxic red light, which is close to maximum transparency in the biological optical window. The utility of proposed RR probes was validated for targeting lysosomes in live cultured cells, which enabled identification and subsequent monitoring of dynamic changes in this organelle by Raman imaging.

Detailed studies of lipids in biological systems including their role in cellular structure, metabolism and disease development, comprise an increasingly prominent discipline called lipidomics. However, the conventional lipidomics tools, such as mass spectrometry, cannot investigate lipidomes until they are extracted, and thus cannot be used neither for probing the lipids distribution, nor for studying in live cells. Furthermore, conventional techniques rely on the lipid extraction from relatively large samples, which averages the data across the cellular populations and masks essential cell-to-cell variations. Further advancement of the discipline of lipidomics critically depends on the capability of high-resolution lipid profiling in live cells and, potentially, in single organelles. Here we report micro-Raman assay designed for single organelle lipidomics. We demonstrate how Raman microscopy can be used to measure the local intracellular biochemical composition and lipidome hallmarks -lipids concentration and unsaturation level, cis/trans isomers ratio, as well sphingolipids and cholesterol levels in live cells, with a submicron resolution, which is sufficient for profiling of subcellular structures. These lipidome data were generated by a newly developed Biomolecular Component Analysis software, which provides a Correspondence should be addressed to A.N.K.

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Gunshot residue (GSR) is potentially key evidence during a criminal investigation of a shooting accident. Current standardized forensic science methods target the detection of inorganic GSR (IGSR). In this proof-of-concept study, a new two-step method for the detection and identification of organic GSR (OGSR) is proposed. This method utilizes highly sensitive fluorescence hyperspectral imaging of a sample area to detect potential GSR particles, followed by confirmatory identification of the detected particles using Raman microspectroscopy. In this study, two different GSR samples on adhesive tape substrates were created. One sample was made by manually placing a known amount of OGSR particles onto an adhesive tape substrate. The second sample mimicked a real crime scene situation and had an unknown number of GSR particles mounted onto an adhesive tape substrate using a most common tape-lifting procedure for the recovery of GSR from the skin of a suspect and other surfaces. These two samples were subjected to the developed twostep analysis method. It was found that this method was accurately able to detect and identify all OGSR particles. Representative spectra of OGSR particles showed characteristic Raman peaks at 850 cm −1 , 1287 cm −1 , and 2970 cm −1 . This methodology offers a promising means to meet current needs within the framework of GSR analysis by providing a way to accurately detect and identify OGSR.