Confocal Raman microscope with scanning probe unit for correlative imaging

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For our research projects on biological tissues, cells, protein complexes as well as on sub-microscopic oxide particles, we apply for a high-resolution confocal Raman laser microscope with scanning probe and near field units for correlative imaging. Raman-spectroscopy excites a sample with a laser and analyzes the backsacttered light with a spectrometer. The spectrum contains specific information about the molecular structure of the sample. With a confocal Raman microscope, spectra can be imaged with a spatial resolution of ca. 300 nm, which allows for visualization and identification of major cell organelles – without histological staining techniques (label free imaging). In correlated Raman-Scanning-Probe-Mikroscopy, a scanning probe tip is used to additional collect information about topography, intermolecular forces, electric and magnetic fieldsund magnetische fields, which when superimposed on the molecular signal from Raman-spectra produces comprehensive picture about the physico-chemical properties of a sample. With a scanning near field probe (SNOM), spectra can be extracted from the near-surface region of a sample with resolution below 100 nm.The microscope is intended to strengthen various projects that are currently funded at the University of Oldenburg and to allow preliminary analysis for new research projects. In particular, we are planning on using the microscope for a number of projects within the DFG funded collaborative research center SFB1372 (funded since 2019) with the aim to identify and characterize putative magnetic sensory cells in animal tissues. The magnetically active sensory structures defy identification by conventional microscopy techniques, which is why we here envisage a high resolution correlative Raman-scanning probe-microscpy approach. We will further use the microscope to for microbiological topics, such as organelle structure of single-celled algae, quantitation of metabolic heterogeneity in isoclonal populations of bacteria, as well as for the characterization of redoxaktive proteins in the cell membrane of sulfate-reducing bacteria taking advantage of resonant Raman transitions in Fe-S centers. The microscope will also be used in inorganic chemistry for the characterisation of photocatalytic and electrocatalytic materials materials (transition metal-oxide particles).