Ruiyu Li, Gregg Wildenberg, Kevin Boergens, Yingjie Yang, Kassandra Weber, Janek Rieger, Ashley Arcidiacono, Robert Klie, Narayanan Kasthuri, Sarah B King
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引用次数: 0
Abstract
Electron imaging of biological samples stained with heavy metals has enabled visualization of subcellular structures critical in chemical-, structural-, and neuro-biology. In particular, osmium tetroxide OsO4 has been widely adopted for selective lipid imaging. Despite the ubiquity of its use, the osmium speciation in lipid membranes and the process for contrast generation in electron microscopy (EM) have continued to be open questions, limiting efforts to improve staining protocols and therefore high-resolution nanoscale imaging of biological samples. Following our recent success using photoemission electron microscopy (PEEM) to image mouse brain tissues with synaptic resolution, we have used PEEM to determine the nanoscale electronic structure of Os-stained biological samples. Os(IV), in the form of OsO2, generates nanoaggregates in lipid membranes, leading to a strong spatial variation in the electronic structure and electron density of states. OsO2 has a metallic electronic structure that drastically increases the electron density of states near the Fermi level. Depositing metallic OsO2 in lipid membranes allows for strongly enhanced EM signals and conductivity of biological materials. The identification of the chemical species and understanding of the membrane contrast mechanism of Os-stained biological specimens provides a new opportunity for the development of staining protocols for high-resolution, high-contrast EM imaging.
期刊介绍:
ChemBioChem (Impact Factor 2018: 2.641) publishes important breakthroughs across all areas at the interface of chemistry and biology, including the fields of chemical biology, bioorganic chemistry, bioinorganic chemistry, synthetic biology, biocatalysis, bionanotechnology, and biomaterials. It is published on behalf of Chemistry Europe, an association of 16 European chemical societies, and supported by the Asian Chemical Editorial Society (ACES).