Related Experiment Video
Updated: Aug 12, 2026

Visualization of miniSOG Tagged DNA Repair Proteins in Combination with Electron Spectroscopic Imaging (ESI)
Published on: September 24, 2015
A chemical mechanism for tissue staining by osmium tetroxide-ferrocyanide mixtures
Abstract:
The presence of Fe(CN)6(-4) provides sequential, one-electron reduction pathways for OSO4. An equilibrium is established containing OSO4, Fe(CN)6(-4), Fe(CN)6(-3), OSO2(OH)4(-4), and labile cyano-bridged OS-Fe species containing Os in nominal oxidation states of VIII, VII, and VI. These osmium complexes are chelated by appropriately placed donor atoms in the macromolecular tissue matrix, and chelation facilitates the reduction of osmium in situ to lower oxidation states (predominantly IV) that are relatively nonlabile. The greater reactivity and concentration of the Os(VII and VI) intermediates in this system leads to more Os deposition than OsO4 alone; the chelation is responsible for the immobilization of Os and the observed staining pattern in electron micrographs. Chemical data from model systems and electron micrographs of tissue are presented in support of this mechanism.
More Related Videos
09:21Serial Block-Face Scanning Electron Microscopy (SBF-SEM) of Biological Tissue Samples
Published on: March 26, 2021
09:51TD-DFT Guided Advanced E-Eye Sensing Technique for On-site Quantification of Fe, Cr, F, and As in the Environmental, Biological, and Food Samples
Published on: September 19, 2025
Related Concept Videos
Fixation and Sectioning
The simplest type of preparation is the wet mount, in which the specimen is placed in a drop of liquid on the slide. A liquid specimen can be directly deposited on the slide using a dropper. Solid specimens, such as skin scraping, can be placed on the slide before adding a drop of liquid to prepare the wet mount. Sometimes the liquid is simply water, but stains are often added...
Redox Titration: Overview
Complexometric Titration: Overview
Simple Staining Technique
Differential Staining Technique
Special Staining Techniques