Non-radioactive Uranyl Acetate Substitutes for Biological Electron Microscopy: Why Lanthanide... (SC21)

Course overview

Contrast staining in biological electron microscopy (EM) is typically achieved using en bloc and post-section staining with uranyl acetate (Uac), a toxic reagent that poses a significant health hazard due to mild radioactivity. Increasingly restrictive regulations, radiation monitoring, storage and the financial cost are becoming barriers to using Uac routinely in EM labs, giving rise to a need for non-radioactive, less expensive substitutes with equivalent contrast results. Gadolinium triacetate (GA), a non-radioactive, low hazard substitute for Uac, and other reported lanthanides will be discussed with examples of combinatorial en bloc and post-grid staining as compared to Uac staining for scanning and transmission EM. By using GA for routine EM staining, it is noted that the electron density for contrasting cellular membranes, organelles, and extracellular matrices were equivalent to Uac staining without the accumulation of precipitate artifact. Furthermore, GA costs less than Uac, does not require special handling, monitoring, storage, or radioactive waste disposal.