Non-freezing techniques of preparing biological specimens for electron microprobe X-ray microanalysis

Area of Science:

• Biochemistry
• Microscopy
• Cell Biology

Background:

• Conventional wet chemical techniques for electron microscopy (E.M.) are widely used for biological tissue preparation.
• These methods, including precipitation, often involve fluids that can compromise the in vivo chemical integrity of tissues.

Purpose of the Study:

• To review the artifacts introduced by wet chemical E.M. preparative techniques.
• To discuss the impact of these artifacts on the chemical integrity of biological tissues.
• To provide a realistic perspective on the biological applications of these methods.

Main Methods:

• Review of existing literature on wet chemical E.M. preparative techniques.
• Analysis of artifacts such as element loss, phase transformations, element redistribution, and introduction of extraneous elements.
• Discussion of biological applications and their limitations.

Main Results:

• Wet chemical methods can cause significant artifacts, including bulk element loss, phase transformations in mineralized tissues, redistribution of endogenous elements, and introduction of exogenous elements.
• Many studies using these methods focus on comparative chemistry rather than absolute in vivo composition.
• All available preparative techniques involve compromises.

Conclusions:

• No single general microprobe preparative technique is universally applicable.
• The choice of preparative technique should be tailored to the specific biological questions being addressed.
• Careful consideration of potential artifacts is essential for accurate interpretation of results.