Creating internal conductivity in dry biological SEM samples by a simple vapour treatment

Area of Science:

• Materials Science
• Microscopy Techniques
• Surface Science

Background:

• Scanning electron microscopy (SEM) often requires metal coating for sample conductivity.
• Metal coating can obscure surface details and is challenging for some sample types.
• Proton conductivity in materials offers a potential alternative to traditional metal coating methods.

Purpose of the Study:

• To present a novel method for inducing proton conductivity in dry biological materials.
• To enable SEM analysis of uncoated biological samples.
• To enhance material contrast imaging and overcome charging issues in SEM.

Main Methods:

• Treatment of dry biological samples with hydrogen chloride gas or hydrochloric acid vapour.
• Short treatment duration (a few minutes) to achieve sufficient conductivity.
• Removal of excess hydrogen chloride using a vacuum desiccator before SEM examination.

Main Results:

• Successful generation of proton conductivity in dry biological materials.
• Samples treated with HCl gas/vapour exhibited sufficient conductivity for SEM analysis without metal coating.
• The method proved advantageous for material contrast imaging and improved conductivity on complex surfaces.

Conclusions:

• A simple and effective method for preparing biological samples for SEM by inducing proton conductivity.
• This technique expands the utility of SEM for analyzing uncoated biological specimens.
• The proton conductivity method offers a valuable alternative and complement to metal coating in SEM.