Scalable substrate development for aqueous sample preparation for atom probe tomography.

Area of Science:

• Materials Science
• Nanotechnology
• Biophysics

Background:

• Preparing hydrated biological specimens for atom probe tomography (APT) is difficult, especially the focused ion beam (FIB) 'lift-out' step.
• Existing methods require specialized equipment and complex procedures, limiting broader application.

Purpose of the Study:

• Introduce novel substrate designs to simplify APT specimen preparation for biological samples.
• Reduce reliance on complex FIB procedures, making APT more accessible for hydrated biological specimens.

Main Methods:

• Developed two nanoporous alpha brass substrate designs: a laser-cut half-grid and a self-aligning 'crown' substrate.
• Utilized chemical and vacuum dealloying to create nanoporosity for enhanced liquid-substrate interface strength.
• Demonstrated substrate utility with example APT datasets.

Main Results:

• The new substrates allow FIB use primarily for sharpening, bypassing the difficult 'lift-out' step.
• Both designs are compatible with standard APT pucks and holders.
• Alpha brass proves to be a cost-effective and accessible material for these substrates.

Conclusions:

• The presented substrate designs offer a simplified and more robust method for preparing biological specimens for APT.
• These innovations have the potential to increase the adoption and application of APT in biological sciences.
• Further community adoption is encouraged through presented designs and data.