Methods for Atom Probe Tomography of Biological Materials

Atom Probe Tomography (APT) is a unique imaging and microanalysis technique enabling three-dimensional mapping of the chemical composition of materials at atomic-scale resolution- This method has found limited application with biological materials due to increased complexity of biosample specimen preparation, as well as certain intrinsic factors related to APT of these delicate samples- The goal of this project to address these technical issues, thereby expanding APT into more routine examination of biological materials at numerous R&D Facilities, including those operated by the Department of Energy- Existing barriers for applying APT to routine biological analysis include:asymmetricalfieldevaporationfrom highly heterogeneous materials; extremelyhighandpotentiallydestructiveelectrostaticallyinducedstresson the relatively fragile specimen tips during analysis; and the need to maintain the biological materials in a high vacuum and cryogenic environment- This project will attempt to remove these barriers using different technical approaches for biological APT analysis- The specimens produced will differ in physical structure from conventional atom-probe tips, and will be designed to reduce difficulties that have plagued previous biological APT investigations using standard methodology-