The research in the Emergent Magnetic and Atomic Structures Group is aimed at determining the nature of macromolecule-mediated nanoparticle formation by utilizing advanced electron microscopy techniques.
Electron microscopy is the primary analytical tool when working with materials at the nanometer to sub-angstrom length scales. Nanometer-sized specimens are normally prepared by placing a drop of nanoparticles suspension on a suitable electron microscopy (EM) grid and allowing it to dry to accommodate the high vacuum environment inside the TEM, required for electron imaging. Unfortunately, solvent evaporation can induce unwanted aggregation of suspended nanoparticles, making analysis of such systems difficult due to the presence of a large number of randomly oriented, overlapping features of interest.
Using various templating agents, it is possible to form nanoparticles directly on the electron-transparent silicon nitride window membranes. Such a controlled synthesis drastically reduces the overall number of the nanoparticles and their solvent-induced agglomeration. We are working on the surface deposition of biomacromolecules and screening a variety of linker molecules for their immobilization on the window surface. We will use x-ray photoelectron spectroscopy, wavelength dispersion spectroscopy, and surface IR microscopy to evaluate the linker efficiency and will establish a combinatorial approach to the surface patterning. Optimal linker molecules will be used for creating the surface libraries of templating macromolecules.
Mentor: Tanya Prozorov, Assistant Scientist III, Ames Laboratory