Associate Faculty, Biodesign Center for Applied Structural Discovery
Research Professor, Physics Department
Professor Weierstall conducts multidisciplinary research over a wide range of scientific topics, ranging from condensed matter physics to biophysics. His research is predominantly experimental and is based on the use of electron and X-ray beams for imaging, spectroscopy and diffraction. He is interested in developing methods for structural analysis of bio-molecules. In an ongoing collaboration with Lawrence Berkeley National Laboratory (LBNL), a project is under way to obtain high-resolution images from X-ray diffraction patterns by iterative phase reconstruction.
Similar efforts at ASU use electron diffraction patterns obtained in Transmission Electron Microscopes. The most recent project focuses on the development of a new technique to solve the structure of proteins, which cannot be crystallized. Proteins will be injected into the X-ray free electron laser beam at the Linac Coherent Light Source (LCLS) in Stanford. The short, extremely bright X-ray pulse generates a diffraction pattern before the molecule is destroyed. This diffraction pattern can be phased to generate an image of the molecule ("lensless imaging").
Preliminary experiments injecting single cells into the first European X-ray laser FLASH showed the feasibility of this approach. A similar approach using a continuous X-ray beam at LBNL has produced the first powder diffraction data of membrane proteins. The droplet injectors used for both projects are being developed at ASU.
This NSF funded project is a collaboration with Profs. Doak, Spence, Fromme, Schmidt at ASU and researchers at LBNL, Lawrence Livermore National Laboratory (LLNL) and DESY (Germany). Previous projects at ASU: (1) Development of the Scanning Tunneling Atom Probe, which integrates a time-of-flight spectrometer with a Scanning Tunneling Microscope (STM) for chemical analysis. (2) Development of an electron diffraction camera for quantitative surface analysis in convergent beam mode. (3) Development of a helium cooled STM. (4) Low energy electron holography and point projection microscopy for bio-molecule imaging. (5) Development of an algorithm, which uses diffractive imaging methods to help solve the phase problem in electron crystallography from organic monolayers.