This proposal describes a request for funds to purchase a newly developed secondary ion mass spectrometer for 3-dimensional chemical imaging of biological cells and tissue. The instrument is based upon the use of a micro-focused ion beam consisting of energetic C60+ or Au3+ cluster ions to desorb biomolecules from a well-defined x,y coordinate into a novel TOF-TOF mass analyzer. Information about the 3rd dimension is obtained by erosion of the sample under high fluence ion bombardment conditions. This instrument is essential for the growing imaging mass spectrometry community because of its sophisticated cryogenic sample handling, greatly increased sensitivity and ms/ms capability. In addition, because of the unique design features, the instrument provides unprecedented lateral resolution of 300 nm for C60, and 50 nm for Au3, allowing sub-cellular imaging. These features will accelerate the research objectives of many NIH supported investigators interested in the cellular localization of drugs, metabolites and lipids. Representative projects include elucidation of de novo purine biosynthetic pathways in HeLa cells, assay of single vesicles in neurotransmitters, lipid biochemistry at model membranes, heart tissue and in liposomes. Five different collaborators from three Universities are involved in this effort, a situation made possible by the unique cryogenic sample handling associated with the mass spectrometer that allows frozen samples to be shipped across the country by air express. The instrument will initially reside in the PI's laboratory and be guided by an Oversight Committee. Financial support will come from the PI and from contributions from the collaborators. After the initial period of adjustment, the instrument will transition to an emerging Millennium Science Complex, a 265,000 square foot facility dedicated to biomaterials research. Although the initial number of collaborators is not large due to the complexity of each individual project and time limitations, it is anticipated that the results of this research will stimulate other groups to acquire this capability, bringing the technique to a wide swath of NIH investigators.
The 3-Dimensional Chemical Imager is a unique nanoscale tool for bioimaging that will provide basic information about mechanisms of neurotransmission, purine biosynthesis and lipid biochemistry. Results of these studies are proposed to impact a variety of disease states including learning memory and brain dysfunction, stroke, aortal valve defects, asthma and allergies, and the development of chemotherapeutic agents. The results will be overseen by a highly skilled technical staff that will be expanded over time to accommodate new users and new scientific endeavors. The environmental impact of mass spectrometry is relatively neutral with respect to most wet chemical or other instrumental methods. Samples are analyzed without significant chemical usage, and power consumption, associated mostly with vacuum pumps, is modest during and after spectrometer evacuation.
| Winograd, Nicholas (2013) Molecular Depth Profiling. Surf Interface Anal 45:3-8 |
| Lu, C; Wucher, A; Winograd, N (2011) Ionization effects in molecular depth profiling of trehalose films using buckminsterfullerene (C60) cluster ions. Surf Interface Anal 43: |
