ITS 2004 Summer Visiting Fellows Program

August 13, 2004 - ITS Mini-symposia on Bio-imaging at Argonne National Laboratory

On August 13, 2004 the Institute hosted three speakers at Argonne National Laboratory: Prof. Gabor Forgacs from the University of Missouri-Columbia, Prof. Masaru Ken Kuno from the University of Notre Dame, and Prof. Rusty Lansford from the Beckman Institute, California Institute of Technology. The mini-symposia was of large interest, among the audience were 2003 Physics Noble Laureat Prof. Alexei Abricosov and other distinguished Argonne scientists.

ITS SYMPOSIA ON BIO-IMAGING
ARGONNE NATIONAL LABORATORY, August 13, 2004

Useful biomechanics from the subcellular to the organismal levels
Prof. Gabor Forgacs ~ University of Missouri - Columbia
Abstract: I will overview our lab's activity in the field of biomechanics with emphasis on those aspects that are biologically useful. At the subcellular level, biomechanics is used to improve on the yield of embryo cryopreservation. At the cellular scale, biomechanics is employed to quantify and thus better understand how white blood cells or tumor cells may initiate exiting the circulatory system, respectively, during inflammatory response and metastasis. At the supercellular or tissue level we rely on biomechanics to optimize our efforts in studies on morphogenetic processes, in particular “organ printing”, an evolving technology to construct 3D functional organ modules of desired shape using methods of rapid prototyping. In these endeavors we use magnetic tweezers, atomic force microscopy-based force micromanipulators, specifically designed bioprinters and other special purpose, usually in-house built instrumentation.


Dynamic Visualization of Embryogenesis
Prof. Rusty Langsford ~ Beckman Institute, California Institute of Technology
Abstract: My research aims to dynamically visualize and characterize avian embryonic development at sub-cellular resolution. My primary focus is determining how the brain and heart form and develop. Instead of labeling and following small numbers of cells at a time, I am trying to optically record all or nearly all the cells within a developing embryo simultaneously. I will place fluorescent tags within all avian embryonic cells using GFP-expressing retroviruses. Cell and tissue movements in the developing embryos are recorded using multispectral, time-lapse fluorescent microscopy in 3D. The recorded data is then analyzed using computers running sophisticated cell-tracking and color discrimination software capable of distinguishing the subtle movements that thousands of individual cells make and identifying a handful of genes that these cells express. The gene expression and cell migration data collected using laser microscopes is then integrated within MRI collected datasets in order to understand the complex informational interactions that are occurring during development within the spatial and temporal context of the maturing embryo.

Solution-based straight and branched semiconductor nanowires
Prof. Masaru K. Kuno ~ University of Notre Dame
Abstract: Long standing interest in understanding and ultimately controlling crystal growth has recently materialized as studies into new routes for making high quality metal and semiconductor nanocrystals (NC), nanorods (NRs), nanowires (NWs), as well as other higher order nanostructures. The discovery that metal NCs have catalytic properties for promoting asymmetric crystal growth has motivated studies into making 1D semiconductor NWs. Recent investigations have led to the development of synthetic techniques that include variations of traditional vapor-liquid-solid growth, wherein chemically synthesized or laser ablated metal NCs are used as catalyst particles. Such routes take advantage of advances in NC syntheses to overcome intrinsic droplet size limitations, ultimately allowing one to create previously unattainable, narrow diameter NWs. Other approaches include complete solution phase analogues of VLS growth such as solution-liquid-solid (SLS) growth and supercritical-fluid-solid (SFLS) growth.
Here the solution phase synthesis of narrow diameter (< 10 nm) straight and branched CdSe NWs is described. Crystalline NWs with lengths between 1-10 microns are obtained using a seeded solution approach, whereby NW growth is initiated using Au/Bi core/shell NCs. Such wires may exhibit unique quantum confinement effects given that the bulk exciton Bohr radius of CdSe is 5.6 nm. Manipulating the reaction conditions allows one to transition from straight to branched nanowires yielding, tripod, v-shaped, and y-shaped NWs. Further variations in the preparation lead to higher order NWs that exhibit multiple branching points. In all cases, the presence of surface binding surfactants yields soluble straight and branched NWs opening up intriguing opportunities for future surface modifications and/or surface functionalization chemistries. Such branched wires also provide the distinct possibility of studying not only size dependent optical and electrical properties of NWs but also their shape dependent properties as well.