BioNanotechnology Seminar Series - Fall 2013

Gold Nanorods in the Extracellular Matrix and their Effect of Cancer Cell Migration
Elissa M. Grzincic, Chemistry

Tuesday, December 3, 2013
1000 MNTL, 12:00 - 12:30 PM

Abstract: Gold nanorods are being studied within biological systems for applications such as drug delivery, imaging, detection and  photothermal therapy. These nanoparticles are easily modified in terms of size, shape and surface ligands in order to subsequently modify their unique optical properties and how they interact with cells. Many studies have investigated interactions between gold nanorods and cells, but it is important to know  more  about  how  these  nanoparticles  may  affect  cellular  interactions  with  their  immediate   environment. Furthermore, 3D environments may be better suited for mimicking in vivo environments used to study cellular functions, rather than traditional 2D environments.

Using nested collagen gel matrices as models to mimic gold nanorods in the extracellular matrix (ECM) of human cancer cells, the effect of the nanorods on cell migration was investigated. It was observed that gold nanorods in the ECM induce changes in spontaneous cell migration. It is hypothesized that the change in cell  behavior  upon  addition  of  gold  nanorods to the outer collagen gel could be due to differences in mechanical  properties,  the  creation  of  biochemical  gradients,  or  a  combination  of  both.  To begin investigating  the  mechanism  behind  the  changes,  mechanical properties of gels were measured with rheology,  images  were  collected  with  confocal fluorescence and reflectance microscopy, and matrix metalloproteinase levels were measured by gelatin zymography.

 

Microfabricated Biological Machines for Sensing and Locomotion
Ritu Raman, Mechanical Science and Engineering

Tuesday, December 3, 2013
1000 MNTL, 12:30 - 1:00 PM

Abstract: The advent of 3D printing additive manufacturing technologies has enabled the rapid fabrication of complex structures. Concurrently, advances in the field of tissue engineering have created complex biological substitutes for native tissue and organs. A synthesis of principles from these two fields brings about a new discipline: forward engineering of microfabricated biological machines and systems capable of complex functional behaviors. Such machines can be tailored to a myriad array of sensing and actuation tasks in vitro and in vivo.

 

The complexities of targeting nanoparticles into solid tumors
Dr. Warren Chan, Professor, Institute of Biomaterials and Biomedical Engineering, University of Toronto

Tuesday, November 5, 2013
1000 MNTL, 12:00 - 1:00 PM

Abstract: Nanoparticles of different sizes, shapes and material properties have many applications in biomedical imaging, clinical diagnostics and therapeutics. Strategies that can reproducibly prepare colloidal nano-particles of a wide range of geometries with a tight size distribution have been achieved and unique size and shape dependent optical, magnetic, electrical, and biological properties have been discovered. A broad of range of applications of nanoparticles have been demonstrated. In spite of what has been achieved so far, a complete understanding of how cells and animals interact with nanoparticles of well-defined sizes remains poorly understood. This has led to the inability to rationally design nano-particles for cancer applications or has led to the inability to establish a definitive conclusion on the toxicity of nanomaterials. In this presentation, the properties of nanomaterials and challenges associated with using them for cancer targeting will be discussed, and finally, there will be a discussion on how microfluidics and DNA assembly techniques can be exploited to address the current limitations of nanomedicine.

Bio: Dr. Chan is currently a Full Professor in the Institute of Biomaterials and Biomedical Engineering at the University of Toronto. He also holds the Canadian Research Chair in Bionanotechnology and is affiliated with the Department of Materials Science and Engineering, the Terrence Donnelly Center for Cellular and Biomolecular Research Chemistry, Chemistry and Chemical Engineering. His research interest is in the development of nano- and microtechnology for cancer and infectious disease diagnosis. He has received the NSERC E.W. R. Memorial Stecie Fellowship (Canada), BF Goodrich Young Inventors Award, Lord Rank Prize Fund award in Optoelectronics (England), and Dennis Gabor Award (Hungary). Dr. Chan received his B.S. degree from the University of Illinois in 1996 and Ph.D. degree from Indiana University in 2001. He did his post-doctoral training at the University of California (San Diego). He will be starting as an Associate Editor of ACS Nano and is currently on the Editorial Advisory Board of the journals Nanomedicine, Advanced Healthcare Materials, and Journal of the Automatic Laboratory Automation.

 

Perspectives on Working at a DOE National Laboratory
Dr. Harry Radousky, Visiting Scientist at the Illinois Applied Research Institute
Staff Scientist, Lawrence Livermore National Laboratory

Tuesday, October 22, 2013
1000 MNTL, 12:00 - 1:00 PM

Bio: Dr. Harry Radousky is a Visiting Scientist at the Illinois Applied Research Institute from Lawrence Livermore National Laboratory, where he is a staff scientist. Dr. Radousky received his Ph.D. in Physics from the University of Illinois, Chicago and performed his thesis research as an Educational Fellow at Argonne National Laboratory. He joined the Lawrence Livermore National Laboratory in 1982 and has published over 100 papers in the areas of magnetism, superconductivity, high pressure physics, optical materials, energy harvesting and nanomaterials. Administratively at LLNL, Dr. Radousky has served as Deputy Director for the University Relations Program (URP); Division Leader for Recruiting Programs; and Program Director for the Visiting Scientists Program. These included concurrent appointments as the founding Director of LLNL's Materials Research Institute from 1997-2000, Director of Lab Collaborations at UCOP from 2001-2002, Scientific Editor for Science & Technology Review (S&TR) from 2005-2007, Program Manager of the Lawrence Fellows Post-Doctoral Program from 1997-2009, and the Program Manager of the Lawrence Scholar Graduate Student Program from 2003-2009. Dr. Radousky has also spent time on assignment at Lawrence Berkeley National Lab (LBNL) in their Technology Transfer Department. He holds an adjunct appointment as Professor of Physics at the University of California, Davis, and teaches a freshman seminar on the Physics of Baseball. Dr. Radousky is a Fellow of the American Physical Society

 

Poly(iohexol) Nanoparticles As Contrast Agents for In Vivo X-ray Computed Tomography Imaging
Qian Yin, Materials Science and Engineering

Tuesday, October 8, 2013
1000 MNTL, 12:00 - 12:30 PM

Abstract: X-ray computed tomography (CT) is one of the most frequently used clinical diagnostic tools. Current clinically used CT contrast agents are largely based on iodinated small molecules. When used in vivo, however, they always get eliminated from body rapidly, leading to a very narrow time window for CT imaging and failing to provide sufficient contrast for the regions of interest. In this presentation, biocompatible poly(iohexol) nanoparticles, prepared through cross-linking of iohexol and hexamethylene diisocyanate followed by co-precipitation of the resulting cross-linked polymer with mPEG-polylactide, were utilized as contrast agents for in vivo CT imaging. Compared to small-molecule contrast agents, poly(iohexol) nanoparticles exhibited substantially protracted retention within the tumor bed and a 36-fold increase in CT contrast 4 h post injection, which makes it possible to acquire CT images with improved diagnosis accuracy over a broad time frame without multiple administrations.

 

Suspension-based Measurements in Surface-Enhanced Raman Spectroscopy
Brent DeVetter, Electrical and Computer Engineering

Tuesday, October 8, 2013
1000 MNTL, 12:30 - 1:00 PM

Abstract: We have investigated the rational design of highly sensitive and chemically specific surface-enhanced Raman scattering (SERS) nanoprobes for biological sensing applications. We find that consideration of the optical scattering and absorption properties of nanoprobes in conjunction with their SERS properties is essential for maximizing signal in three-dimensional environments. Gold nanorods with tunable optical properties were synthesized and surface modified with biologically compatible polyelectrolytes. Raman analytes were electrostatically bound between layers of polyelectrolyte. Our results indicate that gold nanorods with localized surface plasmon resonances that are blue-shifted from the excitation wavelength achieve maximal signal intensity. Future work will involve embedding nanoprobes into tissue phantoms to further investigate the properties of SERS nanoprobes in turbid media as we move towards in vivo sensing.

 

Facile and efficient preparation of anisotropic DNA-functionalized gold nanoparticles and their regioselective assembly
Li Huey Tan, Chemistry

Tuesday, September 24, 2013
1000 MNTL, 12:00 - 12:30 PM

Abstract: Anisotropic nanoparticles hold great potential for assembly of nanomaterials with unique structures and properties. However, most reported anisotropic nanoparticles are either difficult to prepare, have a low yield, or difficult to functionalize. In this presentation a facile one-step solution-based method to prepare anisotropic DNA-functionalized gold nanoparticles (a-DNA-AuNP) will be reported. The particles are formed via ligand competition between thiolated hydrophilic DNA and thiolated hydrophobic phospholipid. Subsequent exchange of DNA strands on the anisotropic particle allows regioselective hetero- and homo-nuclear assembly with high monodispersity, as well as regioselective functionalization of two different DNA strands for diverse applications.

 

Forming of Janus Particle by Adsorption and Phase Separation
Donghai Gai, Mechanical Science and Engineering

Tuesday, September 24, 2013
1000 MNTL, 12:30 - 1:00 PM

Abstract: Janus particles possess two or more distinct properties on their surfaces. This asymmetric surface structure leads to interesting properties and enables potential applications in biomedical and biological fields. In this presentation, we focused on the competitive adsorption process of Au/PS Janus particles. Based on experimental observations, we used a coarse-grain molecular dynamics (CGMD) model to seek mechanistic explanation of forming of Janus-type surface structures. Our simulations suggest that the two regions with different properties would not form two hemispheres. The interface between regions of different properties is more likely to be curve similar to that on a tennis ball or baseball.