California NanoSystems Institute
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June 08, 2010

Ramamoorthy Ramesh
Physics and Materials Science and Engineering
University of California, Berkeley
Lawrence Berkeley National Laboratory

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Controlling and manipulating ferromagnetism with an electric field using multiferroic oxide heterostructures
Complex perovskite oxides exhibit a rich spectrum of functional responses, including magnetism, ferroelectricity, highly correlated electron behavior, superconductivity, etc. The basic materials physics of such materials provide the ideal playground for interdisciplinary scientific exploration. Over the past decade we have been exploring the science of such materials (for example, colossal magnetoresistance, ferroelectricity, etc) in thin film form by creating epitaxial heterostructures and nanostructures. Among the large number of materials systems, there exists a small set of materials which exhibit multiple order parameters; these are known as multiferroics. Using our work in the field of ferroelectric and ferromagnetic oxides as the background, we are now exploring such materials, as epitaxial thin films as well as nanostructures. A particularly interesting problem is that related to electric field control and manipulation of ferromagnetism. In this talk I will describe to you some aspects of such materials as well as the scientific and technological excitement in this field. Finally I will share my ideas on the most exciting open problems and emerging directions in multiferroics and beyond into the realm of Energy.

May 25, 2010

Scott Manalis
Biological and Mechanical Engineering

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Microfluidics for measuring mass: from a single virus to a growing cell
My laboratory is developing microfluidic approaches based on fluid-filled mechanical resonators that enable precise measurements of mass, volume and density to be correlated to molecular measurements during the cell cycle. In this talk, I will describe how such approaches are being used to investigate the coordination of cell growth and division in normal and cancer cells. I will also present recent progress towards developing nanofluidic resonators for weighing individual viruses in solution.

May 19, 2010

P. M. Chaikin
Center for Soft Condensed Matter Research
New York University

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Self-Replication Of Micro and NanoStuff
We want to make a "non-biological" system which can self-replicate. The idea is to design particles with specific and reversible and irreversible interactions, introduce seed motifs, and cycle the system in such a way that a copy is made. Repeating the cycle would double the number of offspring in each generation leading to exponential growth. Using the chemistry of DNA either on colloids or on DNA tiles makes the specific recognition part easy. In the case of DNA tiles we have in fact replicated the seed at least to the third generation. The DNA linkers can also be self-protected so that particles don't interact unless they are held together for sufficient time - a nano-contact glue. We have also designed and produced colloidal particles that use novel "lock and key" geometries to get specific and reversible physical interactions.

May 11, 2010

Andrew Maynard
Director of the Risk Science Center
University of Michigan

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Sharon Dunwoody
School of Journalism and Mass Communication
University of Wisconsin-Madison

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Two seminars for ICEIN on Safe Nanotechnologies and Public Perceptions of Nanotechnology
CNSI and CEIN are co-hosting two seminars in conjunction with the 2010 International Conference on Environmental Implications of Nanotechnology (ICEIN 2010). Dr. Maynard's talk at 4:30pm will be preceded at 4:00pm by a short talk from Sharon Dunwoody from the School of Journalism and Mass Communication at the University of Wisconsin-Madison. All are invited to both talks.

Maynard Talk Title: Developing Safe Nanotechnologies - Are We Getting What We Ask For?
(4:30pm-5:30pm, CNSI Auditorium)

Maynard Abstract: Few people would disagree that emerging technologies have the potential to lead to new environmental risks. Risks that are not readily apparent, assessable or manageable seem to be intricately linked to advances in science and technology resulting in innovative new products and processes. However, strategically dealing with new risks as they emerge is proving to be far from straight forward. Over the past ten years, the push towards developing technologies based on nanoscale engineering has led to a rapidly increasing body of risk-related research. Yet researchers, decision-makers and others continue to struggle to articulate the problems they are trying to solve. Nevertheless, if nanoscale science and innovation are to translate to sustainable, safe and socially valuable technologies, it is essential that we get this first step in the risk assessment process right - asking the science-based questions that will ultimately lead to science-informed decision-making. In recent years, widely used definitions of nanotechnology and engineered nanomaterials have confounded the process of asking well-formed risk-relevant questions. Looking to the future, research leading to safe nanotechnologies will likely depend on rethinking our dependence on definitions. Rather, principles should be considered which enable well-formed risk-relevant questions to be constructed, and significant emerging challenges to be identified. In rethinking how we formulate questions on nanotechnologies-related risks, we are more likely to get the answers we need, rather than simply those that we look for.

Biography: On April 1, 2010 Dr. Maynard began a new position as Director of the Risk Science Center at the University of Michigan. He is internationally recognized as a research leader and lecturer in the fields of aerosol characterization and the implications of nanotechnology to occupational health. He trained as a physicist at Birmingham University in the UK, and after completing a Ph.D. in ultrafine aerosol analysis at the Cavendish Laboratory, Cambridge University (UK), joined the Aerosols research group of the UK Health and Safety Executive. In 2000 he moved to the National Institute for Occupational Safety and Health (NIOSH) in the USA, where he focused on addressing nanoparticle exposure in the workplace.
Sharon Dunwoody

Talk Title: Nanotechnology in the Public Eye
(4:00pm-4:30pm, CNSI Auditorium)

Abstract: Frequent public opinion surveys underscore two patterns in American perceptions of nanotechnology: Despite the sense that an individual knows little about nano (pattern #1), he/she still regards nanotechnology and its commercial uses with something bordering on benign indifference (pattern #2). In this brief talk, I will provide an update on public perceptions but will then concentrate on characteristics of the information landscape that may contribute to these patterns.

Biography: Sharon Dunwoody is Evjue-Bascom Professor in the School of Journalism and Mass Communication at the University of Wisconsin-Madison, as well as Associate Dean for Social Studies in the Graduate School. As a scholar, she focuses on the construction of media science messages and on how those messages are employed by individuals for various cognitive and behavioral purposes. Illustrative of this large domain are her three current research streams: How do media messages influence public perceptions of nanotechnology? How do individuals use information to inform their judgments about environmental risks? What role do perceptions of both journalists and scientists play in the construction of news about science? In addition to numerous articles and book chapters, she has co-edited two volumes, Communicating Uncertainty (Erlbaum, 1999) and Scientists and Journalists (Free Press, 1986), and authored a third book, Reconstructing Science for Public Consumption (Deakin University Press, 1993). A former science writer, she earned the BA in journalism at Indiana University in 1969, the MA in mass communication from Temple University in 1975, and the Ph.D. in mass communication from Indiana University in 1978. Before joining the UW-Madison faculty in 1981, she was on the faculty of the Ohio State University School of Journalism.

May 04, 2010

Donald Tomalia
Director, The National Dendrimer & Nanotechnology Center
Central Michigan University

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In Quest of a Systematic Framework for Unifying and Defining Nanoscience
A "central paradigm and Mendeleev-like periodic system" based on first principles of traditional chemistry/physics has been a missing link in the transformation of nanotechnology from an empirical activity to a predictive science. Such a systematic framework would assist in the a priori design, as well as the quantitation of critical risk/benefit boundaries related to the use and development of nanomaterials. This lecture proposes a systematic framework for unifying and defining nanoscience based on historical first principles that produced the "central paradigm" (i.e., unifying framework) now accepted for traditional small-molecule chemistry[1-2]. As such, a Nanomaterials Classification Roadmap is proposed which divides all nano-matter into Category I: discrete, well defined and Category II: statistical, undefined nanoparticles. We consider only Category I, well-defined nanoparticles (i.e., >90% monodisperse), which are quantized as a function of Critical Nanoscale Design Parameters (CNDPs) such as: (a) size, (b) shape, (c) surface chemistry, (d) flexibility, (e) architecture and (f) elemental composition. Classified as either Hard (H) (i.e., inorganic-based) or Soft (S) (i.e., organic-based) categories, these nanoparticles were found to manifest pervasive atom mimicry features that include: 1) a dominance of zero-dimensional (0-D) core-shell nano-architectures, 2) the ability to self-assemble or chemically bond as discrete, quantized nano-units, and 3) exhibit well-defined nanoscale valencies and stoichiometries reminiscent of atom-based elements. These discrete nanoparticles are referred to as Hard or Soft Particle Nano-Element Categories. Many examples describing chemical bonding or self assembly of these nano-elements have been reported in the literature[1-2]. We refer to these Hard-Hard (Hn-Hn), Soft-Soft (Sn-Sn), or Hard-Soft (Hn-Sn) nano-element combinations as Nano-Compounds/Assemblies. Due to their quantized features, many nano-element, nano-compound/assembly categories are reported to exhibit well-defined nano-periodic property patterns. These periodic property patterns are dependent on their quantized nano-features (CNDPs) which dramatically influence intrinsic physico-chemical properties (i.e., melting points, reactivity/self-assembly, sterics, nano-encapsulation), as well as important functional/performance properties (i.e., magnetic, photonic, electronic and toxicological properties). The importance of these CNDP's has been recently demonstrated by the publication of the first Mendeleev-like nano-periodic tables by Percec, et al. [3]. These nano-periodic tables predict (i.e., with 85-90% accuracy) the a priori self assembly mode of [S-1] type dendrons/dendrimers as a function of: (a) size, (b) shape and (c) surface chemistry. This fulfills our predictive "nano-periodic system" hypothesis and is expected to be extended and applicable to all facets of nanomaterials design. We propose this perspective as a first step toward more clearly defining synthetic nano-chemistry, as well as providing a systematic framework for unifying nanoscience.

[1] D.A.Tomalia, J. Nanoparticle Research (2009), 11, 1251-1310.
[2] D.A. Tomalia, Soft Matter (2010), 6, 456-474.
[3] B.M. Rosen, V. Percec, et al., J. Am. Chem. Soc. (2009), 131, 17500-17521.

April 27, 2010

Stephen Allen Boppart
Electrical and Computer Engineering
University of Illinois

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Magnetomotive Molecular Nanoprobes
The diagnostic, interrogational, and therapeutic potential of molecular nanoprobes is rapidly being investigated and exploited across virtually every biomedical imaging modality. While many types of probes enhance contrast or delivery therapy by static localization to targeted sites, significant potential exists for utilizing dynamic molecular nanoprobes. Recent examples include molecular beacons, photoactivatable probes, or controlled switchable drug-releasing particles, to name a few. We have developed a novel class of dynamic molecular nanoprobes that rely on the application and control of localized external magnetic fields. These magnetomotive molecular nanoprobes can provide optical image contrast through a modulated scattering signal, can interrogate the biomechanical properties of their viscoelastic microenvironment by tracking their underdamped oscillatory step-response to applied fields, and can potentially delivery therapy through nanometer-to-micrometer mechanical displacement or local hyperthermia. This class of magnetomotive agents includes not only magnetic iron-oxide nanoparticles, but also new magnetomotive microspheres or nanostructures with embedded iron-oxide agents. In vitro three-dimensional cell assays and in vivo targeting studies in animal tumor models have demonstrated the potential for multimodal detection and imaging, using magnetic resonance imaging for whole-body localization, and magnetomotive optical coherence tomography for high-resolution localization and imaging.

April 20, 2010

Chris Murray
University of Pennsylvania

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Programming multi-component nanocrystal assembly: Nanocrystals built to order
The synthesis of colloidal nanocrystals with controlled crystal shape, structure and surface passivation provides a rich family of nanoscale building blocks for the assembly of new solid thin films and novel devices. The tunability of the electronic, magnetic, and optical properties of the nanocrystals has lead to them being compared to a set of "artificial atoms". This talk will provide key insights into the development of "best practices" in preparation, isolation and characterization of semiconducting quantum dots, nanocrystal phospors and magnetic nanoparticles. A very brief discussion of the organization of monodisperse nanocrystals in to single component superlattices that retain and enhance many of the desirable mesoscopic properties of individual nanocrystals will transition into a discussion of multicomponent assembly. The potential to design new materials expands dramatically with the creation binary nanocrystal superlattices BNSLs. I will show how we synthesized differently sized PbS, PbSe, CoPt3, Fe2O3, Au, Ag and Pd nanocrystals and then these nanoscale building blocks into a rich array of multi-functional nanocomposites (metamaterials). Binary superlattices with AB, AB2, AB3, AB4, AB5, AB6 and AB13 stoichiometry and with cubic, hexagonal, tetragonal and orthorhombic packing symmetries have been grown. The opportunity to optimize materials for applications in solution processable photovoltaic systems and phosphor based luminescent concentrators will be highlighted. We have also identified a novel method to direct superlattice formation by control of nanoparticle charging. Although modular nano-assembly approach has already been extended to a wide range of nanoparticle systems, we are confident that we have produced only a tiny fraction of the materials that will soon accessible. Recent progress in the extensions to the formation of quasicrystalline colloidal phases will be shared. Progress toward large area (~1cm2) processing and and integration and device fabrication.

April 13, 2010

Robert Tanguay
Environmental and Molecular Toxicology
Environmental Health Center
Oregon State University

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Fishing to define the nanoparticle properties that dictate biological responses
The rapid rate of discovery and development in the nanotechnology field will undoubtedly increase both human and environmental exposures to engineered nanoparticles. Whether these exposures pose a significant risk remains uncertain. Despite recent collective progress there remains a gap in our understanding of the nanomaterials physiochemical properties that drive or dictate biological responses. The development and implementation of rapid relevant and efficient testing strategies to assess these emerging materials prior to large-scale exposures could help advance this exciting field. I will present a powerful approach that utilizes a dynamic in vivo zebrafish embryonic assay to rapidly define the biological responses to nanoparticle exposures. Early developmental life stages are often uniquely sensitive to environmental insults, due in part to the enormous changes in cellular differentiation, proliferation and migration required to form the required cell types, tissues and organs. Molecular signaling underlies all of these processes. Most toxic responses result from disruption of proper molecular signaling, thus, early developmental life stages are perhaps the ideal life stage to determine if nanomaterials perturb normal biological pathways. Through automation and rapid throughput approaches a systematic and iterative strategy has been deployed to help elucidate the nanomaterials properties that drive biological responses.

Robert Tanguay is an Associate Professor in the Department of Environmental and Molecular Toxicology, Director of the Sinnhuber Aquatic Research Laboratory, Director of the NIEHS Toxicology Training Grant, and the Director of a NCRR Veterinary Training Grant in Aquatic Models for Biomedical Research. He received his PhD in Biochemistry from the University of California-Riverside and postdoctoral training in developmental toxicology from the University of Wisconsin-Madison. His group has demonstrated that zebrafish provide an ideal discovery platform for rapid throughput in vivo assessments and for identifying the gene products that underlie the phenotypic responses to environmental insults.

April 06, 2010

Kam Moler
Stanford University

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Tireless electrons in tiny metal rings
The magnetic flux quantum, hc/e, plays a special role in the quantum states of charged particles. In this talk, I will describe how advances in nanomagnetic measurements enable us to probe quantum-mechanical phase-coherent states through their mesoscopic magnetic phenomena. Enabling technological advances include nano-SQUIDs that can measure magnetic signals smaller than the dipole moment of a hundred electrons, with nine orders of magnitude background cancellation.

Normal metal rings have a finite resistance, even if they are small and cold. Nevertheless, quantum mechanics says that in a magnetic field, a mesoscopic normal metal ring should have a persistent current flowing forever around it. This fundamental feature of metallic states has generated much work, with major controversies, but a limited number of experiments. Previous experiments on individual gold rings disagreed strongly with theory. With our scanning SQUID microscope, we found good agreement between theory and experiment for persistent currents in many individual mesoscopic gold metal rings, measured one ring at a time [1]. Similarly, the ring geometry provides a good test of the theory of fluctuations in one-dimensional superconductors [2].

We also use nanomagnetic measurement technologies to study vortices in unconventional superconductors such as pnictides [3], where the superfluid density provides clues to the superconducting state, and cuprates [4], where our measurements of mechanics of single-vortices confirm the picture of vortices as one-dimensional elastic objects moving through materials-determined pinning landscapes.

Scanning SQUID microscopy also provides useful metrology for devices, for example by revealing the presence of a surprising spin-glass-like interface state associated with several metals [5]. These surprising spins are likely related to decoherence in superconducting qubits.

[1] H. Bluhm et al., Physical Review Letters 102, 136802 (2009)
[2] N.C. Koshnick et al., Science 318, 1440 (2007)
[3] C. W. Hicks et al., Physical Review Letters 103, 127003 (2009)
[4] O. M. Auslaender et al., Nature Physics 5, 35 (2009)
[5] H. Bluhm et al., Physical Review Letters 103, 026805 (2009)
March 30, 2010

Selim Unlu
Electrical and Computer Engineering
Boston University

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Optical Interference for Nanoscale Biological Imaging and Detection
We have utilized basic principles of optical interference and resonance in biological applications demonstrating nanometer scale measurement capability in fluorescence microscopy and label-free sensing of protein binding and viruses in a high-throughput micro-array format. We have developed a technique ? spectral self-interference fluorescent microscopy (SSFM) ? that transforms the variation in emission intensity for different path lengths used in fluorescence interferometry to a variation in the intensity for different wavelengths in emission, encoding the high-resolution information in the emission spectrum. Using SSFM, we have estimated the shape of coiled single-stranded DNA, the average tilt of double-stranded DNA of different lengths, and the amount of hybridization. The determination of DNA conformations on surfaces and hybridization behavior provide information required to move DNA interfacial applications forward and thus impact emerging clinical and biotechnological fields. Recently, we have also applied SSFM to study the conformational changes of polymers and DNA-protein complexes. Direct monitoring of primary molecular binding interactions without the need for secondary reactants would markedly simplify and expand applications of high-throughput label-free detection methods. We developed a simple interferometric technique ? Spectral Reflectance Imaging Biosensor (SRIB) ? that monitors the optical phase difference resulting from accumulated biomolecular mass. Dynamic measurements were made at ~10 pg/mm2 sensitivity. We have also demonstrated simultaneous detection of antigens and antibodies in solution using corresponding probes on the SRIB surface as well as label-free measurements of DNA hybridization kinetics.