Shouheng Sun - US grants

Technical Abstract

This project aims to develop novel composite nanomaterials with a structure similar to the dumbbell that has two different functional nanoparticle units with one being magnetic ferrite (MFe2O4), iron, cobalt, nickel, iron-nickel, or cobalt-iron, and the other metallic gold, silver, platinum, or palladium. These two functional units are physically linked by epitaxial growth of one crystal on another. The epitaxial linkage between two particles can be considered as a nanoscale junction, and electrons in one nanoparticle are capable of transferring across the interface to another nanoparticle. This junction effect can modify the electronic structure of both particles in the dumbbell structure, leading to novel physical and chemical properties that do not exist in the single component nanoparticles. The synthetic control in size, shape and interconnection of the composite nanostructures, achieved in this proposal, will allow the fine tuning of the junction effect in the dumbbell structures, facilitating the rational design and synthesis of advanced composite nanomaterials with optimum properties for catalytic applications.

Non-technical Abstract

The proposed research represents a new direction in the study of solid-state composite nanostructures. It will provide new contents for both Solid State Chemistry
and Nanoscale Materials: Synthesis and Applications, two courses the PI has been teaching in Browns undergraduate and graduate classes. The composite nanostructure and the rational approach to it will further enrich the Nanoscience and Nanotechnology
education programs in Browns Chemistry, Physics, Engineering and Life Science
Departments. The proposed research will contribute an essential part to the education of
Science and Engineering students to meet tomorrows challenge in Nanoscience and
Nanotechnology. Timely dissemination of the research results will be to the
Science/Engineering students at Brown during the class hours, and to the scientific community and general public through conference/seminar presentations and
journal/patent publications.

[unreadable] DESCRIPTION (provided by applicant): This application aims to develop composite magnetic nanoparticles with controlled surface functionalization and stability in physiological conditions for applications in targeted delivery of platin-like anticancer molecules to tumor cells, and, specifically to study the effectiveness of the platin nanoparticles in elimination of the glioma cells. The work is based on our preliminary research on the synthesis and surface functionalization of monodisperse magnetic iron-based nanoparticles, including Fe3O4, core/shell Fe/Fe3O4, and dumbbell-like Au-Fe3O4 nanoparticles, and may lead to a solution for highly efficient platin-based cancer therapy in the near future. The multifunctional nanostructures proposed here are illustrative of the exciting possibilities that can emerge from the union of nanoscience and medicine. The selective delivery of therapeutic drugs to malignant tissues constitutes one of the greatest challenges in cancer research. We propose that carefully designed bifunctional nanoparticles may provide an exciting practical vehicle to achieve selective and efficacious platin drug delivery. The composite nanoparticles, as shown in Figure 1, have both magnetic iron oxide and optically active noble metal of Au (or Ag) nanoparticle units. The different surface chemistry offered by this composite structure will facilitate the simultaneous attachment of special peptides and cisplatin-like anticancer drugs for the target specific cell recognition and cell entry. The detailed surface functionalization of the composite nanoparticles is also shown in Figure 1, in which the Fe3O4 particles are coated with a monoclonal antibody (Ab) or peptides via polyethylene glycol (PEG) and dopamine and the Au nanoparticles are linked to a TAT-like peptide (Nuclear Localization signal, NLS) through a platin complex and PEG unit. The monoclonal antibody will be used to target an antigen on the surface of tumor cells, while the NLS is to induce nanoparticle penetration through nuclear membrane. When the functionalized nanoparticles are within the tumor cell nucleus, an alternating magnetic field will be applied to remotely heat the magnetic nanoparticles, and the resultant heat will break the Pt-O bond in the structure and induce the formation of an active Pt coordination site that can readily attach to DNA strands, leading to the interruption of the DNA excision repair system and consequent cell death. The composite nanoparticles can also serve as highly sensitive multifunctional labels for the detection of trajectories of the particles within the cells by either magnetic resonance image (MRI) on iron oxide nanoparticles or electron/optical microscopic image on Au (or Ag), facilitating quantification of transporter-conjugate uptake in tumor cells. The ultimate goal of this application is to provide nanoparticle based therapeutics for successful cancer therapy. [unreadable] [unreadable] [unreadable]

Technical Abstract

This MRI proposal by Brown University requests support for the acquisition of an FEI NOVA 600i Nanolab DualBeam SEM/FIB for nanoscale prototyping, machining, characterization and analysis of structures in the sub-100-nm regime. Research at Brown spanning engineering, physics, chemistry, geology, and medicine is focused on research that has, at its core, the manipulation and characterization of materials on the nanoscale. Some ongoing research that will make use of the new Dual Beam instrument includes: studies of high strain rate deformation of steel where nanoscale features of highly localized adiabatic shear bands (ASB) will be extracted for TEM analysis; creation of nanopore-based prototype device structures for biomolecule analysis that require the selective metallization of e-beam created pores; generation of initiation cracks in multiphase structural materials, in situ monitoring of crack propagation, and the reconstruction of the crack path by serial-sectioning and electron backscatter diffraction (EBSD); manipulation of nanoparticle arrays for patterned magnetic media applications; and minimally invasive, selective removal of inclusions for the identification of the origins of priceless archeological glass samples. More broadly, the selected instrument will provide Brown researchers with the ability to create, modify, and characterize complex structures on the nanoscale, e.g. to extract TEM samples from specific morphological features, to produce three-dimensional serial sections for EBSD analysis of microstructure, and to fabricate unique test structures for examining physical properties of nanomaterials. The growth in nano-materials research at Brown has strained the existing capacity of our Electron Microscope Central Facility (EMCF) and has exposed an urgent need for the capabilities that can only be provided by a Dual Beam FIB/SEM instrument. When added to the Brown EMCF user facility, this tool, the only one in Rhode Island, will be available to all researchers in the state and southeast New England.

Non-Technical Abstract

With the acquisition of a new dual beam SEM/FIB, Brown University researchers will now be able to both see and manipulate nanomaterials in a way that will allow the creation of prototype nanomachines and structures on the nanoscale. In the last century, the electron microscope allowed actual photographic images to be formed of features in materials that are just a few atoms or molecules in size, and impossible to see by other means. Now, a new type of tool (the dual beam SEM/FIB) uses electron beams and focused ion beams to simultaneously see and touch on the nanoscale, allowing scientists to assemble new materials and devices with tailored mechanical, chemical, and/or optical properties. Researchers at Brown in Engineering, Physics, Chemistry, Geology, Biology, and Archeology will use the capabilities of the new dual beam SEM/FIB (the only one in Rhode Island) to create, modify, and characterize nanomaterials in a wide array of applications, including devices for the detection of DNA and other biomolecules, new magnetic storage devices, and design of stronger and lighter materials.

ABSTRACT

Integration of Dynamic Sensing and Actuating of Neural Microcircuits
PI: Arto V. Nurmikko

The proposed EFRI program aims to develop transformative paradigms in our understanding of the complex nonlinear dynamics of brain microcircuits and their function, by developing and fusing a new generation biosensing (recording) and actuation (neurostimulation) techniques to a potent toolbox. The proposed research engages brain circuits with external photonic and microelectronic interfaces in animal models, in particular for the study of the so-called "working memory" - the brain's "random access memory". At the neuroengineering level, the proposed research integrates new set of neural sensing and actuation tools on the microscale that are applied to engage with specific sensing and planning action by the brain - in particular the dynamics of information processing in the prefrontal cortex. A key experimental driver is the development of a new micro-optical/photonic device technology that will enable precise spatio-temporal targeting through sensory pathways of cortical microcircuitry and the imaging of this circuitry in real time in specific animal models. The unique device technology elements in the sensor/actuator engineering integrate ultracompact multi-element arrays of light emitters and microelectronic chip-scale sensors for excitation and mapping of the brain microcircuitry in real-time, which has been rendered both stimulus responsive and recordable by cellular-level genetic and nanomaterial sensitizing. The goal of the development of sensing/actuation microtools with associated brain science paradigms is to pave way for microdevice interfaces for bidirectional access across a population of neurons in the brain. Bidirectionality requires that both neural recording and neural stimulation can be achieved simultaneously at cellular level for multiple neurons, and ultimately multiple brain sites, spatially and temporally. Development of a class of specific brain-interfaces probes which synergize approaches from contemporary photonics/optoelectronics for "reading" and "writing" neural information from/to brain's microcircuits is the contributing aim of this planned EFRI proposal.

In a broader context, the research aims to facilitate the implementation of a closed-loop feedback compact device technology that offers the promise of entirely new classes of neural interfaces for (i) advancing the understanding of the brain from sensing to actuation- with cellular level resolution of microcircuit dynamics, (ii) aim the application of the technology to potentially therapeutic and prosthetic applications. For example, the study of the working memory function in the brain is closely associated with neurological diseases such as schizophrenia, attention deficit disorder and has been linked to epilepsy. The team aims to leverage the research outcomes from this program in mammalian animal models (in vitro and in vivo) so that key brain science paradigms such as the fundamentally important "working memory" will find translation to human neuroscience and rehabilitative goals. By including within the team a clinical neurology interface, our proposed research is envisioned to contribute to our unraveling of neurological disease, pave way for elucidating and exploring the applicability the nature of the brain-like systems to other technologies, as well as improve U.S. competitiveness in the global economy through advanced technology development in a frontier area at the intersection of physical and life sciences. The research on these topics is also expected to create a generation of "neuroengineering" graduate students with true interdisciplinary education, as well as innovative businesses and entrepreneurs.

0922667
Paine
Brown U.

"This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5)."

Technical Abstract

This MRI proposal by Brown University requests support for the acquisition of an FEI Tecnai S20 transmission electron microscope (TEM) to serve the nanoscale imaging and micro/nano-characterization needs of the local research community. The proposed instrument addresses the need at Brown for a modern TEM imaging tool that will allow both conventional materials science studies for the understanding of the microstructure of materials used in electronic, structural, and biological applications and, at the higher resolutions at lower energies available with a field emitter (FE) source, new applications in biomedical and soft-matter physics. This tool will provide both the versatility and flexibility to satisfy the needs of our diverse research community by combining high performance in all imaging and diffraction modes with the ease of operation needed in a multi-user materials research environment. It will enable new material sciences research pursued by the faculty and students in departments across the physical sciences and beyond at Brown, including Engineering, Physics, Chemistry, Geology, Biology, Archaeology and Biomedicine. Some ongoing research that will make use of the new FE TEM includes: studies of the nanoscale features of highly localized adiabatic shear bands formed in high strain rate deformation of steel; creation of nanopore-based prototype device structures for biomolecule analysis; analysis of interfaces and microstructure in the materials used in oxide electronics; understanding growth-related crystallographic defects in nanowire structures fabricated via novel chemical pathways; and evaluation of inclusions for the identification of the origins of archeological glass samples. More broadly, the selected instrument will provide the local research community with a capability that is not currently available anywhere in the state of Rhode Island.

Non-Technical Abstract

The Brown University materials research community encompasses a diversity of disciplines that share a common interest in understanding materials at the atomic level. The acquisition of a modern transmission electron microscope (TEM) will enable researchers in Engineering, Physics, Chemistry, Geology, Biology, and Archaeology to probe, image, and chemically characterize the structure of materials synthesized through a wide range of chemical, metallurgical, physical and biological processes. In the last century, it was discovered that a beam of electrons passing through a thin sample will interact with the sample?s atoms in ways that provide a wealth of chemical and structural insights while simultaneously providing images of features that are just a few atoms or molecules in size and impossible to see by other means. Researchers at Brown and the neighboring research community will use the capabilities of the new field emitter TEM (the only one in Rhode Island) to understand and ultimately control the nano- and micro- structure of materials used in a wide array of applications, Current research at Brown that will utilize this new capability includes: development of devices for the detection of DNA and other biomolecules, new oxide-based electronic devices, battery and fuel cell materials, and it will play a key role in the development of materials that are both strong and lightweight for improved energy efficiency in automotive and aerospace applications.

This award supports the acquisition of a High Magnetic Field and Cryogen-Free Physical Property Measurement System (PPMS) at Brown University. It will enable experimental studies of the physical properties of materials including magnetism, electron transport, and thermodynamic properties. The instrument will provide fundamental information about new materials actively being studied by scientists from the disciplines of Physics, Chemistry, and Engineering. Proposed research using the PPMS includes: (1) spintronics based on half-metallic magnetic nanostructures, (2) magnetic nanoparticles for data storage, energy storage and biomedical applications, (3) low dimensional superconducting nanostructures, (4) type-II superconductors, (5) novel superconducting and spin liquid states, and (6) semiconductor hetero-nanowires. By studying physical properties over a wide range of temperatures and fields, scientists at Brown will uncover the quantum mechanical behavior and physical mechanisms underlying many novel and revolutionary materials. With this new instrument, they will have the ability to investigate the ground state properties of their materials directly, rather than rely on mere extrapolations of measurements conducted at room temperature or low magnetic fields. Since the PPMS provides a myriad of physical characterizations, they will be able to develop theoretical models that can then be almost immediately tested by multiple types of measurements and their correlations. The PPMS will open up new research opportunities for the materials research programs, and will help to reveal as yet unexplored physical phenomena while simultaneously producing devices of great practical significance. The proposed research not only will advance the development of material science, but also will lead to prototyping the next generations of spin-based electronics and semiconductor devices, thereby directly influencing the future development of the semiconductor industry.

This instrument will be used as an educational tool for graduate and undergraduate training. With this instrument, they will be able to teach students the fundamental properties of modern materials, develop a deeper understanding of physical mechanisms, and also provide invaluable practical experience in advanced characterization techniques. In particular, undergraduate students will use this sophisticated instrument for their research projects, thereby offering a unique opportunity for high-level investigations. These students will form the next generation of materials scientists in the United States, ensuring the development of the field and helping the US assume and maintain a preeminent role. The proposed research will also generate new basic knowledge and data on novel spintronic, superconducting, and semiconductor materials that can be leveraged to develop potentially revolutionary devices for widespread implementation in multiple arenas including information technology, medicine, and education.

With the support of the Chemical Catalysis program in the Division of Chemistry, Professors He and Ung at the University of Connecticut and Professor Sun at Brown University are designing new hybrid materials for selective electrochemical activation of carbon dioxide (CO2). The team will utilize synthetic polymers to coat and protect copper-based catalysts, allowing the resulting hybrid materials to be more robust and efficient for CO2 electroreduction to yield value-added hydrocarbon products. The use of renewable electricity to convert CO2 to useful chemical products is likely to be an important component of sustainability. This collaborative project will involve undergraduate, graduate, and postgraduate researchers from two universities, and will utilize each groups’ expertise in polymer, nanomaterial, organometallic, surface science, and electrochemistry. The results obtained from this project will be disseminated to science and engineering students through joint meetings, courses, undergraduate research activities, and outreach activities. The PIs are collaborating with local high schools and outreach programs in the southern New England region to attract students into studies and potential career paths in STEM (science, technology, engineering and mathematics) fields.

With the support of the Chemical Catalysis program in the Division of Chemistry, Professors He and Ung at the University of Connecticut and Professor Sun at Brown University are studying new Cu-based nanocubes functionalized with synthetic polymer ligands toward stable and selective electroreduction of CO2. The central hypothesis of this proposal is twofold: i) the incorporation of Cu-based nanocubes with rationally designed synthetic polymers to prevent interparticle coalescence and surface corrosion during electroreduction, and ii) hydrophobic polymer ligands to control the microenvironment of nanocubes and improve the selectivity of nanocubes. Polymer ligands terminated with N-heterocyclic carbenes (NHCs) will be anchored on Cu, copper nitride (Cu3N) and core-shell Cu/Cu3N nanocubes through stable NHC-Cu bonds. Those nanocubes have maximum (100) surface exposure to efficiently promote C-C coupling and form C2+ hydrocarbon products. Polymer NHC ligands will balance the localized proton concentration nearby the surface of nanocubes through control over polymer chain lengths and hydrophobicity to achieve maximum catalytic proton-assisted CO2 reduction to C-C coupling products and minimize proton reduction reaction. The Cu-NHC bond stability and the structural integrity of polymer-grafted Cu and Cu3N nanocubes will be probed using in situ spectroscopies and microscopies. The polymer chain length dependent diffusion properties will be quantitatively measured and correlated to the catalytic performance of Cu and Cu3N nanocubes. The successful demonstration of the active and efficient polymer NHC-Cu nanocubes for CO2 electroreduction also allows tackling more broadly the long-term stability issues of all other cathodic nanocatalysts to improve the sustainability of electroreduction.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.