Bulletin of the American Physical Society
2005 APS March Meeting
Monday–Friday, March 21–25, 2005; Los Angeles, CA
Session Y15: Biosensors and Hybrid Biodevices |
Hide Abstracts |
Sponsoring Units: FIAP Chair: Pritraj Mohanty, Boston University Room: LACC 405 |
Friday, March 25, 2005 11:15AM - 11:27AM |
Y15.00001: Direct microscopic observation of localized protein bindings in topographically patterned lipid rafts Tae-Young Yoon, Cherlhyung Jeong, Sin-Doo Lee, Joon Heon Kim, Myung Chul Choi, Mahn Won Kim Signal transductions through binding of ligands to cell membrane receptors are the most fundamental way of cell-to-cell communications in multicellular organisms. Important classes of the cell membrane receptors are predominantly concentrated at the phase-separated domains of membranes, the lipid rafts. By localizing lipid rafts at predetermined sites on membranes, cells control the distribution of the ligand bindings to membrane receptors, thereby manipulating the position and intensity of the signal transductions. Thus, prescribed localization of lipid rafts in model membranes could become an important biomimetic methodology of studying cell-to-cell signaling and its engineering in laboratory environments. Here, we demonstrate that topographical nano structures incorporated in supported membranes control the organization processes of lipid rafts; formation, growth, and clustering, by generating elastic energy barriers. We made direct microscopic observations of localized protein bindings in topographically patterned lipid rafts that were prepared by micro-fabrication and nano-corrugation technologies. This topographical concept of controlling the distribution of ligand-membrane receptor binding processes, not disrupting the integral structure of lipid membranes, should provide a viable platform to study human diseases and drug delivery systems. [Preview Abstract] |
Friday, March 25, 2005 11:27AM - 11:39AM |
Y15.00002: Physical evidence for a glue holding mineralized collagen fibrils together in bone* P. Hansma, G.E. Fantner, J.K. Kindt, P. Thurner, M.M. Finch, P. Turner, G. Schitter, B. Erickson, Z. Schriock, L.S. Golde, E. Strong, S.F. Udwin Evidence from Atomic Force Microscope indentation, pulling and imaging, and macroscopic testing and enzymatic digestion, suggests that collagen fibrils and mineral plates are not the only components of bone with mechanical roles. A ``glue'' appears to bind mineralized collagen fibrils together. Order of magnitude calculations show that less than 1{\%} by weight of this ``glue'' profoundly affects bone fracture resistance, as it involves a remarkable natural toughening and strengthening system: sacrificial bonds and hidden length. This system dissipates large amounts of work against entropic forces while stretching out the hidden length that is exposed when sacrificial bonds break. This appears to occur when mineralized collagen fibrils are torn apart or slid against each other during bone fracture. In bone, this system depends on multivalent positive ions such as calcium ions, which allows us to follow its influence up to macroscopic fracture testing levels. Many bone matrix proteoglycans and glycoproteins have negatively charged groups at physiological pHs that could be bound together into sacrificial bonds by multivalent positive ions, and are thus natural candidates for this ``glue.'' We cannot rule out a possible involvement of nonfibrillar collagen. Precisely which candidates are involved is yet to be determined. *NSF MRL DMR00-80034, NIH GM65354, NASA BiMAT URETI NCC-1-02037 (00000532), Veeco, USARL ARO DAAD19-03-D-0004 [Preview Abstract] |
Friday, March 25, 2005 11:39AM - 11:51AM |
Y15.00003: Induced electrostatic interactions between atomic force microscope tip and iridovirus Sergei Lyuksyutov, Olga Mayevska, Pavel Paramonov, Shane Juhl, Richard A. Vaia Electrostatic nanolithography based on atomic force microscopy (AFMEN) is implemented to study interactions between an AFM tip and iridovirus assembly on a conductive substrate. Iridovirus is composed of proteins. Certain sequences of natural amino-acids arranged into a helix and folded in ternary structural pattern to form capsomers. Those are the building blocks of the virion capsid. AFMEN implemented on the iridovirus culture deposited on the surface of Au (111). In this proof-in-principle experiment the culture was deluted in water, poured on the gold surface and dried for 24 hours. An AFM tip was manipulated above the iridovirus surface drawing a square of 2$\times $2 $\mu $m$^{2}$ so the virus attracted toward the tip forming piles on the otherwise uniform surface. The robust implementation of AM-AFMEN$^{ }$permits marking an individual virus in air under ambient humidity. Insight of structural protein changes with field magnitude, the threshold character of activation energy of protein re- arrangement, electrostriction, and the influence of filed-induced water condensation are discussed. [Preview Abstract] |
Friday, March 25, 2005 11:51AM - 12:03PM |
Y15.00004: The Micro-patterned Device for Cell Attachment using New Extracellular Matrix S.K. Chae, C. Kim, D.S. Na, J.W. Lee, B.K. Ju, C.H. Lee, H. Lee, S.U. Kim, C.N. Hwang, Y.S. Jung, S.H. Lee In this study, we tried to culture mouse P19EC (embryonal carcinoma) stem cell on a new ECM substrate, and we found the new source of the bio-compatible ECM material from zebrafish. The new ECM material is composed primarily of polysaccharide and cross-linked by a N-linked saccharide. We integrated the new ECM material into microwalls of a micro-patterned microdevice for cell attachment. The result of cell adhesion and proliferation on the new ECM was compared with those of other ECM substrates. The surface morphology of the new ECM substrate was investigated using atomic force microscope and the surface properties like electrostatic potential and wettability were measured by contact angle, respectively. [Preview Abstract] |
Friday, March 25, 2005 12:03PM - 12:15PM |
Y15.00005: DFT Study of Amino Acids on Si Surface for Hybrid Organic-Semiconductor and Protein-Semiconductor Structures Guilluame Dupont, Charles Musgrave We have used DFT to investigate the formation of hybrid organic- inorganic interfaces between amino acids and silicon surfaces. Not only do amino acids provide a large library of novel organic attachment chemistries to semiconductors, but the reactivity of their side chains also serve as models for the local interactions involved in forming protein- semiconductor interfaces. The amino acid common group is found to react through several low energy pathways, with OH dissociation of the carboxyl group being the most kinetically favorable. Consequently, reaction of amino acids through the amine and carboxyl functionalities is not expected to be selective. The reactivity of many of the amino acids are similar to those of their simpler organic analogues, although we have found several cases which display unique, and possibly useful properties not exhibited by organic functionalities previously considered. Of special interest are attachments of particular amino acid side chains which create quantum mechanical resonances between the amino acid and the semiconductor substrate that may find application in molecular electronics. [Preview Abstract] |
Friday, March 25, 2005 12:15PM - 12:27PM |
Y15.00006: Biotin chemisorption on clean and hydroxylated Si-SiC(001) surfaces Yosuke Kanai, Giancarlo Cicero, Giulia Galli, Annabella Selloni, Roberto Car In recent years, there have been substantial experimental efforts toward achieving nanoscale functionalization of semiconductor surfaces. One of the main motivations of such experiments is biosensing application. Biotin is a leading candidate for such functionalization because of its strong, unmatched affinity to specific proteins such as Streptavidin. On the other hand, silicon carbide (SiC) has emerged as a promising biocompatible material that may be employed in new biomedical devices. Using Density Functional Theory, we have carried out a theoretical investigation of the structural and electronic properties of biotin after chemisorption on both the clean and hydroxylated Si-SiC(001). We find that, upon chemisorption, Biotin retains the electronic properties responsible for its strong affinity to proteins. While the electronic states of the hydroxylated surface undergo negligible changes in the presence of biotin, those of the clean surface are substantially affected by the presence of the molecule. This work was performed under the auspices of the U.S. Department of Energy by University of California Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48. [Preview Abstract] |
Friday, March 25, 2005 12:27PM - 12:39PM |
Y15.00007: Vibrational modes of viruses and virus-based nano-assemblies Alexander A. Balandin, Vladimir A. Fonoberov Viruses have been proposed as biological templates for fabricating identical nanostructures. Various metallic and semiconductor nanowires and nanotubes were fabricated using cylindrical viruses such as tobacco mosaic virus (TMV) and M13 bacteriophage. The knowledge of the phonon (vibrational) modes of the viruses used for nano-templating is important for monitoring the chemical assembly process and understanding carrier transport properties in resulting nanostructures. In this paper we present results of our investigation of the low-frequency phonon spectra of TMV and M13 viruses immersed in air and water [1]. It is demonstrated that the vibrational modes of inorganic nanowires and nanotubes undergo strong modifications when the organic virus is present inside the nanotube. [1] V.A. Fonoberov and A.A. Balandin, Phys. Stat. Solidi B \textbf{241}, R67 (2004); A.A. Balandin and V.A. Fonoberov, J. Biomed. Nanotechnol. \textbf{1}, in press (2005); see also at http://ndl.ee.ucr.edu [Preview Abstract] |
Friday, March 25, 2005 12:39PM - 12:51PM |
Y15.00008: Single-Walled Carbon Nanotube Transporter for Gene Delivery Pu-Chun Ke, Qi Lu, Jessica Moore, Rahul Rao, Katherine Freedman, Apparao Rao Recent studies have shown great promises in integrating nanomaterials in biomedicine. To explore the feasibility of using single-walled carbon nanotubes (SWNTs) as transporters for gene delivery, we have investigated the binding of SWNTs and RNA polymer poly(rU), and the diffusion and the translocation of the SWNT-poly(rU) complexes. Through single-molecule fluorescence imaging, we have found that the pi- stacking dominates the hydrophobic interactions between the carbon rings on tubes and the nitrogenous bases of RNA. Our diffusion study has further demonstrated the feasibility of tracking the motion of water soluble SWNT-poly(rU) complexes. The uptake of SWNT-poly(rU) by breast cancer cells MCF7 was observed using confocal scanning fluorescence microscopy. It was evident that the complexes could penetrate through cell membrane into cytoplasm and cell nucleus. Our cell culture, MTS assay, and radioisotope labeling showed the negligible cytotoxicity of surface modified SWNTs with RNA polymer and amino acids in cell growth medium. These studies have paved the way for gene transfection using SWNTs as transporters. [Preview Abstract] |
Friday, March 25, 2005 12:51PM - 1:03PM |
Y15.00009: Biomolecular Recognition with Functionalized Silicon Nanowires Yu Chen, Agnes Kalinowski, Shyam Erramilli, Pritiraj Mohanty Nanotechnology has the potential to lead to novel techniques for ultra-sensitive biomolecular recognition. We report preliminary results on biomolecular recognition by the measurement of conductance change of bio-functionalized nanowires. The change is primarily due to the contribution of surface states to the conductance, which for larger sensors is dominated by volume effects. The fractional change is greatest for the smallest sensors, due to the increased surface-to-volume ratio. Our silicon nanowires are fabricated from SOI wafer by electron beam lithography, which provides highly controllable nanowire sensors in comparison to other nanoelectronic approaches. We detect ultra-sensitive conductance change at nanoampere-level currents in functionalized nanowires with APTES-modified surface. This work is supported by Department of Defense (CDMRP). [Preview Abstract] |
Friday, March 25, 2005 1:03PM - 1:15PM |
Y15.00010: Optical measurement of DNA torsional modulus under various stretching forces Jaehyuck Choi Optical measurement of DNA torsional modulus under various stretching forces Jaehyuck Choi[1], Kai Zhao[2] Y.-H. Lo[1] [1] Department of Electrical and Computer Engineering, [2] Department of Physics University of California at San Diego, La Jolla, California 92093-0407 We have measured the torsional spring modulus of a double stranded-DNA by applying an external torque around the axis of a vertically stretched DNA molecule. We observed that the torsional modulus of the DNA increases with stretching force. This result supports the hypothesis that an applied stretching force may raise the intrinsic torsional modulus of ds-DNA via elastic coupling between twisting and stretching. This further verifies that the torsional modulus value (C = 46.5 +/- 10 pN nm2) of a ds-DNA investigated under Brownian torque (no external force and torque) could be the pure intrinsic value without contribution from other effects such as stretching, bending, or buckling of DNA chains. [Preview Abstract] |
Friday, March 25, 2005 1:15PM - 1:27PM |
Y15.00011: Nonlinear Analysis of Nanomechanical Biosensors in Viscous Fluids Agnes Kalinowski, Shyam Erramilli, Pritiraj Mohanty Current analytical techniques, such as thin beam approximations, inviscid models and finite element simulations fail to accurately model the behavior of nanomechanical structures such as singly- and doubly-clamped beams, coupled linear structures and beam arrays in viscous fluid. We report the nonlinear analysis of elastic nanomechanical structures in highly viscous, laminar flow fluids. The change in resonant frequency of these nanomechanical structures resulting from surrounding fluid dynamics is compared with fluid-structure analysis using the finite element method. This work is supported by the Department of Defense (CDMRP) and the National Science Foundation. [Preview Abstract] |
Friday, March 25, 2005 1:27PM - 1:39PM |
Y15.00012: Detection of single magnetic bead using InAs micro-Hall sensors for biological applications Goran Mihajlovic, Peng Xiong, Stephan von Molnar, Keita Ohtani, Hideo Ohno, Mark Field, Gerard J. Sullivan We have fabricated and characterized micro-Hall sensors from InAs/AlSb quantum well heterostructures containing a two-dimensional electron gas. The sensors exhibit room temperature field sensitivities as high as 600 $\Omega $/T, mobilities $>$2$\times $10$^{4}$ cm$^{2}$/V$\cdot $s and low 1/f noise which result in an average field resolution down to the sub- gauss range. Measurements were carried out at temperatures below 150 K on a single submicron superparamagnetic bead (d$\sim $0.9 $\mu $m) that are intended to be used as magnetic labels in biological applications [1]. The magnetization showed expected Langevin behavior as a function of applied field with good signal to noise ratio, demonstrating good potential for the sensors to be used as a detection tool in biological applications. We have also measured the magnetic hysteresis for a single ferromagnetic Ni nanowire (d $\sim $ 200nm) using the device. Our ongoing efforts to demonstrate room temperature operation and to develop biocompatible detection schemes utilizing the micro-Hall sensors will be presented. This work was supported by NSF NIRT Grant ECS-0210332 [1] Q. A. Pankhurst et al., J. Phys. D \textbf{36 }R167 (2003) . [Preview Abstract] |
Friday, March 25, 2005 1:39PM - 1:51PM |
Y15.00013: Microring Resonators for Biochemical Sensing Ayca Yalcin, John C. Aldridge, Ketul C. Popat, Tejal A. Desai, Nabil Chbouki, M. Selim Unlu, Bennett B. Goldberg Resonant microcavities have recently become popular for research in optical biosensor applications. Whispering Gallery Mode (WGM) microresonators are preferred as active sensing surfaces due to their high-Q values which provide measurable shifts in mode frequencies as surface characteristics change. In this study, the active sensing surface is a microring resonator vertically coupled to waveguides and mounted to a flow cell. Resonant transmission at a specific wavelength is measured as a function of time as flow solution concentrations are varied, and high sensitivity to surface refractive index changes and repeatability are demonstrated. To investigate Avidin-Biotin binding, surfaces are modified with silane and Avidin, followed by Biotinylated Lectin flow. Surface characterization performed by ellipsometry and XPS shows successful deposition of discrete layers. Preliminary results show detection of binding and near complete regeneration of the sensing surface, indicating a high potential for sensitive and selective biosensor applications of microring resonators. [Preview Abstract] |
Friday, March 25, 2005 1:51PM - 2:03PM |
Y15.00014: A Combinatorial Computational Approach to Optimizing Drug Delivery from Passive Hydrogels S\'ebastien Casault, Gary W. Slater We introduce a new computational approach to design passive drug delivery systems based on porous materials such as hydrogels. The approach uses four tools: a method to establish the exact release pattern from all possible loading sites inside a given hydrogel; a method to generate a large number of hydrogel structures to be tested numerically; a method to compute the loading pattern that would provide the best release curves for a given hydrogel structure; and an optimization method that leads to the selection and design of optimal hydrogel structures. Using this novel approach, we show that non-trivial release curves can be obtained by generating a multitude of random structures. Strategies to generalize this approach to other systems will be discussed. [Preview Abstract] |
|
Y15.00015: What is nano to cells \& the body? Effects of shape Dennis Discher Viruses protect, target, and deliver active agents to cells and generally have quasi-spherical and filamentous morphologies. Diblock copolymer amphiphiles can assemble in water into similar shapes, namely vesicles (or polymersomes) and worm-like micelles, that prove especially robust. Controlled release polymersomes were prepared with the hydrolysable block copolymers poly(ethyleneglycol)--poly(lactic acid) (PEG-PLA) and PEG--poly(caprolactone) (PEG-PCL). When blended with non-degradable diblocks, release reflects a highly quantized process in which any given vesicle is either intact, retaining its encapsulant, or the vesicle is porated and slowly disasembing. In vivo studies demonstrate the stealthiness of polymersomes, while emerging tests of these vesicles in cell culture demonstrate great promise for controlled release of drugs and oligonucleotides into various cell types. Similar diblock copolymers are being studied as with the vesicles, although the worm micelle formers have more symmetric proportions initially. The goal is to exploit these micelles for fluid transport and delivery of the many hydrophobic drugs to cells. In vitro studies demonstrate the degradation kinetics as well as the great flexibility and targetability of these self-assembled micelles. Surprisingly, initial in vivo studies show that microns-long worm micelles circulate in the blood stream for days longer than even the longest circulating 100 nm PEGylated vesicles. [Preview Abstract] |
|
Y15.00016: The Role of Nanobiotechnology in the Study of Dystrophin and B-Dystroglycan in Membrane Stability of Aging Skeletal Muscles Ashok Vaseashta, Olivia Boskovic, Allison Webb Duchene muscular dystrophy (DMD) is one of nine types of muscular dystrophy, a group of genetic degenerative diseases, primarily affecting voluntary muscles, caused by absence of dystrophin. New experiments on mice with DMD has shown that gene therapy can reverse some symptoms of the disease. The ultimate goal of gene therapy for muscle diseases is improvement of strength and function, which will require treatment in multiple muscles simultaneously. A major limitation to gene therapy until now has been that no one had found a method by which a new gene could be delivered to all the muscles of an adult animal. Recent utilization of nanotechnology to life sciences has shown exciting promises in a wide range of disciplines, showing advances in the ability to manipulate, fabricate and alter tiny subjects at the nanometer scale. In the present investigation, we have employed such techniques to study single motors such as myosin and kinesin, as well elastic proteins viz. titin and nebulin, muscle filaments, cytoskeletal filaments, and receptors in cellular membranes and cellular organelles viz. myofibril, ribosome, and chromatin. Application of AFM to images and measures the elastic properties of single monomeric and oligomeric protein, genetically engineered titin, and nebulin molecules will be presented. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700