Bulletin of the American Physical Society
APS March Meeting 2015
Volume 60, Number 1
Monday–Friday, March 2–6, 2015; San Antonio, Texas
Session S15: Bio/Nano Applications Including Sensors |
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Sponsoring Units: FIAP Chair: Ernesto E. Marinero, Purdue University Room: 008B |
Thursday, March 5, 2015 8:00AM - 8:12AM |
S15.00001: Regulation of cellular function via electromagnetic field frequency and extracellular environment: A theoretical- experimental approach Toloo Taghian, Abdul Sheikh, Daria Narmoneva, Andrei Kogan Application of external electric field (EF) as a non-pharmacological, non-invasive tool to control cell function is of great therapeutic interest. We developed a theoretical-experimental approach to investigate the biophysical mechanisms of EF interaction with cells in electrode-free physiologically-relevant configuration. Our numerical results demonstrated that EF frequency is the major parameter to control cell response to EF. Non-oscillating or low-frequency EF leads to charge accumulation on the cell surface membrane that may mediate membrane initiated cell responses. In contrast, high-frequency EF penetrates the cell membrane and reaches cell cytoplasm, where it may directly activate intracellular responses. The theoretical predictions were confirmed in our experimental studies of the effects of applied EF on vascular cell function. Results show that non-oscillating EF increases vascular endothelial growth factor (VEGF) expression while field polarity controls cell adhesion rate. High-frequency, but not low frequency, EF provides differential regulation of cytoplasmic focal adhesion kinase and VEGF expression depending on the substrate, with increased expression in cells cultured on RGD-rich synthetic hydrogels, and decreased expression for matrigel culture. [Preview Abstract] |
Thursday, March 5, 2015 8:12AM - 8:24AM |
S15.00002: Tunnel-Current based Single-Molecule Detection Method of Biopolymer Identification Takahito Ohshiro, Makusu Tsutsui, Kazumichi Yokota, Masateru Taniguchi We have been proposed a tunneling-current based identification as a single-molecule biopolymer sequencing. This methodology is based on sequentially reading the tunneling-current across individual single-biopolymer in the sequence, resulting in a high-speed electrical discrimination of the individual nucleotides. In this study, we report on a read of nucleotide sequence by the transverse electron transport through nanogap-electrode. We measured the extent of the electron-tunneling by using nanofabricated, mechanically controllable break junction, and determined the conductance values for deoxyribo/ribo- nucleoside monophosphates. When the molecules passed between the nanoelectrodes separated by a sub-nanometer gap, the tunneling-current through the molecules was increased, relative to that in the absence of molecules. The current intensity is found to be closely related to the individual molecular energy level. We also applied this method to base-typing in oligonucleotides. Based on the electrical conductivity for single-nucleotides, we read the fragment of sample nucleotide passing through the sensing electrode. On the basis of a reconstruction of the read fragment sequences, we successfully determined a sample nucleotide sequence. [Preview Abstract] |
Thursday, March 5, 2015 8:24AM - 8:36AM |
S15.00003: Multiplexed microfluidic quantification of proteins in serum Nitin Rajan, Sukumar Rajauria, Andrew Cleland Rapid and low cost immunoassays targeting proteins in blood or other bodily fluids are highly sought after for point-of-care devices and early screening of patients. Immunoturbidimetric assays utilize latex particles functionalized with antibodies, with particle aggregation in the presence of the analyte detected by a change in absorbance. Using a high throughput micro-fluidic particle analyzer based solely on electrical signals (resistive pulse sensing), we are able to accurately quantify the degree of aggregation by analyzing the changes in the particle size distribution. Thus we study the aggregation of streptavidin (SAv) coated beads in the presence of biotinylated bovine serum albumin as a proof-of-principle assay and extract the binding capacity of the SAv beads from the dose-response curve. We also use our aggregation measurement platform to characterize a commercial C-reactive protein (CRP) immunoturbidimetric assay (hsCRP, Diazyme Inc.). We obtain a linear calibration curve as well as a better limit of detection of CRP than that obtained by absorbance measurements. By using different bead sizes functionalized with different antibodies, multiplexed analyte detection is also possible. We demonstrate this by combining the commercial anti-CRP functionalized beads (0.4 microns) with biotin coated beads (1.0 microns), and carry out the simultaneous detection of SAv and CRP in a single sample. [Preview Abstract] |
Thursday, March 5, 2015 8:36AM - 8:48AM |
S15.00004: ABSTRACT WITHDRAWN |
Thursday, March 5, 2015 8:48AM - 9:00AM |
S15.00005: Self-Assembled DNA Structures for Molecular Force Measurement: A Magnetically Actuated Approach M. Armstrong, S. Lauback, C. Miller, C. Peace, C. Castro, R. Sooryakumar Understanding molecular forces is important to comprehend many of the underlying properties of molecular machines and biological processes. The relevant forces in these cases often lie in the picoNewton range, and thus experiments on individual biomolecules must integrate techniques capable of measuring such forces. A mechanical system to measure molecular forces associated with interacting DNA strands is being developed by using self-assembled DNA nanostructures and super-paramagnetic beads. The DNA nanostructure consists of single-stranded DNA molecules which can be folded into a precise compact geometry using hundreds of short oligonucleotides, i.e., staples, via programmed molecular self-assembly. These nanostructures can be polymerized into micron-scale filaments. By functionalizing the filament ends with bispecific conjugate staples, the structure can be attached to a surface as well as labeled with magnetic beads in order to apply a force on the system. External magnetic fields provide the means to maneuver and manipulate the magnetically labeled DNA structures. Preliminary findings associated with the DNA constructs and their manipulation lay the groundwork to establish real-time control of DNA nanodevices with micromanipulation. [Preview Abstract] |
Thursday, March 5, 2015 9:00AM - 9:12AM |
S15.00006: Sensitization of sub 10 nm Yb$^{3+}$-doped NaYF$_{4}$ nanoparticles with visible light through 1,2,3,4,5,6,7-heptafluro-8-hydroxyanthracene-9,10-dione chromophore Haizhou Lu, Yu Peng, Ignacio Hern\'andez, William Gillin Uniform sub 10 nm Yb$^{3+}$-doped NaYF$_{4}$ nanoparticles were prepared using a conventional hydrothermal method. Yb$^{3+}$ ions doped inside the NaYF$_{4}$ nanoparticles can be sensitized with 1,2,3,4,5,6,7-heptafluro-8-hydroxyanthracene-9,10-dione (HL), which is bounded onto the surface of the nanoparticle, through the so called ``antenna effect.'' Strong sensitization is achieved with the broad visible light excitations. The overall near infrared (NIR) emission from Yb$^{3+}$ ions is increased by a factor of 5 as a result of the broad and strong absorption of HL chromophore compared with the ytterbium's intrinsic absorption during the 980 nm regime. Interestingly, an energy migration process from Yb$^{3+}$ ions on the surface to inner-side Yb$^{3+}$ ions of doped nanoparticle is demonstrated by the time-resolved spectroscopy method. It gives a direct evidence that the local environment between the surface and center of the nanoparticle is different. We believe our material will contribute to the NIR emitters with a strong visible absorption for the bio-materials. [Preview Abstract] |
Thursday, March 5, 2015 9:12AM - 9:24AM |
S15.00007: Low cost sensing technology for type 2 diabetes monitoring Prashant Sarswat, Michael Free Alpha-hydroxybutyrate (2-hydroxybutyrate or $\alpha $-HB) is becoming more widely recognized as an important metabolic biomarker that has been shown to be highly correlated with prediabetes and other metabolic diseases. In 2012 there were 86 million Americans with prediabetes, many of whom are not aware they have prediabetes, but could be diagnosed and treated to prevent type 2 diabetes if a simple, low-cost, convenient test were available. We have developed new, low-cost, accurate $\alpha $-HB detection methods that can be used for the detection and monitoring of diseases such as prediabetes, type 2 diabetes, $\beta $-cell dysfunction, and early hyperglycemia. The new sensing method utilizes a diol recognition moiety, additives and a photoinitiator to detect $\alpha $-HB at levels near 1 micro g/l in the presence of serum compounds such as lactic acid, sodium pyruvate, and glucose. The objective of this research is to improve the understanding of the interactions that enhance $\alpha $-HB detection to enable additional improvements in $\alpha $-HB detection as well as improvements in other biosensor applications. [Preview Abstract] |
Thursday, March 5, 2015 9:24AM - 9:36AM |
S15.00008: A pH-gradient induced method for wetting metal-layer embedded nanopores Venkat Balagurusamy, Gustavo Stolovitzky Solid-state nanopores made on a single layer of Silicon nitride are wet by a number of methods by different workers. Typically, they involve using some low-surface tension liquid like iso propyl alcohol for pre-wetting before filling with the electrolyte solution of interest e.g., a buffered KCl solution both sides of the chamber that partition the nanopore. These methods can also be preceded by a cleaning step which may involve either oxygen plasma or piranha treatment. However we found that these methods were not successful in wetting certain batches of nanopores drilled in a stack of Si$_{3}$N$_{4}$/SiO$_{2}$/TiN/SiO$_{2}$/TiN/SiO$_{2}$/TiN/SiO$_{2}$/Si$_{3}$N$_{4}$ layers. We found that applying buffer solutions at different pH on the two sides of the nanopore greatly accelerated the wetting process from days to few hours and resulted in nanopores with near linear I-V behavior for high salt concentration buffer solutions. We will describe this method and the results for a number of nanopores [1]. Nanopores wet with this pH gradient method translocate DNA molecules like nanopores wet by other methods mentioned here. We believe that the actual mechanism of this wetting process is influenced strongly by the pH effect on SiO$_{2}$ surface. Efforts are underway to understand the working of this wetting method by quantum computer simulation methods [2]. [1] V.S.K.Balagurusamy, US Patent 8702944 (April 2014), ``A novel nanopore device wetting method `` [2] R.Zhou, Soft matter theory/simulations group, IBM Watson Research Center, personal communication [Preview Abstract] |
Thursday, March 5, 2015 9:36AM - 9:48AM |
S15.00009: Nanoribbon field-effect transistors as direct and label-free sensors of enzyme-substrate interactions Luye Mu, Ilia Droujinine, Nitin Rajan, Sonya Sawtelle, Mark Reed The ability to measure enzyme-substrate interactions is essential in areas such as diagnostics, treatment, and biochemical screens. Many enzymatic reactions alter the pH of its environment, suggesting of a simple and direct method for detection. We show the ability of Al$_{2}$O$_{3}$-coated Si nanoribbon field-effect transistor biosensors to sensitively measure various aspects of enzyme-substrate interactions through measuring the pH \footnote{L. Mu et al., \textbf{Nano. Lett.} 14, 5315}. Urea in phosphate buffered saline (PBS) and penicillinase in PBS and urine were measured to limits of $<$200 $\mu$M and 0.02 units/mL, respectively. We also show the ability to extract accurate kinetics from the interaction of acetylcholine and its esterase. Prior work on FET sensors has been limited by the use of surface functionalization, which not only alters enzyme-substrate affinity, but also makes enzyme activity quantification difficult. Our method involves direct detection of reactions in solution without requiring alteration to the reactants, allowing us to obtain repeatable results and sensitive limits of detection. This method is a simple, inexpensive, and effective platform for detection of enzymatic reactions, and can be readily generalized to many unrelated classes of reactants. [Preview Abstract] |
Thursday, March 5, 2015 9:48AM - 10:00AM |
S15.00010: ToF-SIMS Characterization of Biocompatible Silk/Polypyrrole Electromechanical Actuators Nathan Bradshaw, Sean Severt, Zhaoying Wang, Carly Klemke, Jesse Larson, Zihua Zhu, Amanda Murphy, Janelle Leger Materials capable of controlled movements that can also interface with biological environments are highly sought after for biomedical devices such as valves, blood vessel sutures, cochlear implants and controlled drug release devices. Recently we have reported the synthesis of films composed of a conductive interpenetrating network of the biopolymer silk fibroin and poly(pyrrole). These silk-PPy composites function as bilayer electromechanical actuators in a biologically-relevant environment, can be actuated repeatedly, and are able to generate forces comparable with natural muscle (\textgreater 0.1 MPa), making them an ideal candidate for interfacing with biological tissues. Here, time of flight secondary ion mass spectrometry was used to investigate the migration of ions in the devices during actuation. These findings will be discussed in the context of the actuation mechanism and opportunities for further improvements in device stability and performance. [Preview Abstract] |
Thursday, March 5, 2015 10:00AM - 10:12AM |
S15.00011: Biocompatible Silk-Poly(Pyrrole) Composite Trilayer Electromechanical Actuators Carly Klemke, Nathan Bradshaw, Jesse Larson, Sean Severt, Nicholas Ostrovsky-Snider, Amanda Murphy, Janelle Leger Biocompatible materials capable of controlled actuation are in high demand for use in biomedical applications such as dynamic tissue scaffolding, valves, and steerable surgical tools. Conducting polymers (CPs) have some desirable traits for use as an actuator, such as the ability to operate in biologically relevant fluids and responsiveness to low voltages. However CPs alone are limited due to their brittle nature and poor solubility. Recently we have shown that a composite material of silk and the CP poly(pyrrole) (PPy) shows promising characteristics as an actuator; it is mechanically robust as well as fully biocompatible. Initial proof-of-concept experiments demonstrated that these composites bend under an applied voltage (or current) using a simple bilayer device. Here we present the development of a trilayer device, composed of two conductive layers separated by an insulating silk layer. This configuration has twice the active surface area as a bilayer, potentially increasing the amount of mechanical motion per volt applied. We will discuss the fabrication and characterization of these devices, as well as their performance and future applications of this technology. [Preview Abstract] |
Thursday, March 5, 2015 10:12AM - 10:24AM |
S15.00012: Developing a nanoscale pressure sensor utilizing the Plasmon Ruler Alex Taylor, David Carroll We demonstrate a novel method for detecting pressure by utilizing the Plasmon Ruler; the effect by which the frequency of light scattered by a nanoparticle (NP) is red shifted when brought into close proximity with another NP. This distance dependent phenomenon is leveraged by a film/NP architecture, wherein silver NPs are suspended above a silver film by a polymer spacing layer. As the fluid pressure above the rigid substrate is increased, the polymer layer is compressed and the NP height is decreased, leading to a measurable redshift in the plasmon resonance frequency. Thus, by factoring in the strength of the polymer film's restoring force we can determine the pressure being applied. These devices were constructed onto fiber optic wires, which allow us to probe the device using the evanescent field from light inside the glass core. This naturally leads to \textit{in vivo} medical applications, such as inter-compartment or inter-cranial pressure sensing via the inserted fiber optic probe. [Preview Abstract] |
Thursday, March 5, 2015 10:24AM - 10:36AM |
S15.00013: Highly Selective and Sensitive Detection of Acetylcholine Using Receptor-Modified Single-Walled Carbon Nanotube Sensors Shihong Xu, Byeongju Kim, Hyun Seok Song, Hye Jun Jin, Eun Jin Park, Sang Hun Lee, Byung Yang Lee, Tai Hyun Park, Seunghun Hong Acetylcholine (ACh) is a neurotransmitter in a human central nervous system and is related to various neural functions such as memory, learning and muscle contractions. Dysfunctional ACh regulations in a brain can induce several neuropsychiatric diseases such as Alzheimer's disease, Parkinson's disease and myasthenia gravis. In researching such diseases, it is important to measure the concentration of ACh in the extracellular fluid of the brain. Herein, we developed a highly sensitive and selective ACh sensor based on single-walled carbon nanotube-field effect transistors (swCNT-FETs). In our work, M1 mAChR protein, an ACh receptor, was expressed in E.coli and coated on swCNT-FETs with lipid membranes. Here, the binding of ACh onto the receptors could be detected by monitoring the change of electrical currents in the underlying swCNT-FETs, allowing the real-time detection of ACh at a 100 pM concentration. Furthermore, our sensor could selectively detect ACh from other neurotransmitters. This is the first report of the real-time sensing of ACh utilizing specific binding between the ACh and M1 mAChR, and it may lead to breakthroughs in various biomedical applications such as drug screening and disease diagnosis. [Preview Abstract] |
Thursday, March 5, 2015 10:36AM - 10:48AM |
S15.00014: Nanovesicle-Carbon Nanotube Hybrid Structures Mimicking Mammalian Pain Sensory System Young Tak Cho, Hye Jun Jin, Jeong Mi An, Juhun Park, Seok Jun Moon, Seunghun Hong We developed a ``chemical-pain sensor'' based on a single-walled carbon nanotube-based field effect transistor (SWNT-FET) functionalized with rat pain sensory receptor, rat transient receptor potential vanilloid 1 (rTRPV1) mimicking a mammalian pain sensory system. The sensor can selectively detect chemical pain stimuli such as capsaicin and resiniferatoxin with a sensitivity of a 1 pM detection limit. Since this sensor allows one to quantitatively measure the concentration of chemical pain stimuli just like animal sensory systems, it can be used for various practical applications such as food screening. In addition, TRP families including rTRPV1 protein used for the sensor are now suggested as potential drug targets related to nerve and circulation disorders. Thus, the capability of measuring TRP responses using our sensor platform should open up other applications such as drug screening and basic research related with nerve and circulation systems. [Preview Abstract] |
Thursday, March 5, 2015 10:48AM - 11:00AM |
S15.00015: Floating Electrode Sensor based on CNT-FET for the Detection of DNAs Minju Lee, Byeongju Kim, Joohyung Lee, Seon Namgung, Jeongsu Kim, Jae Yeol Park, Moon-Sook Lee, Seunghun Hong DNA sensors based on carbon nanotube (CNT) networks have been drawing much attention due to their high sensitivities. In the CNT network-based DNA sensors, the modulation of the Schottky barrier by the DNA hybridization has been known to play an important role in detecting target DNA. For such applications, many researchers have tried to enhance the sensitivity of the Schottky barrier-based sensors through various methods such as the formation of a nonsymmetrical Schottky contact or the increase of the Schottky contact area. However, these methods suffered from some limitations such as the difficulty of controlling the sensor response for applications. Here in, we developed a floating electrode-based DNA sensor with controllable responses. In this strategy, metallic floating electrodes were fabricated to form Schottky barriers between CNTs and floating electrodes. We showed that the increased number of floating electrodes could enhance the sensitivity of our sensor. We also analyzed our results based on the Langmuir isotherm theory. This efficient approach could be an important strategy to improve the sensitivity and to control the response of CNT network-based sensors. Our work should provide an important insight regarding Schottky barrier-based sensors. [Preview Abstract] |
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