Digital Commons Network^™

Recent Progress In Microrna Detection Using Integrated Electric Fields And Optical Detection Methods, Logeeshan Velmanickam, Dharmakeerthi Nawarathna

Electrical & Computer Engineering Faculty Publications

Low-cost, highly-sensitivity, and minimally invasive tests for the detection and monitoring of life-threatening diseases and disorders can reduce the worldwide disease burden. Despite a number of interdisciplinary research efforts, there are still challenges remaining to be addressed, so clinically significant amounts of relevant biomarkers in body fluids can be detected with low assay cost, high sensitivity, and speed at point-of-care settings. Although the conventional proteomic technologies have shown promise, their ability to detect all levels of disease progression from early to advanced stages is limited to a limited number of diseases. One potential avenue for early diagnosis is microRNA (miRNA). …

Identification Of Proteins Involved In Cell Membrane Permeabilization By Nanosecond Electric Pulses (Nsep), Giedre Silkuniene, Uma Mangalanathan, Alessandra Rossi, Peter A. Mollica, Andrei G. Pakhomov, Olga N. Pakhomova

Bioelectrics Publications

The study was aimed at identifying endogenous proteins which assist or impede the permeabilized state in the cell membrane disrupted by nsEP (20 or 40 pulses, 300 ns width, 7 kV/cm). We employed a LentiArray CRISPR library to generate knockouts (KOs) of 316 genes encoding for membrane proteins in U937 human monocytes stably expressing Cas9 nuclease. The extent of membrane permeabilization by nsEP was measured by the uptake of Yo-Pro-1 (YP) dye and compared to sham-exposed KOs and control cells transduced with a non-targeting (scrambled) gRNA. Only two KOs, for SCNN1A and CLCA1 genes, showed a statistically significant reduction in …

Long-Range Aceo Phenomena In Microfluidic Channel, Diganta Dutta, Keifer Smith, Xavier Palmer

Electrical & Computer Engineering Faculty Publications

Microfluidic devices are increasingly utilized in numerous industries, including that of medicine, for their abilities to pump and mix fluid at a microscale. Within these devices, microchannels paired with microelectrodes enable the mixing and transportation of ionized fluid. The ionization process charges the microchannel and manipulates the fluid with an electric field. Although complex in operation at the microscale, microchannels within microfluidic devices are easy to produce and economical. This paper uses simulations to convey helpful insights into the analysis of electrokinetic microfluidic device phenomena. The simulations in this paper use the Navier–Stokes and Poisson Nernst–Planck equations solved using COMSOL …

Ultra-Low Intensity Post-Pulse Affects Cellular Responses Caused By Nanosecond Pulsed Electric Fields, Kamal Asadipour, Carol Zhou, Vincent Yi, Stephen J. Beebe, Shu Xiao

Electrical & Computer Engineering Faculty Publications

High-intensity nanosecond pulse electric fields (nsPEF) can preferentially induce various effects, most notably regulated cell death and tumor elimination. These effects have almost exclusively been shown to be associated with nsPEF waveforms defined by pulse duration, rise time, amplitude (electric field), and pulse number. Other factors, such as low-intensity post-pulse waveform, have been completely overlooked. In this study, we show that post-pulse waveforms can alter the cell responses produced by the primary pulse waveform and can even elicit unique cellular responses, despite the primary pulse waveform being nearly identical. We employed two commonly used pulse generator designs, namely the Blumlein …

Numerical Study Of The Time-Periodic Electroosmotic Flow Of Viscoelastic Fluid Through A Short Constriction Microchannel, Jianyu Ji, Shizhi Qian, Armani Marie Parker, Xiaoyu Zhang

Mechanical & Aerospace Engineering Faculty Publications

Electroosmotic flow (EOF) is of utmost significance due to its numerous practical uses in controlling flow at micro/nanoscales. In the present study, the time-periodic EOF of a viscoelastic fluid is statistically analyzed using a short 10:1 constriction microfluidic channel joining two reservoirs on either side. The flow is modeled using the Oldroyd-B (OB) model and the Poisson-Boltzmann model. The EOF of a highly concentrated polyacrylamide (PAA) aqueous solution is investigated under the combined effects of an alternating current (AC) electric field and a direct current (DC) electric field. Power-law degradation is visible in the energy spectra of the velocity fluctuations …

Electroporation And Cell Killing By Milli- To Nanosecond Pulses And Avoiding Neuromuscular Stimulation In Cancer Ablation, Emily Gudvangen, Vitalii Kim, Vitalij Novickij, Federico Battista, Andrei G. Pakhomov

Bioelectrics Publications

Ablation therapies aim at eradication of tumors with minimal impact on surrounding healthy tissues. Conventional pulsed electric field (PEF) treatments cause pain and muscle contractions far beyond the ablation area. The ongoing quest is to identify PEF parameters efficient at ablation but not at stimulation. We measured electroporation and cell killing thresholds for 150 ns–1 ms PEF, uni- and bipolar, delivered in 10- to 300-pulse trains at up to 1 MHz rates. Monolayers of murine colon carcinoma cells exposed to PEF were stained with YO-PRO-1 dye to detect electroporation. In 2–4 h, dead cells were labeled with propidium. Electroporation and …

Editorial For The Special Issue On Micromachines For Non-Newtonian Microfluidics, Lanju Mei, Shizhi Qian

Mechanical & Aerospace Engineering Faculty Publications

In lieu of an abstract, this is an excerpt from the first page.

Microfluidics has seen a remarkable growth over the past few decades, with its extensive applications in engineering, medicine, biology, chemistry, etc [...]

Assembly Of Alumina Particles In Aqueous Suspensions Induced By High‐Frequency Ac Electric Field, James E. John, Shizhi Qian, Dipankar Ghosh

Mechanical & Aerospace Engineering Faculty Publications

The role of high-frequency alternating current (AC) electric field in the assembly of alumina particles in aqueous media was investigated. Field–particle interactions were in situ investigated for coarse and fine powder particles in very dilute suspensions. For both coarse and fine particles, AC field-induced assembly led to the formation of chains of particles within a minute, which were aligned in the field direction. However, a much finer network of particle chains evolved in fine particle suspensions. Threshold field strength for chain formation was also lower for fine particles (28 V/mm) than for coarse particles (50 V/mm), suggesting stronger interactions for …

Quadrupoles For Remote Electrostimulation Incorporating Bipolar Cancellation, Shu Xiao, Ryo Yamada, Carol Zhou

Bioelectrics Publications

Introduction: A method that utilizes nanosecond bipolar cancellation (BPC) near a quadrupole electrodes to suppress a biological response but cancels the distal BPC at the quadrupole center, i.e., cancellation of cancellation (CANCAN), may allow for a remote focused stimulation at the quadrupole center.

Objectives: The primary object of this study was to outline the requirement of the CANCAN implementation and select an effective quadrupole configuration.

Results: We have studied three quadrupole electrode configurations, a rod quadrupole, a plate quadrupole (Plate-Q), and a resistor quadrupole. The pulse shapes of electric fields include monophasic pulses, cancellation pulses, and additive pulses. The Plate-Q …

Generation Of Large-Volume High-Pressure Plasma By Spatiotemporal Control Of Space Charge, Shirshak K. Dhali

Electrical & Computer Engineering Faculty Publications

Any attempt to scale pressure and volume of nonthermal plasma usually leads to instabilities due to the formation of localized space charge. The control of the plasma is limited by the discharge geometry, type of excitation, and gas composition. This article explores the possibility of controlling the space charge in a discharge with a spatially and temporally varying electric field. It is shown that a phase-staggered sinusoidal excitation to a set of conformal azimuthal electrodes in a cylindrical geometry leads to a traveling electric field. Simulations show that in space charge dominated transport, the charged species are dispersed both in …

Editorial For The Special Issue On Micro/Nano-Chip Electrokinetics, Volume Iii, Shizhi Qian, Xiangchun Xuan

Mechanical & Aerospace Engineering Faculty Publications

No abstract provided.

Aluminum Multicharged Ion Generation From Femtosecond Laser Plasma, Md. Haider A. Shaim, Frederick Guy Wilson, Hani E. Elsayed-Ali

Electrical & Computer Engineering Faculty Publications

Aluminum multicharged ion generation from femtosecond laser ablation is studied. A Ti:sapphire laser (wavelength 800 nm, pulse width ∼100 fs, and maximum laser fluence of 7.6 J/cm²) is used. Ion yield and energy distribution of each charge state are measured. A linear relationship between the ion charge state and the equivalent acceleration energy of the individual ion species is observed and is attributed to the presence of an electric field within the plasma-vacuum boundary that accelerates the ions. The ion energy distribution follows a shifted Coulomb-Boltzmann distribution. For Al¹⁺ and Al²⁺, the ion energy distributions …

Ablation Of Myocardial Tissue With Nanosecond Pulsed Electric Fields, Fei Xie, Frency Varghese, Andrei G. Pakhomov, Iurii Semenov, Shu Xiao, Jonathan Philpott, Christian Zemlin

Bioelectrics Publications

Background

Ablation of cardiac tissue is an essential tool for the treatment of arrhythmias, particularly of atrial fibrillation, atrial flutter, and ventricular tachycardia. Current ablation technologies suffer from substantial recurrence rates, thermal side effects, and long procedure times. We demonstrate that ablation with nanosecond pulsed electric fields (nsPEFs) can potentially overcome these limitations.

Methods

We used optical mapping to monitor electrical activity in Langendorff-perfused New Zealand rabbit hearts (n = 12). We repeatedly inserted two shock electrodes, spaced 2–4 mm apart, into the ventricles (through the entire wall) and applied nanosecond pulsed electric fields (nsPEF) (5–20 kV/cm, 350 ns duration, …

Dispersion Of Cytotoxic Properties Of Multi-Walled Carbon Nanotubes Suspended In Biological Solutions With Tween 80: Their Role In Enhancing Killing Effects Of Nanosecond Pulse Electric Fields On Tumor Cell Lines, Bhargava S. Kalluri

Biological Sciences Theses & Dissertations

The objective of this study was to determine whether multi-walled carbon nanotubes (MWCNTs) suspended in the surfactant Tween 80 give an additive killing effect on tumor cells when exposed to nsPEFs. In this study, MWCNTs were suspended in DMEM and RPMI with or without T80 (surfactant). The size distribution of MWCNTs suspended in these solutions was evaluated with a Delsa™ Nano Zeta potential and sub micro particle Size Analyzer and confirmed with microscopy. The cytotoxicity of MWCNTs dispersed in different concentrations of T80 was evaluated in PANC1 (Human pancreatic cancer cell line) and Jurkat cell lines (Human T-cell lymphoblast cell …

Human Osteoblast Proliferation In Culture Following A Nanosecond Pulsed Electric Field (Nspef), Leonard Joseph Carinci Jr.

Biological Sciences Theses & Dissertations

Osteoblasts are mononucleate bone forming cells responsible for the deposition of new bone. Application of mechanical stress on bone reveals its ability to produce and release electric potentials across the cell membrane called piezoelectricity. The electric potentials produced in response to mechanical stress may have a direct correlation on osseous cells and the signaling pathways that regulate proliferation. Nanosecond pulsed electric fields (nsPEFs) are high intensity, ultrashort pulses which have the ability to maintain the integrity of the cell membrane by avoiding traditional electroporation. We delivered 8 nsPEFs (0.5 Hz) of a 25 kV/cm or 35 kV/cm electric field strength …

Bioelectric Effects Of Intense Nanosecond Pulses, Karl H. Schoenbach, Barbara Y. Hargrave, Ravindra P. Joshi, Juergen F. Kolb, Richard Nuccitelli, Christopher J. Osgood, Andrei G. Pakhomov, Michael W. Stacey, James R. Swanson, Jody A. White, Shu Xiao, Jue Zhang, Stephen J. Beebe, Peter F. Blackmore, E. Stephen Buescher

Bioelectrics Publications

Electrical models for biological cells predict that reducing the duration of applied electrical pulses to values below the charging time of the outer cell membrane (which is on the order of 100 ns for mammalian cells) causes a strong increase in the probability of electric field interactions with intracellular structures due to displacement currents. For electric field amplitudes exceeding MV/m, such pulses are also expected to allow access to the cell interior through conduction currents flowing through the permeabilized plasma membrane. In both cases, limiting the duration of the electrical pulses to nanoseconds ensures only nonthermal interactions of the electric …

Microscopic Analysis For Water Stressed By High Electric Fields In The Prebreakdown Regime, R. P. Joshi, J. Qian, K. H. Schoenbach, E. Schamiloglu

Bioelectrics Publications

Analysis of the electrical double layer at the electrode-water interface for voltages close to the breakdown point has been carried out based on a static, Monte Carlo approach. It is shown that strong dipole realignment, ion-ion correlation, and finite-size effects can greatly modify the electric fields and local permittivity (hence, leading to optical structure) at the electrode interface. Dramatic enhancements of Schottky injection, providing a source for electronic controlled breakdown, are possible. It is also shown that large pressures associated with the Maxwell stress tensor would be created at the electrode boundaries. Our results depend on the ionic density, and …

Acceleration Element For Femtosecond Electron Pulse Compression, Bao-Liang Qian, Hani E. Elsayed-Ali

Electrical & Computer Engineering Faculty Publications

An acceleration element is proposed for compressing the electron pulse duration in a femtosecond photoelectron gun. The element is a compact metal cavity with curved-shaped walls. An external voltage is applied to the cavity where a special electric field forms in such a way that the slow electrons in the electron pulse front are accelerated more than the fast electrons, and consequently the electron pulse duration will be compressed. The distribution of the electric field inside the acceleration cavity is analyzed for the geometry of the cavity. The electron dynamics in this acceleration cavity is also investigated numerically. Numerical results …

Electric Field Mapping System With Nanosecond Temporal Rosolution, F. E. Peterkin, R. Block, K. H. Schoenbach

Bioelectrics Publications

The electric field dependence of the absorption coefficient in semi‐insulating GaAs at the absorption edge was measured in a high‐voltage pulsed experiment. Pulse duration was kept below 50 ns in order to avoid thermal effects. A GaAs laser diode was used as a probe light source with wavelength varied from 902 to 911 nm. For fields up to 40 kV/cm the absorption coefficient increased from 3 to 17 cm⁻¹ at 902 nm, with smaller absolute increases evident at the longer wavelengths. Calculation from theory was consistent with this behavior. The spatial variation of the electric field was also recorded …

Temporal Development Of Electric Field Structures In Photoconductive Gaas Switches, K. H. Schoenbach, J. S. Kenney, F.E. Peterkin, R. J. Allen

Bioelectrics Publications

The temporal development of the electric field distribution in semi‐insulating GaAs photoconductive switches operated in the linear and lock‐on mode has been studied. The field structure was obtained by recording a change in the absorption pattern of the switch due to the Franz–Keldysh effect at a wavelength near the band edge of GaAs. In the linear mode, a high field layer develops at the cathode contact after laser activation. With increasing applied voltage, domainlike structures become visible in the anode region and the switch transits into the lock‐on state, a permanent filamentary electrical discharge. Calibration measurements show the field intensity …

Electric Field Induced Emission As A Diagnostic Tool For Measurement Of Local Electric Field Strengths, A. N. Dharamsi, K. H. Schoenbach

Bioelectrics Publications

The phenomenon of electric field induced (EFI) emission is examined in several diatomic and polyatomic molecules. The possibility of using this phenomenon as a diagnostic tool to measure, nonintrusively, the strength and direction of local electric fields in plasmas is discussed. An estimate of the EFI signal emitted in a typical application plasma is given. This yields a lower bound on the detector sensitivity necessary to exploit EFI emission in practical applications. It is concluded that, at present, the EFI signal could be measured by some very sensitive infrared detection schemes available. Current progress in infrared detector technology, if maintained, …