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Biomedical Engineering and Bioengineering Commons™

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Biophysics

2020

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Articles 1 - 13 of 13

Full-Text Articles in Biomedical Engineering and Bioengineering

Controlled Membrane Remodeling By Nanospheres And Nanorods: Experiments Targeting The Design Principles For Membrane-Based Materials, Sarah Zuraw-Weston Dec 2020

Controlled Membrane Remodeling By Nanospheres And Nanorods: Experiments Targeting The Design Principles For Membrane-Based Materials, Sarah Zuraw-Weston

Doctoral Dissertations

In this thesis we explore two experimental systems probing the interactions of nanoparticles with lipid bilayer membranes. Inspired by the ability of cell membranes to alter their shape in response to bound particles, we report two experimental studies: one of nanospheres the other of long, slender nano-rods binding to lipid bilayer vesicles and altering the membrane shape. Our work illuminates the role of particle geometry, particle concentration, adhesion strength and membrane tension in how membrane morphology is determined. We combine giant unilamellar vesicles with oppositely charged nanoparticles, carefully tuning adhesion strength, membrane tension and particle concentration. In the case of …

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Micro-Physiological Models To Mimic Mucosal Barrier Complexity Of The Human Intestine In Vitro, Abhinav Sharma Dec 2020

Micro-Physiological Models To Mimic Mucosal Barrier Complexity Of The Human Intestine In Vitro, Abhinav Sharma

Doctoral Dissertations

The mucosal barrier in the intestine is vital to maintain selective absorption of nutrients while protecting internal tissues and maintaining symbiotic relationship with luminal microbiota. This bio-barrier consists of a cellular epithelial barrier and an acellular mucus barrier. Secreted mucus regulates barrier function via in situ biochemical and biophysical interaction with luminal content that continually evolves during digestion and absorption. Increasing evidence suggests that a mucus barrier is indispensable to maintain homeostasis in the gastrointestinal tract. However, the importance of mucus barrier is largely underrated for in vitro mucosal tissue modeling. The major gap is the lack of experimental material …

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Biomechanical And Biophysical Properties Of Breast Cancer Cells Under Varying Glycemic Regimens, Diganta Dutta, Xavier-Lewis Palmer, Jose Ortega-Rodas, Vasundhara Balraj, Indrani Ghosh Dastider, Surabhi Chandra Nov 2020

Biomechanical And Biophysical Properties Of Breast Cancer Cells Under Varying Glycemic Regimens, Diganta Dutta, Xavier-Lewis Palmer, Jose Ortega-Rodas, Vasundhara Balraj, Indrani Ghosh Dastider, Surabhi Chandra

Electrical & Computer Engineering Faculty Publications

Diabetes accelerates cancer cell proliferation and metastasis, particularly for cancers of the pancreas, liver, breast, colon, and skin. While pathways linking the 2 disease conditions have been explored extensively, there is a lack of information on whether there could be cytoarchitectural changes induced by glucose which predispose cancer cells to aggressive phenotypes. It was thus hypothesized that exposure to diabetes/high glucose alters the biomechanical and biophysical properties of cancer cells more than the normal cells, which aids in advancing the cancer. For this study, atomic force microscopy indentation was used through microscale probing of multiple human breast cancer cells (MCF-7, …

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Axonal Blockage With Microscopic Magnetic Stimulation, Hui Ye Oct 2020

Axonal Blockage With Microscopic Magnetic Stimulation, Hui Ye

Biology: Faculty Publications and Other Works

Numerous neurological dysfunctions are characterized by undesirable nerve activity. By providing reversible nerve blockage, electric stimulation with an implanted electrode holds promise in the treatment of these conditions. However, there are several limitations to its application, including poor bio-compatibility and decreased efficacy during chronic implantation. A magnetic coil of miniature size can mitigate some of these problems, by coating it with biocompatible material for chronic implantation. However, it is unknown if miniature coils could be effective in axonal blockage and, if so, what the underlying mechanisms are. Here we demonstrate that a submillimeter magnetic coil can reversibly block action potentials …

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Single‐Molecule 3d Orientation Imaging Reveals Nanoscale Compositional Heterogeneity In Lipid Membranes, Jin Lu, Hesam Mazidi, Tianben Ding, Oumeng Zhang, Matthew D. Lew Sep 2020

Single‐Molecule 3d Orientation Imaging Reveals Nanoscale Compositional Heterogeneity In Lipid Membranes, Jin Lu, Hesam Mazidi, Tianben Ding, Oumeng Zhang, Matthew D. Lew

Electrical & Systems Engineering Publications and Presentations

In soft matter, thermal energy causes molecules to continuously translate and rotate, even in crowded environments, thereby impacting the spatial organization and function of most molecular assemblies, such as lipid membranes. Directly measuring the orientation and spatial organization of large collections (>3000 molecules μm−2) of single molecules with nanoscale resolution remains elusive. In this paper, we utilize SMOLM, single‐molecule orientation localization microscopy, to directly measure the orientation spectra (3D orientation plus “wobble”) of lipophilic probes transiently bound to lipid membranes, revealing that Nile red's (NR) orientation spectra are extremely sensitive to membrane chemical composition. SMOLM images resolve …

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Validation Of Nanosecond Pulse Cancellation Using A Quadrupole Exposure System, Hollie A. Ryan Aug 2020

Validation Of Nanosecond Pulse Cancellation Using A Quadrupole Exposure System, Hollie A. Ryan

Biomedical Engineering Theses & Dissertations

Nanosecond pulsed electric fields (nsPEFs) offer a plethora of opportunities for developing integrative technologies as complements or alternatives to traditional medicine. Studies on the biological effects of nsPEFs in vitro and in vivo have revealed unique characteristics that suggest the potential for minimized risk of complications in patients, such as the ability of unipolar nsEPs to create permanent or transient pores in cell membranes that trigger localized lethal or non-lethal outcomes without consequential heating. A more recent finding was that such responses could be diminished by applying a bipolar pulse instead, a phenomenon dubbed bipolar cancellation, paving the way …

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Cardiac Modelling Techniques To Predict Future Heart Function And New Biomarkers In Acute Myocardial Infarction, Sergio C. H. Dempsey Jun 2020

Cardiac Modelling Techniques To Predict Future Heart Function And New Biomarkers In Acute Myocardial Infarction, Sergio C. H. Dempsey

Electronic Thesis and Dissertation Repository

Fundamental to treatment planning for patients that have suffered myocardial infarction are predictive biomarkers and risk factors. Important among these in terms of a patient’s treatment plan or prognosis are the contractility of the damaged myofibers, final infarct volume, and poor infarct healing rate. Proposed and developed in this thesis are techniques to predict these biomarkers and risk factors using cardiac biomechanical modelling. One of the developed techniques was a CT compatible shape optimization technique which can predict the contraction force of healthy, and stunned myofibers within 6.3% and the distribution of potentially necrotic myofibers within 10% accuracy. The second …

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Phantoms To Placentas: Mr Methods For Oxygen Quantification, Kelsey Meinerz May 2020

Phantoms To Placentas: Mr Methods For Oxygen Quantification, Kelsey Meinerz

Arts & Sciences Electronic Theses and Dissertations

Molecular oxygen (O2) is vital for efficient energy production and improper oxygenation is a hallmark of disease or metabolic dysfunction. In many pathologies, knowledge of tissue oxygen levels (pO2) could aid in diagnosis and treatment planning. The gold standard for pO2 measures in tissue are implantable probes, which are invasive, require surgery for placement, and are inaccessible to certain regions of the body. Methods for determining pO2 both non-invasively and quantitatively are lacking. The slight paramagnetic nature of O2 provides opportunities to non-invasively characterize pO2 in tissue via magnetic resonance (MR) techniques. As such, O2 can be treated as a …

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Study Of The Therapeutic Effects Of Synchronization-Modulation Of The Na/K Pump On Muscle Fatigue, Jason E. Mast Apr 2020

Study Of The Therapeutic Effects Of Synchronization-Modulation Of The Na/K Pump On Muscle Fatigue, Jason E. Mast

USF Tampa Graduate Theses and Dissertations

It has been shown that by applying a specially designed oscillating external electric field to a cell membrane that the membrane's sodium/potassium pumps can be synchronized to all work at the same rate. Then by slowly increasing the electric field's frequency the pumps' turnover rate can also be increased. By increasing the pumps' turnover rate, the sodium and potassium concentration gradients can be increased, this type of stimulation is called synchronization-modulation. There are three generations of the synchronization-modulation waveform each with different utilities. In particular, the third generation of synchronization-modulation has the ability to use the energy of the external …

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Impedance Analysis Of Tissues In Nspef Treatment For Cancer Therapy, Edwin Ayobami Oshin Apr 2020

Impedance Analysis Of Tissues In Nspef Treatment For Cancer Therapy, Edwin Ayobami Oshin

Biomedical Engineering Theses & Dissertations

Nanosecond pulsed electric field (nsPEF) for cancer therapy is characterized by applications of high voltage pulses with low pulsed energy to induce non-thermal effects on tissues such as tumor ablation. It nonthermally treats tissues via electroporation. Electroporation is the increase in permeabilization of a cell membrane due to the application of high pulsed electric field. The objective of this study was to investigate the effect of nsPEF on tissue by monitoring the tissue’s impedance in real-time. Potato slices (both untreated and electroporated), and tumors extracted from female BALBc mice were studied. 100ns, 1-10kV pulses were applied to the tissues using …

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Fibration Symmetries Uncover The Building Blocks Of Biological Networks, Flaviano Morone, Ian Leifer, Hernán A. Makse Mar 2020

Fibration Symmetries Uncover The Building Blocks Of Biological Networks, Flaviano Morone, Ian Leifer, Hernán A. Makse

Publications and Research

A major ambition of systems science is to uncover the building blocks of any biological network to decipher how cellular function emerges from their interactions. Here, we introduce a graph representation of the information flow in these networks as a set of input trees, one for each node, which contains all pathways along which information can be transmitted in the network. In this representation, we find remarkable symmetries in the input trees that deconstruct the network into functional building blocks called fibers. Nodes in a fiber have isomorphic input trees and thus process equivalent dynamics and synchronize their activity. Each …

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Bubble Lab Exercise, Peter Beltramo Jan 2020

Bubble Lab Exercise, Peter Beltramo

Science and Engineering Saturday Seminars

The cell membrane is a ubiquitous component in mammalian cells which control many vital biological functions. It consists of a phospholipid bilayer with embedded protein molecules which serve to transport molecules between the interior and exterior of the cell. Understanding what makes cell membranes so important and how they function requires concepts from physics, chemistry, and of course biology, but it is difficult to learn and conceptualize the structure and function of membranes due to their nanoscopic size and dynamic nature which can’t be properly appreciated in a static textbook. This activity draws analogies between the chemistry and structure of …

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Gravity-Drawing Flexible Silicone Filaments As Fiber Optics And Model Foldamers, Katherine Snell Jan 2020

Gravity-Drawing Flexible Silicone Filaments As Fiber Optics And Model Foldamers, Katherine Snell

CMC Senior Theses

Here, we present a method of gravity-drawing polydimethylsiloxane (PDMS) silicone fibers with application as fiber optics and as model foldamers. Beginning as a viscous liquid, PDMS is cured using heat until its measured viscosity reaches 4000 mPa•s. The semi-cured elastomer is then extruded through a tube furnace to produce thin (diameters on the order of hundred micrometers) filaments with scalable lengths. PDMS is biocompatible, gas-permeable, flexible, and hydrophobic. Additionally, the PDMS surface hydrophobicity can be modified via UV exposure, O2 plasma, and corona discharge. We demonstrate the patternibility (i.e patterns of hydrophobicity) of PDMS fibers, adding complexity to potential foldamer …

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