The Effect Of Surface Modification Of Aligned Poly-L-Lactic Acid Electrospun Fibers On Fiber Degradation And Neurite Extension,
2015
Missouri University of Science and Technology
The Effect Of Surface Modification Of Aligned Poly-L-Lactic Acid Electrospun Fibers On Fiber Degradation And Neurite Extension, Nicholas J. Schaub, Clémentine Le Beux, Jianjun Miao, Robert J. Linhardt, Johan G. Alauzun, Danielle Laurencin, Ryan J. Gilbert
Chemical and Biochemical Engineering Faculty Research & Creative Works
The surface of aligned, electro spun poly-L-lactic acid (PLLA) fibers was chemically modified to determine if surface chemistry and hydrophilicity could improve neurite extension from chick dorsal root ganglia. Specifically, diethylenetriamine (DTA, for amine functionalization), 2-(2-aminoethoxy) ethanol (AEO, for alcohol functionalization), or GRGDS (cell adhesion peptide) were covalently attached to the surface of electro spun fibers. Water contact angle measurements revealed that surface modification of electro spun fibers significantly improved fiber hydrophilicity compared to unmodified fibers (p < 0.05). Scanning electron microscopy (SEM) of fibers revealed that surface modification changed fiber topography modestly, with DTA modified fibers displaying the roughest surface structure. Degradation of chemically modified fibers revealed no change in fiber diameter in any group over a period of seven days. Unexpectedly, neurites from chick DRG were longest on fibers without surface modification (1651 ± 488 μm) and fibers containing GRGDS (1560 ± 107 μm). Fibers modified with oxygen plasma (1240 ± 143 μm) or DTA (1118 ± 82 μm) produced shorter neurites than the GRGDS or unmodified fibers but were not statistically shorter than unmodified and GRGDS modified fibers. Fibers modified with AEO (844 ± 151 μm) were significantly shorter than unmodified and GRGDS modified fibers (p< 0.05). Based on these results, we conclude that fiber hydrophilic enhancement alone on electro spun PLLA fibers does not enhance neurite outgrowth. Further work must be conducted to better understand why neurite extension was not improved on more hydrophilic fibers, but the results presented here do not recommend hydrophilic surface modification for the purpose of improving neurite extension unless a bioactive ligand is used.
Spectroscopic Separation Of Čerenkov Radiation In High-Resolution Radiation Fiber Dosimeters,
2015
University of Pennsylvania
Spectroscopic Separation Of Čerenkov Radiation In High-Resolution Radiation Fiber Dosimeters, Arash Darafsheh, Rongxiao Zhang, Stephen Chad Kanick, Brian W. Pogue, Jarod C. Finlay
Dartmouth Scholarship
We have investigated Čerenkov radiation generated in phosphor-based optical fiber dosimeters irradiated with clinical electron beams. We fabricated two high-spatial resolution fiber-optic probes, with 200 and 400 μm core diameters, composed of terbium-based phosphor tips. A generalizable spectroscopic method was used to separate Čerenkov radiation from the transmitted signal by the fiber based on the assumption that the recorded signal is a linear superposition of two basis spectra: characteristic luminescence of the phosphor medium and Čerenkov radiation. We performed Monte Carlo simulations of the Čerenkov radiation generated in the fiber and found a strong dependence of the recorded Čerenkov …
Review Of Fluorescence Guided Surgery Visualization And Overlay Techniques,
2015
Dartmouth College
Review Of Fluorescence Guided Surgery Visualization And Overlay Techniques, Jonathan T. Elliott, Alisha V. Dsouza, Scott C. Davis, Jonathan D. Olson, Keith Paulsen, David Roberts, Brian Pogue
Dartmouth Scholarship
In fluorescence guided surgery, data visualization represents a critical step between signal capture and display needed for clinical decisions informed by that signal. The diversity of methods for displaying surgical images are reviewed, and a particular focus is placed on electronically detected and visualized signals, as required for near-infrared or low concentration tracers. Factors driving the choices such as human perception, the need for rapid decision making in a surgical environment, and biases induced by display choices are outlined. Five practical suggestions are outlined for optimal display orientation, color map, transparency/alpha function, dynamic range compression, and color perception check.
Towards Continuous Aqueous Two-Phase Extraction (Catpe),
2015
Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA
Towards Continuous Aqueous Two-Phase Extraction (Catpe), Bettina Bommarius, Andres Bommarius, Irene Kaplanow, Julianne Merz, Gerhard Schembecker
Integrated Continuous Biomanufacturing II
Aqueous Two-Phase Extraction (ATPE) in mixer-settlers offers a gentle and biocompatible environment to separate proteins from complex mixtures. We have developed an aqueous two-phase system with inexpensive and biocompatible PEG 1500 or 4000 and ammonium citrate. We have purified several dehydrogenases [1] to near homogeneity after forward extraction into a PEG-heavy top phase at pH > 9 and back extraction into a bottom phase at pH 4-6; in selected cases, we were able to obtain pure protein in the bottom phase without forward extraction into the top phase. We have scaled up the PEG 1500/4000-ammonium citrate to a 5-10 L scale, …
Characterization Of Electrophorectic Separations On A Cellulose Paper-Microfluidic Chip,
2015
California Polytechnic State University, San Luis Obispo
Characterization Of Electrophorectic Separations On A Cellulose Paper-Microfluidic Chip, Kyle Robert Fast
Master's Theses
The purpose of this thesis project is to demonstrate the ability to utilize electrophoresis in a cellulose paper microfluidic chip to manipulate charged particles. Materials were selected and a manufacturing protocol was created to successfully apply the electric field onto the paper chip. Experiments were performed to characterize the separation rates for charged, colorimetric dye, Orange G in the membrane as a function of an applied electric field, dye concentration, and distance traveled. The experiments confirmed that the electric field can be applied to the chip and particle separation rates were characterized. Next, the determined rates results were used to …
The Role Of Biological Fluid And Dynamic Flow In The Behavior And Cellular Interactions Of Gold Nanoparticles,
2015
University of Dayton
The Role Of Biological Fluid And Dynamic Flow In The Behavior And Cellular Interactions Of Gold Nanoparticles, Emily K. Breitner, Saber M. Hussain, Kristen K. Comfort
Chemical and Materials Engineering Faculty Publications
Background: Due to their distinctive physicochemical properties, nanoparticles (NPs) have proven to be extremely advantageous for product and application development, but are also capable of inducing detrimental outcomes in biological systems. Standard in vitro methodologies are currently the primary means for evaluating NP safety, as vast quantities of particles exist that require appraisal. However, cell-based models are plagued by the fact that they are not representative of complex physiological systems. The need for a more accurate exposure model is highlighted by the fact that NP behavior and subsequent bioresponses are highly dependent upon their surroundings. Therefore, standard in vitro models …
Investigation Of Bovine Serum Albumin (Bsa)
Attachment Onto Self-Assembled Monolayers
(Sams) Using Combinatorial Quartz Crystal
Microbalance With Dissipation (Qcm-D) And
Spectroscopic Ellipsometry (Se),
2015
University of Nebraska-Lincoln
Investigation Of Bovine Serum Albumin (Bsa) Attachment Onto Self-Assembled Monolayers (Sams) Using Combinatorial Quartz Crystal Microbalance With Dissipation (Qcm-D) And Spectroscopic Ellipsometry (Se), Hanh T.M. Phan, Shannon L. Bartelt-Hunt, Keith B. Rodenhausen, Mathias Schubert, Jason C. Bartz
Department of Civil and Environmental Engineering: Faculty Publications
Understanding protein adsorption kinetics to surfaces is of importance for various environmental and biomedical applications. Adsorption of bovine serum albumin to various selfassembled monolayer surfaces including neutral and charged hydrophilic and hydrophobic surfaces was investigated using in-situ combinatorial quartz crystal microbalance with dissipation and spectroscopic ellipsometry. Adsorption of bovine serum albumin varied as a function of surface properties, bovine serum albumin concentration and pH value. Charged surfaces exhibited a greater quantity of bovine serum albumin adsorption, a larger bovine serum albumin layer thickness, and increased density of bovine serum albumin protein compared to neutral surfaces at neutral pH value. The …
Opportunities To Identify Unmet Needs Outside Of The Operating Room,
2015
Marquette University
Opportunities To Identify Unmet Needs Outside Of The Operating Room, Jay R. Goldberg
Biomedical Engineering Faculty Research and Publications
The ability to identify unmet needs and new product opportunities is an important skill for biomedical engineering students planning a career in the medical device industry. Most biomedical engineering graduates will work in industry where many projects will not be defined for them. They will need to work with physicians, surgeons, nurses, clinical engineers, and other users of medical technology to identify problems and unmet needs and will work closely with marketing, sales, and other personnel to identify new product development opportunities. Students will be better prepared for careers involving the development of new medical devices if they are able …
Magnetic Ngf-Releasing Plla/Iron Oxide Nanoparticles Direct Extending Neurites And Preferentially Guide Neurites Along Aligned Electrospun Microfibers,
2015
Missouri University of Science and Technology
Magnetic Ngf-Releasing Plla/Iron Oxide Nanoparticles Direct Extending Neurites And Preferentially Guide Neurites Along Aligned Electrospun Microfibers, Jonathan M. Zuidema, Christina Provenza, Tyler Caliendo, Silvio Dutz, Ryan J. Gilbert
Chemical and Biochemical Engineering Faculty Research & Creative Works
Nerve growth factor releasing composite nanoparticles (NGF-cNPs) were developed to direct the extension of neurite outgrowth from dorsal root ganglia (DRG). Iron oxide magnetic nanoparticles were incorporated into poly-l-lactic acid (PLLA) nanoparticles in order to position the NGF-cNPs in a culture dish. Neurites growing from DRG extended toward the NGF released from the NGF-cNPs. DRG were then cultured on aligned PLLA microfibers in the presence of NGF-cNPs, and these biomaterials combined to align DRG neurite extension along one axis and preferentially toward the NGF-cNPs. This combinatorial biomaterial approach shows promise as a strategy to direct the extension of regenerating neurites.
Direct Regularization From Co-Registered Anatomical Images For Mri-Guided Near-Infrared Spectral Tomographic Image Reconstruction,
2015
Dartmouth College
Direct Regularization From Co-Registered Anatomical Images For Mri-Guided Near-Infrared Spectral Tomographic Image Reconstruction, Limin Zhang, Yan Zhao, Shudong Jiang, Brian W. Pogue, Keith Paulsen
Dartmouth Scholarship
Combining anatomical information from high resolution imaging modalities to guide near-infrared spectral tomography (NIRST) is an efficient strategy for improving the quality of the reconstructed spectral images. A new approach for incorporating image information directly into the inversion matrix regularization was examined using Direct Regularization from Images (DRI), which encodes the gray-scale data into the NIRST image reconstruction problem. This process has the benefit of eliminating user intervention such as image segmentation of distinct regions. Specifically, the Dynamic Contrast Enhanced Magnetic Resonance (DCE-MR) image intensity value differences within the anatomical image were used to implement an exponentially-weighted regularization function between …
Impaired Regulation Post-Stroke Of Motor Unit Firing Behavior During Volitional Relaxation Of Knee Extensor Torque Assessed Using High Density Surface Emg Decomposition,
2015
Marquette University
Impaired Regulation Post-Stroke Of Motor Unit Firing Behavior During Volitional Relaxation Of Knee Extensor Torque Assessed Using High Density Surface Emg Decomposition, Spencer A. Murphy, Reivian Berrios, P. Andrew Nelson, Francesco Negro, Dario Farina, Brian D. Schmit, Allison S. Hyngstrom
Physical Therapy Faculty Research and Publications
The purpose of this study was to use high density surface EMG recordings to quantify stroke-related abnormalities in motor unit firing behavior during repeated sub-maximal knee extensor contractions. A high density surface EMG system (sEMG) was used to record and extract single motor unit firing behavior in the vastus lateralis muscle of 6 individuals with chronic stroke and 8 controls during repeated sub-maximal isometric knee extension contractions. Paretic motor unit firing rates were increased with subsequent contractions (6.19±0.35 pps vs 7.89±0.66 pps, P
Experimental Investigation Of Mechanical And Thermal Properties Of Silica Nanoparticle-Reinforced Poly(Acrylamide) Nanocomposite Hydrogels,
2015
Santa Clara University
Experimental Investigation Of Mechanical And Thermal Properties Of Silica Nanoparticle-Reinforced Poly(Acrylamide) Nanocomposite Hydrogels, Josergio Zaragoza, Nasim Babhadiashar, Victor O’Brien, Andrew Chang, Matthew Blanco, Aitor Zabalegui, Hohyun Lee, Prashanth Asuri
Bioengineering
Current studies investigating properties of nanoparticle-reinforced polymers have shown that nanocomposites often exhibit improved properties compared to neat polymers. However, over two decades of research, using both experimental studies and modeling analyses, has not fully elucidated the mechanistic underpinnings behind these enhancements. Moreover, few studies have focused on developing an understanding among two or more polymer properties affected by incorporation of nanomaterials. In our study, we investigated the elastic and thermal properties of poly(acrylamide) hydrogels containing silica nanoparticles. Both nanoparticle concentration and size affected hydrogel properties, with similar trends in enhancements observed for elastic modulus and thermal diffusivity. We also …
Raman Spectroscopy Applied To The Noninvasive Detection Of Monosodium Urate Crystal Deposits,
2015
Missouri University of Science and Technology
Raman Spectroscopy Applied To The Noninvasive Detection Of Monosodium Urate Crystal Deposits, Declan J. Curran, Laurence Rubin, Mark R. Towler
Chemical and Biochemical Engineering Faculty Research & Creative Works
An off-the-shelf Raman Spectrometer (RS) was used to noninvasively determine the presence of monosodium urate (MSU) crystals on the metatarsophalangeal joint (MTPJ) of a single gout sufferer. The spectrum sourced from the clinically diagnosed gout sufferer was compared to that sourced from an age-matched healthy subject scanned using the same protocol. Minimal signal processing was conducted on both spectra. Peaks characteristic of MSU crystals were evident on the spectrum sourced from the gout sufferer and not on the spectrum from the healthy control.
Stretch‐Induced Increase In Cardiac Contractility Is Independent Of Myocyte Ca2+ While Block Of Stretch Channels By Streptomycin Improves Contractility After Ischemic Stunning,
2015
Medical College of Wisconsin
Stretch‐Induced Increase In Cardiac Contractility Is Independent Of Myocyte Ca2+ While Block Of Stretch Channels By Streptomycin Improves Contractility After Ischemic Stunning, Samhita S. Rhodes, Amadou Ks Camara, Mohammed Aldakkak, James S. Heisner, David F. Stowe
Biomedical Engineering Faculty Research and Publications
Stretching the cardiac left ventricle (LV) enhances contractility but its effect on myoplasmic [Ca2+] is controversial. We measured LV pressure (LVP) and [Ca2+] as a function of intra-LV stretch in guinea pig intact hearts before and after 15 min global stunning ± perfusion with streptomycin (STM), a stretch activated channel blocker. LV wall [Ca2+] was measured by indo-1 fluorescence and LVP by a saline-filled latex balloon inflated in 50 μL steps to stretch the LV. We implemented a mathematical model to interpret crossbridge dynamics and myofilament Ca2+ responsiveness from the instantaneous relationship between …
Spontaneous Firing Of Sensory Neurons Modulates The Gain In The Downstream Circuit Of A Simple Olfactory System,
2015
Washington University in St. Louis
Spontaneous Firing Of Sensory Neurons Modulates The Gain In The Downstream Circuit Of A Simple Olfactory System, Matthew O'Neill
McKelvey School of Engineering Graduate Student Theses & Dissertations
In locusts and other insects, odorants are transduced into electrical signal by the olfactory receptor neurons and transmitted to central circuits for further processing. Previous studies have shown that exogenous variables (e.g., flow rates, humidity, temperature, odor mixtures, etc.) can influence the responses of the sensory neurons and therefore modulate the central circuits. However, how the sensory neuron activity is manipulated to achieve adaptive gain control in the following circuit is yet to be understood. It is possible that the magnitude of the stimulus-evoked response in the receptor neurons, their spontaneous activity, or both of these factors can change how …
An Implantable Device To Regulate Urination Through Deep Brain Stimulation,
2015
Purdue University
An Implantable Device To Regulate Urination Through Deep Brain Stimulation, Jesse E. Bucksot, Muhammad A. Arafat, Pedro Irazoqui
The Summer Undergraduate Research Fellowship (SURF) Symposium
Urinary Incontinence (UI) is a disease in which patients lose control of their bladder. It is particularly common in elderly women having a prevalence of as much as 30% to 50% [1]. Many of these patients are left without successful treatment. A recent study has shown a new option for treatment that consists of deep brain stimulation (DBS) at a site known as the periaqueductal gray (PAG) [2, 3]. To test the effectiveness of this treatment, chronic stimulation of the PAG should be used in animals to see if it can reliably prevent micturition in the long term. A device …
Simulating Low-Frequency Sonic Pulsations To Achieve Thrombolysis,
2015
Purdue University
Simulating Low-Frequency Sonic Pulsations To Achieve Thrombolysis, Joseph C. Muskat, Matthew C. Pharris, Charles F. Babbs
The Summer Undergraduate Research Fellowship (SURF) Symposium
Cardiovascular thrombosis may result in critical ischemia to a range of anatomical regions, constituting a leading cause of death in the United States. Current invasive treatments for such arterial blockages often yield blood clot recurrence, resulting in repeated hospitalization of patients. This research aims to show how internally introduced pressure oscillations may be used to initiate thrombolysis. We present a novel computational model for determining the resonant frequency and corresponding deformation of an idealized thrombus. Sinusoidal pressure differences across the thrombus induce axial displacements of frequency dependent amplitude. The maximum peak displacement occurs at a resonant frequency of 73 Hz …
Cold Atmospheric Plasma: An Inside Look Through Optical Diagnostics For Biomedical Applications,
2015
Villanova University
Cold Atmospheric Plasma: An Inside Look Through Optical Diagnostics For Biomedical Applications, Liesl Krause, Ahmed Hassanein, Prasoon Diwakar
The Summer Undergraduate Research Fellowship (SURF) Symposium
An emerging technology for medical applications is cold atmospheric plasma (CAP). CAP is generated using various gasses in a “pen” to create room temperature plasma and then carry the effluents and species. Success has been shown when cold atmospheric plasma is applied to oncology treatments, accelerated wound healing, pathogen disinfection, and various material-changing effects. However, the mechanisms behind these effects are still speculative. This study uses multiple diagnostic techniques including fast photography, two wavelength emission spectroscopy and optical emission spectroscopy to characterize the plasma properties and eventually further test the plasma’s interaction with biological samples. The plume dynamics are observed …
An Investigation Of The Applicability Of Sugar And Wax Valves For Rapid Molecular Diagnostics,
2015
Purdue University
An Investigation Of The Applicability Of Sugar And Wax Valves For Rapid Molecular Diagnostics, Rui Shen, Jacqueline C. Linnes
The Summer Undergraduate Research Fellowship (SURF) Symposium
Paper-based Loop-mediated Isothermal Amplification (LAMP) of nucleic acids is a low-cost molecular diagnostic method to detect biological pathogens and has been successfully combined with lateral flow devices. This invention is a low-cost visual detection technique of various disease. However, existing assays require multiple user-activated steps and are relatively complicated to use at the point of care due to steps like the heating process. This project aimed to investigate an ideal valve for integrating LAMP onto the lateral flow assay. An ideal valve needs to be able to stop the fluid flow for 20-60 minutes under 65 degree to complete the …
Indentation Probing Of In Vitro Bovine Articular Cartilage: Effects On Chondrocyte Viability And Tissue Biomechanics,
2015
Purdue University
Indentation Probing Of In Vitro Bovine Articular Cartilage: Effects On Chondrocyte Viability And Tissue Biomechanics, Pablo F. Argote, Alan Poon, Xin Xu Ph.D, Corey P. Neu Ph.D.
The Summer Undergraduate Research Fellowship (SURF) Symposium
Osteoarthritis (OA) consists of a degenerative disease on articular cartilage, which is prone to excessive mechanical loading and frictional resistance that leads to the wear and tear of the tissue. These factors result in the progressive and incurable disease that affects millions of people worldwide. The goal is to characterize chondrocyte viability and the in vitro biomechanical properties of articular cartilage in two confined indentation studies. One study looks at the chondrocyte viability over seven days. The second compares the immediate effects of strain rates on chondrocyte viability and tissue biomechanics. Bovine cartilage explants are harvested, cultured, and then 40% …
