Open Access. Powered by Scholars. Published by Universities.®

Biomedical Engineering and Bioengineering Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 10 of 10

Full-Text Articles in Biomedical Engineering and Bioengineering

Transfer Of Assembled Collagen Fibrils To Flexible Substrates For Mechanically Tunable Contact Guidance Cues, Juan Wang, Joseph Koelbl, Anuraag Boddupalli, Zhiqi Yao, Kaitlin M. Bratlie, Ian C. Schneider Oct 2018

Transfer Of Assembled Collagen Fibrils To Flexible Substrates For Mechanically Tunable Contact Guidance Cues, Juan Wang, Joseph Koelbl, Anuraag Boddupalli, Zhiqi Yao, Kaitlin M. Bratlie, Ian C. Schneider

Chemical and Biological Engineering Publications

Contact guidance or bidirectional migration along aligned fibers modulates many physiological and pathological processes such as wound healing and cancer invasion. Aligned 2D collagen fibrils epitaxially grown on mica substrates replicate many features of contact guidance seen in aligned 3D collagen fiber networks. However, these 2D collagen self-assembled substrates are difficult to image through, do not have known or tunable mechanical properties and cells degrade and mechanically detach collagen fibrils from the surface, leading to an inability to assess contact guidance over long times. Here, we describe the transfer of aligned collagen fibrils from mica substrates to three different functionalized ...


Treatment Of Neurodegenerative Disorders Through The Blood-Brain Barrier Using Nanocarriers, Nitya Poovaiah, Zahra Davoudi, Haisheng Peng, Benjamin Schlichtmann, Surya K. Mallapragada, Balaji Narasimhan, Qun Wang Aug 2018

Treatment Of Neurodegenerative Disorders Through The Blood-Brain Barrier Using Nanocarriers, Nitya Poovaiah, Zahra Davoudi, Haisheng Peng, Benjamin Schlichtmann, Surya K. Mallapragada, Balaji Narasimhan, Qun Wang

Chemical and Biological Engineering Publications

Neurodegenerative diseases refer to disorders of the central nervous system (CNS) that are caused by neuronal degradations, dysfunctions, or death. Alzheimer’s disease, Parkinson’s disease, and Huntington’s disease (APHD) are regarded as the three major neurodegenerative diseases. There is a vast body of literature on the causes and treatments of these neurodegenerative diseases. However, the main obstacle in developing an effective treatment strategy is the permeability of the treatment components to the blood-brain barrier (BBB). Several strategies have been developed to improve this obstruction. For example, nanomaterials facilitate drug delivery to the BBB due to their size. They ...


Chemically Modified Gellan Gum Hydrogels With Tunable Properties For Use As Tissue Engineering Scaffolds, Zihao Xu, Zhuqing Li, Shan Jiang, Kaitlin M. Bratlie Jun 2018

Chemically Modified Gellan Gum Hydrogels With Tunable Properties For Use As Tissue Engineering Scaffolds, Zihao Xu, Zhuqing Li, Shan Jiang, Kaitlin M. Bratlie

Chemical and Biological Engineering Publications

Gellan gum is a naturally occurring polymer that can cross-link in the presence of divalent cations to form biocompatible hydrogels. However, physically cross-linked gellan gum hydrogels lose their stability under physiological conditions, thus restricting the applications of these hydrogels in vivo. To improve the mechanical strength of the gels, we incorporated methacrylate into the gellan gum and chemically cross-linked the hydrogel through three polymerization methods: step growth through thiol–ene photoclick chemistry, chain-growth via photopolymerization, and mixed model in which both mechanisms were employed. Methacrylation was confirmed and quantified by proton nuclear magnetic resonance (1H NMR) and Fourier transform infrared ...


Direct Expression Of Active Human Tissue Inhibitors Of Metalloproteinases By Periplasmic Secretion In Escherichia Coli, Ki Baek Lee, Dong Hyun Nam, Jacob A. M. Nuhn, Juan Wang, Ian C. Schneider, Xin Ge Apr 2017

Direct Expression Of Active Human Tissue Inhibitors Of Metalloproteinases By Periplasmic Secretion In Escherichia Coli, Ki Baek Lee, Dong Hyun Nam, Jacob A. M. Nuhn, Juan Wang, Ian C. Schneider, Xin Ge

Chemical and Biological Engineering Publications

Background

As regulators of multifunctional metalloproteinases including MMP, ADAM and ADAMTS families, tissue inhibitors of metalloproteinases (TIMPs) play a pivotal role in extracellular matrix remodeling, which is involved in a wide variety of physiological processes. Since abnormal metalloproteinase activities are related to numerous diseases such as arthritis, cancer, atherosclerosis, and neurological disorders, TIMPs and their engineered mutants hold therapeutic potential and thus have been extensively studied. Traditional productions of functional TIMPs and their N-terminal inhibitory domains (N-TIMPs) rely on costly and time-consuming insect and mammalian cell systems, or tedious and inefficient refolding from denatured inclusion bodies. The later process is ...


Myosin Phosphorylation On Stress Fibers Predicts Contact Guidance Behavior Across Diverse Breast Cancer Cells, Juan Wang, Ian C. Schneider Mar 2017

Myosin Phosphorylation On Stress Fibers Predicts Contact Guidance Behavior Across Diverse Breast Cancer Cells, Juan Wang, Ian C. Schneider

Chemical and Biological Engineering Publications

During cancer progression the extracellular matrix is remodeled, forming aligned collagen fibers that proceed radially from the tumor, resulting in invasion. We have recently shown that different invasive breast cancer cells respond to epitaxially grown, aligned collagen fibrils differently. This article develops insight into why these cells differ in their contact guidance fidelity. Small changes in contractility or adhesion dramatically alter directional persistence on aligned collagen fibrils, while migration speed remains constant. The directionality of highly contractile and adhesive MDA-MB-231 cells can be diminished by inhibiting Rho kinase or β1 integrin binding. Inversely, the directionality of less contractile and adhesive ...


High Throughput Studies Of Cell Migration In 3d Microtissues Fabricated By A Droplet Microfluidic Chip, Xiangchen Che, Jacob A. M. Nuhn, Ian C. Schneider, Long Que Jan 2016

High Throughput Studies Of Cell Migration In 3d Microtissues Fabricated By A Droplet Microfluidic Chip, Xiangchen Che, Jacob A. M. Nuhn, Ian C. Schneider, Long Que

Chemical and Biological Engineering Publications

Arrayed three-dimensional (3D) micro-sized tissues with encapsulated cells (microtissues) have been fabricated by a droplet microfluidic chip. The extracellular matrix (ECM) is a polymerized collagen network. One or multiple breast cancer cells were embedded within the microtissues, which were stored in arrayed microchambers on the same chip without ECM droplet shrinkage over 48 h. The migration trajectory of the cells was recorded by optical microscopy. The migration speed was calculated in the range of 3–6 µm/h. Interestingly, cells in devices filled with a continuous collagen network migrated faster than those where only droplets were arrayed in the chambers ...


Synthesis And Functionalization Of Virus-Mimicking Cationic Block Copolymers With Pathogen-Associated Carbohydrates As Potential Vaccine Adjuvants, J. R. Adams, M. Goswami, N. L.B. Pohl, Surya K. Mallapragada Mar 2014

Synthesis And Functionalization Of Virus-Mimicking Cationic Block Copolymers With Pathogen-Associated Carbohydrates As Potential Vaccine Adjuvants, J. R. Adams, M. Goswami, N. L.B. Pohl, Surya K. Mallapragada

Chemical and Biological Engineering Publications

We report the synthesis of a family of amphiphilic pentablock polymers with different cationic blocks and with controlled architectures as potential vaccine carriers for subunit vaccines. The temperature and pH-dependent micellization and gelation of these pentablock copolymers can provide a depot for sustained protein and gene delivery. The amphiphilic central triblock promotes cellular endocytosis, good gene delivery and has been used effectively as a vaccine adjuvant. The pentablock copolymer outer blocks condense DNA spontaneously as a result of electrostatic interactions for sustained combinational therapy. This family of polymers with different cationic groups was evaluated based on DNA complexation-ability and cytotoxicity ...


Direct Pore‐Level Observation Of Permeability Increase In Two‐Phase Flow By Shaking, Igor A. Beresnev, William Gaul, R. Dennis Vigil Oct 2011

Direct Pore‐Level Observation Of Permeability Increase In Two‐Phase Flow By Shaking, Igor A. Beresnev, William Gaul, R. Dennis Vigil

Chemical and Biological Engineering Publications

Increases in permeability of natural reservoirs and aquifers by passing seismic waves have been well documented. If the physical causes of this phenomenon can be understood, technological applications would be possible for controlling the flow in hydrologic systems or enhancing production from oil reservoirs. The explanation of the dynamically increased mobility of underground fluids must lie at the pore level. The natural fluids can be viewed as two-phase systems, composed of water as the wetting phase and of dispersed non-wetting globules of gas or organic fluids, flowing through tortuous constricted channels. Capillary forces prevent free motion of the suspended non-wetting ...


Thickness Of Residual Wetting Film In Liquid-Liquid Displacement, Igor A. Beresnev, William Gaul, R. Dennis Vigil Aug 2011

Thickness Of Residual Wetting Film In Liquid-Liquid Displacement, Igor A. Beresnev, William Gaul, R. Dennis Vigil

Chemical and Biological Engineering Publications

Core-annular flow is common in nature, representing, for example, how streams of oil, surrounded by water, move in petroleum reservoirs. Oil, typically a nonwetting fluid, tends to occupy the middle (core) part of a channel, while water forms a surrounding wall-wetting film. What is the thickness of the wetting film? A classic theory has been in existence for nearly 50 years offering a solution, although in a controversial manner, for moving gas bubbles. On the other hand, an acceptable, experimentally verified theory for a body of one liquid flowing in another has not been available. Here we develop a hydrodynamic ...


Forced Instability Of Core-Annular Flow In Capillary Constrictions, Igor A. Beresnev, William Gaul, R. Dennis Vigil Jul 2011

Forced Instability Of Core-Annular Flow In Capillary Constrictions, Igor A. Beresnev, William Gaul, R. Dennis Vigil

Chemical and Biological Engineering Publications

Instability of fluid cylinders and jets, a highly nonlinear hydrodynamic phenomenon, has fascinated researchers for nearly 150 years. A subset of the phenomenon is the core-annular flow, in which a non-wetting core fluid and a surrounding wall-wetting annulus flow through a solid channel. The model, for example, represents the flow of oil in petroleum reservoirs. The flow may be forced to break up when passing through a channel’s constriction. Although it has long been observed that the breakup occurs near the neck of the constriction, the exact conditions for the occurrence of the forced breakup and its dynamic theory ...