Biomedical Engineering and Bioengineering Commons^™

Otx2 Represses Sister Cell Fate Choices In The Developing Retina To Promote Photoreceptor Specification, Miruna Georgiana Ghinia Tegla, Diego F. Buenaventura, Diana Y. Kim, Cassandra Thakurdin, Kevin C. Gonzalez, Mark M. Emerson

Publications and Research

During vertebrate retinal development, subsets of progenitor cells generate progeny in a non-stochastic manner, suggesting that these decisions are tightly regulated. However, the gene-regulatory network components that are functionally important in these progenitor cells are largely unknown. Here we identify a functional role for the OTX2 transcription factor in this process. CRISPR/Cas9 gene editing was used to produce somatic mutations of OTX2 in the chick retina and identified similar phenotypes to those observed in human patients. Single cell RNA sequencing was used to determine the functional consequences OTX2 gene editing on the population of cells derived from OTX2-expressing retinal progenitor …

Transcranial Electrical Stimulation Motor Threshold Can Estimate Individualized Tdcs Dosage From Reverse-Calculation Electric-Field Modeling, Kevin A. Caulfield, Bashar W. Badran, William H. Devries, Philipp M. Summers, Emma Kofmehl, Xingbao Li, Jeffrey J. Borckardt, Marom Bikson, Mark S. George

Publications and Research

Background

Unique amongst brain stimulation tools, transcranial direct current stimulation (tDCS) currently lacks an easy or widely implemented method for individualizing dosage.

Objective

We developed a method of reverse-calculating electric-field (E-field) models based on Magnetic Resonance Imaging (MRI) scans that can estimate individualized tDCS dose. We also evaluated an MRI-free method of individualizing tDCS dose by measuring transcranial magnetic stimulation (TMS) motor threshold (MT) and single pulse, suprathreshold transcranial electrical stimulation (TES) MT and regressing it against E-field modeling. Key assumptions of reverse-calculation E-field modeling, including the size of region of interest (ROI) analysis and the linearity of multiple E-field …

A Micro-Optic Stalk (Muos) System To Model The Collective Migration Of Retinal Neuroblasts, Stephanie Zhang, Miles Markey, Caroline D. Pena, Tadmiri Venkatesh, Maribel Vasquez

Publications and Research

Contemporary regenerative therapies have introduced stem-like cells to replace damaged neurons in the visual system by recapitulating critical processes of eye development. The collective migration of neural stem cells is fundamental to retinogenesis and has been exceptionally well-studied using the fruit fly model of Drosophila Melanogaster. However, the migratory behavior of its retinal neuroblasts (RNBs) has been surprisingly understudied, despite being critical to retinal development in this invertebrate model. The current project developed a new microfluidic system to examine the collective migration of RNBs extracted from the developing visual system of Drosophila as a model for the collective motile processes …

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 …

Transcutaneous Auricular Vagus Nerve Stimulation-Paired Rehabilitation For Oromotor Feeding Problems In Newborns: An Open-Label Pilot Study, Bashar W. Badran, Dorothea D. Jenkins, Daniel Cook, Sean Thompson, Morgan Darcy, William H. Devries, Georgia Mappin, Philipp Summers, Marom Bikson, Mark S. George

Publications and Research

Neonates born premature or who suffer brain injury at birth often have oral feeding dysfunction and do not meet oral intake requirements needed for discharge. Low oral intake volumes result in extended stays in the hospital (>2 months) and can lead to surgical implant and explant of a gastrostomy tube (G-tube). Prior work suggests pairing vagus nerve stimulation (VNS) with motor activity accelerates functional improvements after stroke, and transcutaneous auricular VNS (taVNS) has emerged as promising noninvasive form of VNS. Pairing taVNS with bottle-feeding rehabilitation may improve oromotor coordination and lead to improved oral intake volumes, ultimately avoiding the …

Theoretical Analysis Of The Leakage Through The Cement Line Of A Single Osteon, Gaffar Gailani, Stephen Cowin

Publications and Research

This work focuses on the Lacunar–Canalicular Porosity (PLC) of cortical bone which includes the osteons. Osteons are semicylindrical porous structures saturated with fluid within the bone and are approximately 250" role="presentation">μ" role="presentation">μm in diameter. The outer boundary of the osteon is called the cement line. Some studies suggested that the cement line is less highly mineralized and produced evidence that it has less calcium and phosphorus and more sulfur than the neighboring bone lamellae. Most authors assume that the cement line is impermeable, while others assume that some canaliculi are crossing the cement line which will make it …

In Vitro Evaluation Of The Influence Of Substrate Mechanics On Matrix-Assisted Human Chondrocyte Transplantation, Yueh-Hsun Kevin Yang, Courtney R. Ogando, Gilda A. Barabino

Publications and Research

Matrix-assisted chondrocyte transplantation (MACT) is of great interest for the treatment of patients with cartilage lesions. However, the roles of the matrix properties in modulating cartilage tissue integration during MACT recovery have not been fully understood. The objective of this study was to uncover the effects of substrate mechanics on the integration of implanted chondrocyte-laden hydrogels with native cartilage tissues. To this end, agarose hydrogels with Young’s moduli ranging from 0.49 kPa (0.5%, w/v) to 23.08 kPa (10%) were prepared and incorporated into an in vitro human cartilage explant model. The hydrogel-cartilage composites were cultivated for up to 12 weeks …

Enhanced Tes And Tdcs Computational Models By Meninges Emulation, Jimmy Jiang, Dennis Q. Truong, Zeinab Esmaeilpour, Yu Huang, Bashar W. Badran, Marom Bikson

Publications and Research

Objective. Understanding how current reaches the brain during transcranial electrical stimulation (tES) underpins efforts to rationalize outcomes and optimize interventions. To this end, computational models of current flow relate applied dose to brain electric field. Conventional tES modeling considers distinct tissues like scalp, skull, cerebrospinal fluid (CSF), gray matter and white matter. The properties of highly conductive CSF are especially important. However, modeling the space between skull and brain as entirely CSF is not an accurate representation of anatomy. The space conventionally modeled as CSF is approximately half meninges (dura, arachnoid, and pia) with lower conductivity. However, the resolution …

Mems Biosensor For Water-Immersed Application, Kun-Lin Lee

Dissertations and Theses

Although many air-based sensing mechanisms exist, not all of them can be applied in the water-based environment. In order to obtain a cell-based biosensor, the sensing method needs to be reliable and repeatable in a liquid environment. Therefore, this study is focused on transforming existing air-based sensors to water-immersed applications. This study includes two types of sensors.

First, commercial quartz resonators are used to investigate live-cell activity in water-based toxic solutions. I perform toxicity tests using quartz crystal microbalance (QCM). The QCM used in the study has a resonant frequency of 10 MHz and consists of an AT-cut quartz crystal …

Influence Of Transdermal Current Flow In Tdcs-Induced Cutaneous Adverse Events, Niranjan Khadka

Dissertations and Theses

Significant contributors to the broad application of transcranial direct current stimulation (tDCS) are portability, ease-of-use, and tolerability; with adverse events limited to transient and mild cutaneous sensations (e.g. perception of burning, itching, and tingling) and erythema. However, the fundamental questions remain about the mechanism of transdermal current flow during transcranial electrical stimulation, including tDCS. Example of previously unexplained questions in tDCS include: 1) the relationship between tDCS-induced skin reddening (erythema) profile and local current density profile predicted by the model; 2) the source of burning sensation during tDCS and whether it is related to an actual skin heating; 3) the …

Diffuse Damage Repair Mechanism In Bone, Leila Mehraban Alvandi

Dissertations and Theses

Bone microdamage is a result of fatigue, creep or ‘wear and tear’ caused by physiological activities and largely contributes to bone fragility. Bone, unlike engineered materials, has the ability to repair the microscopic cracking or microdamage through targeted, osteoclast-mediated bone remodeling. This capability is crucial for preservation of its structural integrity and quality; failure of the skeleton to effectively repair microdamage leads to accumulation of damage, which is one of the main contributors to bone fragility. Linear microcracks (50-100 µm) and diffuse damage (Dif.Dx) (sub-micron) are the two types of microdamage. Recent studies show that Dif.Dx repairs without bone remodeling, …

Characterization Of Bone Pathology In Sickle Cell Disease And Therapeutic Strategies, Mykel D. Green

Dissertations and Theses

Sickle cell disease (SCD) is a genetic hemoglobinopathy that has grown into a global health concern. While the advances in medical treatment and management of SCD during childhood have drastically improved the overall survival of children, the transition from pediatric to adult services is significantly inadequate in comparison. Life expectancies of patients with SCD in first world countries such as the United States are shortened to averages of 42 and 48 years for men and women, respectively. Despite the increasing number of people living with SCD, remarkably, few detailed studies have described the clinical course and complications of the disease …

Attention Strongly Modulates Reliability Of Neural Response To Naturalistic Narrative Stimuli, Jason Ki

Dissertations and Theses

Attentional engagement is a major determinant of how effectively we gather information through our senses. Alongside the sheer growth in the amount and variety of information content we are presented with through modern media, there is increased variability in the degree to which we ‘absorb’ that information. Traditional research on attention has illuminated the basic principles of sensory selection to isolated features or locations, but it provides little insight into the neural underpinnings of our attentional engagement with modern naturalistic content. Here, we show in human subjects that the reliability of an individual's neural responses with respect to a larger …

Effects Of Weak Electric Fields On Long-Term Synaptic Plasticity, Gregory Kronberg

Dissertations and Theses

Transcranial direct current stimulation (tDCS) is a technique where a weak direct electrical current is applied to the scalp with the goal of stimulating the brain. There is tremendous interest in the use of tDCS for treating brain disorders and improving brain function. However, the effects of tDCS have been highly variable across studies, leading to a debate over its efficacy. A major challenge is therefore to design tDCS protocols that yield predictable effects, which will require a better understanding of its basic mechanisms of action. One commonly discussed mechanism is that tDCS may alter synaptic plasticity, but the biophysics …

Invertebrate Retinal Progenitors As Regenerative Models In A Microfluidic System, Caroline D. Pena, Stephanie Zhang, Robert Majeska, Tadmiri Venkatesh, Maribel Vazquez

Publications and Research

Regenerative retinal therapies have introduced progenitor cells to replace dysfunctional or injured neurons and regain visual function. While contemporary cell replacement therapies have delivered retinal progenitor cells (RPCs) within customized biomaterials to promote viability and enable transplantation, outcomes have been severely limited by the misdirected and/or insuffcient migration of transplanted cells. RPCs must achieve appropriate spatial and functional positioning in host retina, collectively, to restore vision, whereas movement of clustered cells differs substantially from the single cell migration studied in classical chemotaxis models. Defining how RPCs interact with each other, neighboring cell types and surrounding extracellular matrixes are critical to …

Medical Dental Device: Biogeneric Implant Prototype, Ibeth Erazo, Aneeza Hussain, Renata Budny, Gaffar Gailani

Publications and Research

Teeth are lost due to tooth decay, injury, disease, or other causes. Today, dental implants extend the range of care to a variety of patients undergoing necessary prosthodontic rehabilitation. If the benefits of such treatments are to be maximized, then implants must be selected on logical basis and placed within the context of the full range of treatment modalities. However, modern dental implant systems are based on multiple components often leading to micro-movements which cause stress on the bone or bacterial infections, both of which compromise the success of osseointegration and consequently jeopardize the whole implant adaptation. Thus, a new …

Advanced Design And Fabrication Of Prosthetic And Medical Devices, Gaffar Gailani, Andy S. Zhang, Yu Wang, Sidi Berri

Publications and Research

The department of Mechanical Engineering and Industrial Design Technology (MEIDT) at City Tech is seeking to strengthening the skills of its students in manufacturing and design to respond to the urgent needs of the manufacturing industry in general and the prosthetic and medical devices (P&MD) industry in particular to high-skilled engineers and technicians and to provide a national model for advanced technology education. Medical Devices will include: (a) Surgical and Medical Instruments; (b) Surgical Appliances and Supplies; and (c) Dental Equipment and Supplies. The educational merit of the project is that it motivates students to do engineering rather than studying …

Composite Biomaterial Repair Strategy To Restore Biomechanical Function And Reduce Herniation Risk In An Ex Vivo Large Animal Model Of Intervertebral Disc Herniation With Varying Injury Severity, Warren W. Hom, Melanie Tschopp, Huizi A. Lin, Philip Nasser, Damien M. Laudier, Andrew C. Hecht, Steven B. Nicoll, James C. Iatridis

Publications and Research

Back pain commonly arises from intervertebral disc (IVD) damage including annulus fibrosus (AF) defects and nucleus pulposus (NP) loss. Poor IVD healing motivates developing tissue engineering repair strategies. This study evaluated a composite injectable IVD biomaterial repair strategy using carboxymethylcellulose-methylcellulose (CMC-MC) and genipincrosslinked fibrin (FibGen) that mimic NP and AF properties, respectively. Bovine ex vivo caudal IVDs were evaluated in cyclic compression-tension, torsion, and compression-to-failure tests to determine IVD biomechanical properties, height loss, and herniation risk following experimentally-induced severe herniation injury and discectomy (4 mm biopsy defect with 20% NP removed). FibGen with and without CMC-MC had failure strength similar …

The Effect Of Heterobifunctional Crosslinkers On Hema Hydrogel Modulus And Toughness, Elizabeth M. Boazak, Vaughn K. Greene Jr., Debra T. Auguste

Publications and Research

The use of hydrogels in load bearing applications is often limited by insufficient toughness. 2-Hydroxyethyl methacrylate (HEMA) based hydrogels are appealing for translational work, as they are affordable and the use of HEMA is FDA approved. Furthermore, HEMA is photopolymerizable, providing spatiotemporal control over mechanical properties. We evaluated the ability of vinyl methacrylate (VM), allyl methacrylate (AM), and 3-(Acryloyloxy)-2-hydroxypropyl methacrylate (AHPM) to tune hydrogel toughness and Young’s modulus. The crosslinkers were selected due to their heterobifunctionality (vinyl and methacrylate) and similar size and structure to EGDMA, which was shown previously to increase toughness as compared to longer crosslinkers. Vinyl methacrylate …

The Modeling, Design, Fabrication, And Application Of Biosensor Based On Electric Cell-Substrate Impedance Sensing (Ecis) Technique In Environmental Monitoring, Xudong Zhang, William Wang, Sunghoon Jang

Publications and Research

In this research, the modeling, design, fabrication, and application of ECIS sensors in environmental monitoringare studied. The ECIS sensors are able to qualify the water toxicity through measuring the cell impedance. A novel mathematical model is proposed to analyze the distribution of electric potential and current of ECIS. This mathematical model is validated by experimental data and can be used to optimize the dimension of ECIS electrodes in order to satisfy environmental monitors. The detection sensitivity of ECIS sensors is analyzed by the mathematical model and experimental data. The simulated and experimental results show that ECIS sensors with smaller radius …

Bioelectrical Circuits: Lecture 7, Jacek P. Dmochowski, Luis Cardoso

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No abstract provided.

Bioelectrical Circuits: Lecture 8, Jacek P. Dmochowski, Luis Cardoso

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Bioelectrical Circuits: Lecture 9, Jacek P. Dmochowski, Luis Cardoso

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Bioelectrical Circuits: Lecture 2, Jacek P. Dmochowski, Luis Cardoso

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Bioelectrical Circuits: Lecture 5, Jacek P. Dmochowski, Luis Cardoso

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Bioelectrical Circuits: Lecture 10, Jacek P. Dmochowski, Luis Cardoso

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Bioelectrical Circuits: Lecture 6, Jacek P. Dmochowski, Luis Cardoso

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Bioelectrical Circuits: Lecture 4, Jacek P. Dmochowski, Luis Cardoso

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Bme 20500 Bioelectrical Circuits, Jacek P. Dmochowski, Luis Cardoso

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Bioelectrical Circuits: Lecture 1, Jacek P. Dmochowski, Luis Cardoso

Open Educational Resources

No abstract provided.