Biomedical Engineering and Bioengineering Commons^™

Carboxymethylcellulose Hydrogels Support Central Nervous System-Derived Tumor-Cell Chemotactic Migration: Comparison With Conventional Extracellular Matrix Macromolecules, Tanya Singh, Chandrasekhar Kothapalli, Devika Varma, Steven B. Nicoll, Maribel Vazquez

Publications and Research

The local microenvironment plays an important role in maintaining the dynamics of the extracellular matrix and the cell-extracellular matrix relationship. The extracellular matrix is a complex network of macromolecules with distinct mechanical and biochemical characteristics. Disruptions in extracellular matrix homeostasis are associated with the onset of cancer. The extracellular matrix becomes highly disorganized, and the cell-matrix relationship changes, resulting in altered cell-signaling processes and metastasis. Medulloblastoma is one of the most common malignant pediatric brain tumors in the United States. In order to gain a better understanding of the interplay between cell-extracellular matrix interactions and cell-migratory responses in tumors, eight …

Utilizing Fast Spin Echo Mri To Reduce Image Artifacts And Improve Implant/Tissue Interface Detection In Refractory Parkinson’S Patients With Deep Brain Stimulators, Subhendra N. Sarkar, Pooja R. Sarkar, Efstathios Papavassiliou, Rafael Rojas

Publications and Research

Introduction. In medically refractory Parkinson’s disease (PD) deep-brain stimulation (DBS) is an effective therapeutic tool. Postimplantation MRI is important in assessing tissue damage and DBS lead placement accuracy. We wanted to identify which MRI sequence can detectDBS leads with smallest artifactual signal void, allowing better tissue/electrode edge conspicuity.

Methods. Using an IRB approved protocol 8 advanced PDpatientswere imagedwithinMRconditional safety guidelines at lowRF power (SAR ≤ 0.1 W/kg) in coronal plane at 1.5T by various sequences.The image slices were subjectively evaluated for diagnostic quality and the lead contact diameters were compared to identify a sequence least affected by metallic leads.

Results …

Microfluidic Generated Egf-Gradients Induce Chemokinesis Of Transplantable Retinal Progenitor Cells Via The Jak/Stat And Pi3kinase Signaling Pathways., Uchenna J. Unachukwu, Moira Sauane, Maribel Vazquez, Stephen Redenti

Publications and Research

A growing number of studies are evaluating retinal progenitor cell (RPC) transplantation as an approach to repair retinal degeneration and restore visual function. To advance cell-replacement strategies for a practical retinal therapy, it is important to define the molecular and biochemical mechanisms guiding RPC motility. We have analyzed RPC expression of the epidermal growth factor receptor (EGFR) and evaluated whether exposure to epidermal growth factor (EGF) can coordinate motogenic activity in vitro. Using Boyden chamber analysis as an initial high-throughput screen, we determined that RPC motility was optimally stimulated by EGF concentrations in the range of 20-400 ng/ml, with decreased …

Biomarkers For Brain Disorders Electrochemically Detected By Broderick Probe Microelectrodes/Biosensors, Waqas Saleem, Patricia A. Broderick

Publications and Research

Here, we present results from two independent studies carried out using Neuromolecular Imaging (NMI) with miniature BRODERICK PROBE® biosensors. In the first study, we imaged neurotransmitters and neurochemicals in human epilepsy patients intraoperatively during early and late neurodegeneration. In the second study, we imaged neurotransmitters and neurochemicals in an experimental murine model using animals with and without neurodegeneration caused by Parkinson’s disease (PD). We compared our results derived from animals with lesioned group (PD) with non-lesioned group (non-PD), using the same in vivo NMI paradigm. NMI biotechnology enabled neurotransmitters, neuropeptides and neurochemical imaging of dopamine (DA), serotonin (5-HT), homovanillic acid …

Role Of Epidermal Growth Factor-Triggered Pi3k/Akt Signaling In The Migration Of Medulloblastoma-Derived Cells, Veronica Dudu, Richard A. Able, Jr., Veronica Rotari, Qingjun Kong, Maribel Vazquez

Publications and Research

Medulloblastoma (MB) is the most common brain cancer diagnosed among children. The cellular pathways that regulate MB invasion in response to environmental cues remain incompletely understood. Herein, we examine the migratory response of human MB-derived Daoy cells to different concentration profiles of Epidermal Growth Factor (EGF) using a microfluidic system. Our findings provide the first quantitative evidence that EGF concentration gradients modulate the chemotaxis of MB-derived cells in a dose-dependent manner via the EGF receptor (EGF-R). Data illustrates that higher concentration gradients caused increased number of cells to migrate. In addition, our results show that EGF-induced receptor phosphorylation triggered the …

Computational Model Of Neuron-Astrocyte Interputational Model Of Neuron-Astrocyte Interactions During Focal Seizure Generationactions During Focal Seizure Generation, Davide Reato, Mario Cammarota, Lucas C. Parra, Giorgio Carmignoto

Publications and Research

Empirical research in the last decade revealed that astrocytes can respond to neurotransmitters with Ca2+ elevations and generate feedback signals to neurons which modulate synaptic transmission and neuronal excitability. This discovery changed our basic understanding of brain function and provided new perspectives for how astrocytes can participate not only to information processing, but also to the genesis of brain disorders, such as epilepsy. Epilepsy is a neurological disorder characterized by recurrent seizures that can arise focally at restricted areas and propagate throughout the brain. Studies in brain slice models suggest that astrocytes contribute to epileptiform activity by increasing neuronal excitability …

Sendai Virus-Based Liposomes Enable Targeted Cytosolic Delivery Of Nanoparticles In Brain Tumor-Derived Cells, Veronica Dudu, Veronica Rotari, Maribel Vazquez

Publications and Research

BACKGROUND: Nanotechnology-based bioassays that detect the presence and/or absence of a combination of cell markers are increasingly used to identify stem or progenitor cells, assess cell heterogeneity, and evaluate tumor malignancy and/or chemoresistance. Delivery methods that enable nanoparticles to rapidly detect emerging, intracellular markers within cell clusters of biopsies will greatly aid in tumor characterization, analysis of functional state and development of treatment regimens.

RESULTS: Experiments utilized the Sendai virus to achieve in vitro, cytosolic delivery of Quantum dots in cells cultured from Human brain tumors. Using fluorescence microscopy and Transmission Electron Microscopy, in vitro experiments illustrated that these virus-based …

Migration And Invasion Of Brain Tumors, Richard A. Able, Jr., Veronica Dudu, Maribel Vazquez

Publications and Research

Recent advances in molecular biology have led to new insights in the development, growth and infiltrative behaviors of primary brain tumors (Demuth and Berens, 2004; Huse and Holland, 2010; Johnson et al., 2009; Kanu et al., 2009). These tumors are derived from various brain cell lineages and have been historically classified on the basis of morphological and, more recently, immunohistochemical features with less emphasis on their underlying molecular pathogenesis (Huse and Holland, 2010). The detailed molecular characterization of brain tumors has laid the groundwork for augmentation of standard treatment with patient-specific designed targeted therapies (Johnson et al., 2009; Kanu et …

Bitten By The Science Bug (Nycsef 2011), Maribel Vazquez

Publications and Research

The invited keynote address to the participants of the final round of the 2011 New York City Science and Engineering Fair (NYCSeF) at the American Museum of Natural History (AMNH).

A Microfluidic Device To Establish Concentration Gradients Using Reagent Density Differences, Qingjun Kong, Richard A. Able, Jr., Veronica Dudu, Maribel Vazquez

Publications and Research

Microfabrication has become widely utilized to generate controlled microenvironments that establish chemical concentration gradients for a variety of engineering and life science applications. To establish microfluidic flow, the majority of existing devices rely upon additional facilities, equipment, and excessive reagent supplies, which together limit device portability as well as constrain device usage to individuals trained in technological disciplines. The current work presents our laboratory-developed bridged microLane system, which is a stand-alone device that runs via conventional pipette loading and can operate for several days without need of external machinery or additional reagent volumes. The bridged microLane is a two-layer polydimethylsiloxane …

Metallic Nanoparticle On Micro Ring Resonator For Bio Optical Detection And Sensing, Ali Haddadpour, Yasha Yi

Publications and Research

We have numerically investigated the unique effects of metallic nanoparticle on the ring resonator, especially multiple Au nanoparticles on the micro ring resonator with the 4-port configuration on chip. For the Au nanoparticle, because it has smaller real refractive index than air and large absorption refractive index, we found that there is a blue shift for the ring resonance wavelength, instead of red shift normally observed for dielectric nanoparticles. The drop port intensity is strongly dependent on both number and size of nanoparticles, while relatively independent on position of nanoparticles. The correlation between the penetration depth of Au and the …

Development Of A Mechanical System For Osteon Isolation, S. Ranglin, D. Das, A. Mingo, O. Ukinamemen, Gaffar Gailani, S. Cowin, L. Cardoso

Publications and Research

Osteons are small semi cylindrical hard tissues that exist in long bones of humans and some animals. Their diameter is in the range of 250 – 300 micrometers approximately. They contain the osteocytes which plays a role in bone mechanotransduction. The boundary that surrounds the osteon from outside is called the cement line. In a summer research project supported by CUNY-LSAMP a group of four students and three professors worked full summer to develop a system that can isolate the osteons thus a mechanical testing could be performed (stress relaxation test) to determine their poroelastic properties. Two sets of osteons …

Low Concentration Microenvironments Enhance The Migration Of Neonatal Cells Of Glial Lineage, Richard A. Able, Jr., Celestin Ngnabeuye, Cade Beck, Eric C. Holland, Maribel Vazquez

Publications and Research

Glial tumors have demonstrated abilities to sustain growth via recruitment of glial progenitor cells (GPCs), which is believed to be driven by chemotactic cues. Previous studies have illustrated that mouse GPCs of different genetic backgrounds are able to replicate the dispersion pattern seen in the human disease. How GPCs with genetic backgrounds transformed by tumor paracrine signaling respond to extracellular cues via migration is largely unexplored, and remains a limiting factor in utilizing GPCs as therapeutic targets. In this study, we utilized a microfluidic device to examine the chemotaxis of three genetically-altered mouse GPC populations towards tumor conditioned media, as …