Biomedical Engineering and Bioengineering Commons^™

Recent Approaches In Designing Bioadhesive Materials Inspired By Mussel Adhesive Protein, Pegah Kord Forooshani, Bruce P. Lee

Bruce Lee

Marine mussels secret protein-based adhesives, which enable them to anchor to various surfaces in a saline, intertidal zone. Mussel foot proteins (Mfps) contain a large abundance of a unique, catecholic amino acid, Dopa, in their protein sequences. Catechol offers robust and durable adhe-sion to various substrate surfaces and contributes to the curing of the adhesive plaques. In this article, we review the unique features and the key functionalities of Mfps, catechol chemistry, and strategies for preparing catechol-functionalized poly- mers. Specifically, we reviewed recent findings on the contributions of various features of Mfps on interfacial binding, which include coacervate formation, surface …

Person Identification From Streaming Surveillance Video Using Mid-Level Features From Joint Action-Pose Distribution, Binu M. Nair, Vijayan K. Asari

Vijayan K. Asari

We propose a real time person identification algorithm for surveillance based scenarios from low-resolution streaming video, based on mid-level features extracted from the joint distribution of various types of human actions and human poses. The proposed algorithm uses the combination of an auto-encoder based action association framework which produces per-frame probability estimates of the action being performed, and a pose recognition framework which gives per-frame body part locations. The main focus in this manuscript is to effectively combine these per-frame action probability estimates and pose trajectories from a short temporal window to obtain mid-level features. We demonstrate that these mid-level …

Video-To-Video Pose And Expression Invariant Face Recognition Using Volumetric Directional Pattern, Vijayan K. Asari, Almabrok Essa

Vijayan K. Asari

Face recognition in video has attracted attention as a cryptic method of human identification in surveillance systems. In this paper, we propose an end-to-end video face recognition system, addressing a difficult problem of identifying human faces in video due to the presence of large variations in facial pose and expression, and poor video resolution. The proposed descriptor, named Volumetric Directional Pattern (VDP), is an oriented and multi-scale volumetric descriptor that is able to extract and fuse the information of multi frames, temporal (dynamic) information, and multiple poses and expressions of faces in input video to produce feature vectors, which are …

Gaussian Nonlinear Line Attractor For Learning Multidimensional Data, Theus H. Aspiras, Vijayan K. Asari, Wesam Sakla

Vijayan K. Asari

The human brain’s ability to extract information from multidimensional data modeled by the Nonlinear Line Attractor (NLA), where nodes are connected by polynomial weight sets. Neuron connections in this architecture assumes complete connectivity with all other neurons, thus creating a huge web of connections. We envision that each neuron should be connected to a group of surrounding neurons with weighted connection strengths that reduces with proximity to the neuron. To develop the weighted NLA architecture, we use a Gaussian weighting strategy to model the proximity, which will also reduce the computation times significantly. Once all data has been trained in …

Estimating Effective Connectivity From Fmri Data Using Factor-Based Subspace Autoregressive Models, Chee-Ming Ting Phd, Abd-Krim Seghouane Phd, Sh-Hussain Salleh Phd, Alias M. Noor Phd

Chee-Ming Ting

Estimation Of High-Dimensional Brain Connectivity From Fmri Data Using Factor Modeling, Chee-Ming Ting Phd, Abd-Krim Seghouane, Sh-Hussain Salleh, Alias M. Noor

Chee-Ming Ting

We consider identifying effective connectivity of brain networks from fMRI time series. The standard vector autoregressive (VAR) models fail to give reliable network estimates, typically involving very large number of nodes. This paper adopts a dimensionality reduction approach based on factor modeling, to enable effective and efficient high-dimensional VAR analysis of large network connectivity. We derive a subspace VAR (SVAR) model from the factor model (FM) in which the observations are driven by a lower dimensional subspace of common latent factors, following an autoregressive dynamics. We consider the principal components (PC) method which can produce consistent estimators for the FM, …

Electrochemically Modulated Permeability Of Poly(Aniline) And Composite Poly(Aniline)−Poly(Styrenesulfonate) Membranes, D. L. Pile, Y. Zhang, Andrew C. Hillier

Andrew C. Hillier

The influence of oxidation state on the permeability of several probe molecules through conducting polymer membranes comprising composites of poly(aniline) and poly(styrenesulfonate) was examined in aqueous solution. Pure poly(aniline) membranes displayed a characteristic increase in permeability between reduced and half-oxidized states for neutrally charged phenol and negatively charged 4-hydroxybenzenesulfonate. In contrast, positively charged pyridine experienced decreased permeability through the membrane when poly(aniline) was switched from the reduced to the half-oxidized state. This behavior can be explained by a combination of oxidation-induced film swelling and the anion-exchange character of the positively charged membrane. The membrane composition was modified to include a …

Scanning Electrochemical Mapping Of Spatially Localized Electrochemical Reactions Induced By Surface Potential Gradients, Shrisudersan Jayaraman, Erin L. May, Andrew C. Hillier

Andrew C. Hillier

The influence of a surface potential gradient on the location and extent of electrochemical reactions was examined using a scanning electrochemical microscope. A linear potential gradient was imposed on the surface of a platinum-coated indium tin oxide electrode by applying two different potential values at the edges of the electrode. The applied potentials were used to control the location and extent of several electrochemical reactions, including the oxidation of Ru(NH3)62+, the oxidation of H2, and the oxidation of H2 in the presence of adsorbed CO. Scanning electrochemical mapping of these reactions was achieved by probing the feedback current associated with …

High Rate Detection Of Volatile Products Using Differential Electrochemical Mass Spectrometry: Combining An Electrode-Coated Membrane With Hydrodynamic Flow In A Wall-Tube Configuration, Subramanian Venkatachalam, Robert J. Angelici, L. Keith Woo, Andrew C. Hillier

Andrew C. Hillier

We present an experimental system that combines differential electrochemical mass spectrometry with hydrodynamic flow consisting of an impinging jet in a wall-tube configuration. This assembly allows simultaneous detection of electrochemical signals along with monitoring of dissolved gas species using differential electrochemical mass spectrometry under well-defined hydrodynamic conditions and over a wide range of mass transfer rates. The working electrode is deposited directly onto a thin, hydrophobic membrane, which also serves as the inlet to the mass spectrometer. This inlet provides extremely rapid mass detection as well as a high flux of products from the electrode surface into the mass spectrometer. …

Fabrication Of Low-Cost Paper-Based Microfluidic Devices By Embossing Or Cut-And-Stack Methods, Martin M. Thuo, Ramses V. Martinez, Wen-Jie Lan, Xinyu Liu, Jabulani Barber, Manza B. Atkinson, Dineth Bandarage, Jean-Francis Bloch, George M. Whitesides

Martin M. Thuo

This article describes the use of embossing and “cut-and-stack” methods of assembly, to generate microfluidic devices from omniphobic paper and demonstrates that fluid flowing through these devices behaves similarly to fluid in an open-channel microfluidic device. The porosity of the paper to gases allows processes not possible in devices made using PDMS or other nonporous materials. Droplet generators and phase separators, for example, could be made by embossing “T”-shaped channels on paper. Vertical stacking of embossed or cut layers of omniphobic paper generated three-dimensional systems of microchannels. The gas permeability of the paper allowed fluid in the microchannel to contact …

Construction Of A Tethered Poly(Ethylene Glycol) Surface Gradient For Studies Of Cell Adhesion Kinetics, K. Mougin, A. S. Ham, M. B. Lawrence, E. J. Fernandez, Andrew C. Hillier

Andrew C. Hillier

Surface gradients can be used to perform a wide range of functions and represent a novel experimental platform for combinatorial discovery and analysis. In this work, a gradient in the coverage of a surface-immobilized poly(ethylene glycol) (PEG) layer is constructed to interrogate cell adhesion on a solid surface. Variation of surface coverage is achieved by controlled transport of a reactive PEG precursor from a point source through a hydrated gel. Immobilization of PEG is achieved by covalent attachment of the PEG molecule via direct coupling chemistry to a cystamine self-assembled monolayer on gold. This represents a simple method for creating …

Construction Of Cell-Resistant Surfaces By Immobilization Of Poly(Ethylene Glycol) On Gold, K. Mougin, M. B. Lawrence, E. J. Fernandez, Andrew C. Hillier

Andrew C. Hillier

Considerable effort has been expended in efforts to create surfaces that resist the adsorption of proteins and cells for biomedical applications. The majority of such work has focused on surfaces constructed from bulk polymers or thin polymer films. However, the fabrication of surfaces via self-assembled monolayers (SAMs) has attracted considerable interest because of the robustness, versatility, and wide-ranging applicability of these materials. SAMs are particularly appealing for biological systems where well-defined surface chemistries can be created to facilitate coupling, biorecognition, or cell adhesion along with a host of other applications in biochemistry and biotechnology.

Xena: An Automated 'Open-Source' 129xe Hyperpolarizer For Clinical Use, Panayiotis Nikolaou, Aaron M. Coffey, Laura L. Walkup, Brogan M. Gust, Nicholas Whiting, Hayley Newton, Iga Muradyan, Mikayel Dabaghyan, Kaili Ranta, Gregory D. Moroz, Matthew S. Rosen, Samuel Patz, Michael J. Barlow, Eduard Y. Chekmenev, Boyd M. Goodson

Nicholas Whiting

Computational Design Optimization For Microfluidic Magnetophoresis, Brian Dennis Plouffe, Laura H. Lewis, Shashi Krishna Murthy

Laura H. Lewis

Current macro- and microfluidic approaches for the isolation of mammalian cells are limited in both efficiency and purity. In order to design a robust platform for the enumeration of a target cell population, high collection efficiencies are required. Additionally, the ability to isolate pure populations with minimal biological perturbation and efficient off-chip recovery will enable subcellular analyses of these cells for applications in personalized medicine. Here, a rational design approach for a simple and efficient device that isolates target cell populations via magnetic tagging is presented. In this work, two magnetophoretic microfluidic device designs are described, with optimized dimensions and …

Inhibition Of Bacillus Cereus Growth By Bacteriocin Producing Bacillus Subtilis Isolated From Fermented Baobab Seeds (Maari) Is Substrate Dependent, Donatien Kaboré, Dennis S. Nielsen, Hagrétoui Sawadogo-Lingan, Bréhima Diawara, Mamoudou H. Dicko Prof., Mogens Jakobsen, Line Thorsen

Pr. Mamoudou H. DICKO, PhD

Microfabricated Nanotopological Surfaces For Study Of Adhesion-Dependent Cell Mechanosensitivity, Weiqiang Chen, Yubing Sun, Jianping Fu

Weiqiang Chen

Cells exhibit high sensitivity and diverse responses to the intrinsic nanotopography of the extracellular matrix through their nanoscale cellular sensing machinery. A simple microfabrication method for precise control and spatial patterning of the local nanoroughness on glass surfaces by using photolithography and reactive ion etching is reported. It is demonstrated that local nanoroughness as a biophysical cue could regulate a diverse array of NIH/3T3 fi broblast behaviors, including cell morphology, adhesion, proliferation, migration, and cytoskeleton contractility. The capability to control and further predict cellular responses to nanoroughness might suggest novel methods for developing biomaterials mimicking nanotopographic structures in vivo for …

Surface-Micromachined Microfiltration Membranes For Efficient Isolation And Functional Immunophenotyping Of Subpopulations Of Immune Cells, Weiqiang Chen, Nien-Tsu Huang, Boram Oh, Raymond H. W. Lam, Rong Fan, Timothy T. Cornell, Thomas P. Shanley, Katsuo Kurabayashi, Jianping Fu

Weiqiang Chen

An accurate measurement of the immune status in patients with immune system disorders is critical in evaluating the stage of diseases and tailoring drug treatments. The functional cellular immunity test is a promising method to establish the diagnosis of immune dysfunctions. The conventional functional cellular immunity test involves measurements of the capacity of peripheral blood mononuclear cells to produce pro-inflammatory cytokines when stimulated ex vivo. However, this “bulk” assay measures the overall reactivity of a population of lymphocytes and monocytes, making it difficult to pinpoint the phenotype or real identity of the reactive immune cells involved. In this research, we …

Local Fractional Variational Iteration Method For Fractal Heat Transfer In Silk Cocoon Hierarchy, Ji-Huan He

Ji-Huan He

A local fractional equation is established for fractal heat transfer in silk cocoon hierarchy, and the local fractional variational iteration method is adopted to solve the equation analytically. The result can well explain the intriguing phenomenon for pupa's survival at extremes of weather from negative 40 degrees to 50 degrees.

Correct Spectral Conversion Between Surface‐Enhanced Raman And Plasmon Resonance Scattering From Nanoparticle Dimers For Single‐Molecule Detection, Kyuwan Lee

Kyuwan Lee

Simultaneous measurement of surface-enhanced Raman scattering (SERS) and localized surface plasmon resonance (LSPR) in nanoparticle dimers presents outstanding opportunities in molecular identification and in the elucidation of physical properties, such as the size, distance, and deformation of target species. SERS–LSPR instrumentation exists and has been used under limited conditions, but the extraction of SERS and LSPR readouts from a single measurement is still a challenge. Herein, the extraction of LSPR spectra from SERS signals is reported and a tool for measuring the interparticle distance from Raman enhancement data by the standardization of the SERS signal is proposed. The SERS nanoruler …

Nanoroughened Surfaces For Efficient Capture Of Circulating Tumor Cells Without Using Capture Antibodies, Weiqiang Chen, Shinuo Weng, Feng Zhang, Steven Allen, Xiang Li, Liwei Bao, Raymond H. W. Lam, Jill A. Macoska, Sofia D. Merajver, Jianping Fu

Weiqiang Chen

Circulating tumor cells (CTCs) detached from both primary and metastatic lesions represent a potential alternative to invasive biopsies as a source of tumor tissue for the detection, characterization and monitoring of cancers. Here we report a simple yet effective strategy for capturing CTCs without using capture antibodies. Our method uniquely utilized the differential adhesion preference of cancer cells to nanorough surfaces when compared to normal blood cells and thus did not depend on their physical size or surface protein expression, a significant advantage as compared to other existing CTC capture techniques.

Comparison Of Phenolic Compounds And Antioxidant Capacities Of Traditional Sorghum Beers With Other Alcoholic Beverages, Fatouma Abdoul-Latif, Romaric G. Bayili, Louis C. Obame, Mamoudou H. Dicko Prof.

Pr. Mamoudou H. DICKO, PhD

Thirty samples of sorghum beers “dolo” were selected from traditionally fermented household manufacturers from Burkina Faso. Dolo samples were screened for their total phenolic content, proanthocyanidins and putative antioxidant capacities, and were compared with industrial beers and wines. Total phenols were measured using the Folin-Ciocalteu method. Proanthocyanidins content were determined by the method of HCl-butanol hydrolysis. Antioxidant activities were evaluated both with 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay and by the trolox equivalent antioxidant capacity (TEAC) using 2,2’-azinobis(3-ethyl-benzothiazoline-6-sulfonic acid radical) (ABTS•+). The average contents of total phenols and proanthocyanidins were 506 μg GAE/ml of dolo and 45 μg APE/ml of dolo, respectively. An …

Toxicity Assessment And Analgesic Activity Investigation Of Aqueous Acetone Extracts Of Sida Acuta Burn F. And Sida Cordifolia L. (Malvaceae), Medicinal Plants Of Burkina Faso, Kiessoum Konate, Adama Hilou, Raïssa Rr Aworet-Samseny, Alain Souza, Nicolas Barro, Mamoudou H. Dicko Prof., Jacques Datté, Bertrand M’Batchi

Pr. Mamoudou H. DICKO, PhD

Background Sida acuta Burn f. and Sida cordifolia L. (Malvaceae) are traditionally used in Burkina Faso to treat several ailments, mainly pains, including abdominal infections and associated diseases. Despite the extensive use of these plants in traditional health care, literature provides little information regarding their toxicity and the pharmacology. This work was therefore designed to investigate the toxicological effects of aqueous acetone extracts of Sida acuta Burn f. and Sida cordifolia L. Furthermore, their analgesic capacity was assessed, in order to assess the efficiency of the traditional use of these two medicinal plants from Burkina Faso. Method For acute toxicity …

Antibacterial Activity Against Beta- Lactamase Producing Methicillin And Ampicillin-Resistants Staphylococcus Aureus: Fractional Inhibitory Concentration Index (Fici) Determination, Kiessoun K Onate, Jacques François Mavoungou, Alexis Nicaise Lepengué, Raïssa Rr Aworet-Samseny, Adama Hilou, Mamoudou H. Dicko Prof., Bertrand M’Batchi

Pr. Mamoudou H. DICKO, PhD

The present study reports the antibacterial capacity of alkaloid compounds in combination with Methicillin and Ampicillin-resistants bacteria isolated from clinical samples. The resistance of different bacteria strains to the current antibacterial agents, their toxicity and the cost of the treatment have led to the development of natural products against the bacteria resistant infections when applied in combination with conventional antimicrobial drugs. The antibacterial assays in this study were performed by using inhibition zone diameters, MIC, MBC methods, the time-kill assay and the Fractional Inhibitory Concentration Index (FICI) determination. On the whole, fifteen Gram-positive bacterial strains (MRSA/ARSA) were used. Negative control …

Nanotopography Influences Adhesion, Spreading, And Self-Renewal Of Human Embryonic Stem Cells, Weiqiang Chen, Luis G. Villa-Diaz, Yubing Sun, Shinuo Weng, Jin Koo Kim, Raymond H. W. Lam, Lin Han, Rong Fan, Paul H. Krebsbach, Jianping Fu

Weiqiang Chen

Human embryonic stem cells (hESCs) have great potentials for future cell-based therapeutics. However, their mechanosensitivity to biophysical signals from the cellular microenvironment is not well characterized. Here we introduced an effective microfabrication strategy for accurate control and patterning of nanoroughness on glass surfaces. Our results demonstrated that nanotopography could provide a potent regulatory signal over different hESC behaviors, including cell morphology, adhesion, proliferation, clonal expansion, and self-renewal. Our results indicated that topological sensing of hESCs might include feedback regulation involving mechanosensory integrin-mediated cell matrix adhesion, myosin II, and E-cadherin. Our results also demonstrated that cellular responses to nanotopography were cell-type …

Bacteriocin Formation By Dominant Aerobic Sporeformers Isolated From Traditional Maari, Donatien Kabore, Line Thorsen, Dennis Sandris Nielsen, Torben Sune Berner, Hagrétou Sawadogo-Lingani, Bréhima Diawara, Mamoudou H. Dicko Prof., Mogens Jackobsen

Pr. Mamoudou H. DICKO, PhD

The antimicrobial activity of 8 Bacillus spp. and 2 Lysinibacillus spp. representing the predominant aerobic sporeformers during traditional maari fermentations, a traditional fermented baobab seeds product fromBurkina Faso,was investigated. The antimicrobial activitywas assessed against a total of 31 indicator organisms representing various Gram-negative and positive pathogens. The screening showed that 3 Bacillus subtilis strains (B3, B122 and B222) in particular had antimicrobial activity against some Gram-positive organisms and were selected for further studies. Itwas found that the antimicrobial substances producedwere heat stable, in-sensitive to catalase, sensitive to protease and trypsin but resistant to the proteolytic action of papain and proteinase …

Acid Resistance, Bile Tolerance And Antimicrobial Properties Of Dominant Lactic Acid Bacteria Isolated From Traditional “Maari” Baobab Seeds Fermented Condiment, Donatien Kabore, Hagrétou Sawadogo-Lingani, Mamoudou H. Dicko Prof., Bréhima Diawara, Mogens Jacobsen

Pr. Mamoudou H. DICKO, PhD

Maari is a fermented food condiment obtained by spontaneous fermentation of seeds from the baobab tree (Adansonia digitata). Nine dominant lactic acid bacteria (LAB) strains, isolated from traditional maari fermentation were examined for their resistance to pH 2.5, their tolerance to 0.3% bile and their antimicrobial activities against pathogenic bacteria. The agar spot test was used to screen the dominant LAB for antagonistic activity against a total of 21 indicator organisms including Bacillus cereus strains, Salmonella spp., Listeria monocytogenes, Yersinia enterocolitica, Escherichia coli and Micrococcus luteus. It was observed that all LAB strains survived in 0.3% bile and exhibited antimicrobial …

Mox/Cnts Hetero-Structures For Gas Sensing Applications: Role Of Cnts Defects, G. Neri, S. G. Leonardi, N. Donato, C. Marichy, Jean-Philippe Tessonnier, M.-G. Willinger, Kyeong-Hwan Lee, N. Pinna

Jean-Philippe Tessonnier

The preparation, characterization and sensing properties of CNT composites with a thin metal oxide (MOx) surface layer is presented. Atomic layer deposition (ALD) was applied for the coating of the inner and outer CNTs walls with thin films of ZnO and SnO2 of precisely controlled thicknesses. Differently treated CNTs with different degree of surface functionalization were used as support for the oxide films. The sensing properties of the obtained composite materials towards NO2 were investigated and related to the morphological and microstructural characteristics of both the coating and support. SnO2-based composites on CNTs treated at 700 °C show enhanced performance …

Labeling And Monitoring The Distribution Of Anchoring Sites On Functionalized Cnts By Atomic Layer Deposition, Catherine Marichy, Jean-Philippe Tessonnier, Marta C. Ferro, Kyeong-Hwan Lee, Robert Schlogl, Nicola Pinna, Marc-Georg Willinger

Jean-Philippe Tessonnier

The chemical inertness of graphite and, in the case of tubes, of rolled up few layer graphene sheets, requires some degree of "defect engineering" for the fabrication of carbon based heterostructured materials. It is shown that atomic layer deposition provides a means to specifically label anchoring sites and can be used to characterize the surface functionality of differently treated carbon nanotubes. Direct observation of deposited titania by analytical transmission electron microscopy reveals the location and density of anchoring sites as well as structure related concentrations of functional groups on the surface of the tubes. Controlled functionalization of the tubes therefore …

A Review Of Baobab (Adansonia Digitata) Products: Effect Of Processing Techniques, Medicinal Properties And Uses, Donatien Kabore, Hagrétou Sawadogo-Lingani, Bréhima Diawara, Clarise Compaoré, Mamoudou H. Dicko Prof., Mogens Jacobsen

Pr. Mamoudou H. DICKO, PhD

A general literature review including the effect of processing techniques, medicinal value and uses of baobab tree is reported in this manuscript. Baobab tree has multi-purpose uses, as it produces food and non-food products such as medicines, fuel, timber, fodder. Every part of the baobab tree is reported to be useful. The seeds, leaves, roots, flowers, fruit pulp and bark of baobab are edible. Baobab leaves are used in the preparation of soup. Seeds are used as a thickening agent in soups, but they can be fermented and used as a flavouring agent or roasted and eaten as snacks. The …

Photolithographic Surface Micromachining Of Polydimethylsiloxane (Pdms), Weiqiang Chen, Raymond H. W. Lam, Jianping Fu

Weiqiang Chen

A major technical hurdle in microfluidics is the difficulty in achieving high fidelity lithographic patterning on polydimethylsiloxane (PDMS). Here, we report a simple yet highly precise and repeatable PDMS surface micromachining method using direct photolithography followed by reactive ion etching (RIE). Our method to achieve surface patterning of PDMS applied an O2 plasma treatment to PDMS to activate its surface to overcome the challenge of poor photoresist adhesion on PDMS for photolithography. Our photolithographic PDMS surface micromachining technique is compatible with conventional soft lithography techniques and other silicon-based surface and bulk micromachining methods. To illustrate the general application of our …