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Articles 1 - 16 of 16

Full-Text Articles in Physical Sciences and Mathematics

Printed Ionic-Covalent Entanglement Hydrogels From Carrageenan And An Epoxy Amine, Shannon Bakarich, Paul Balding, Robert Gorkin Iii, Geoffrey Spinks, Marc In Het Panhuis Jun 2015

Printed Ionic-Covalent Entanglement Hydrogels From Carrageenan And An Epoxy Amine, Shannon Bakarich, Paul Balding, Robert Gorkin Iii, Geoffrey Spinks, Marc In Het Panhuis

Robert Gorkin III

Carrageenan/epoxy amine ionic-covalent entanglement hydrogels were fabricated on a 3D printer. The thermal gel transition behaviour of the biopolymer kappa-carrageenan was exploited to fix the shape of the patterned ink until a covalent polymer network formed by epoxy amine addition chemistry. The printed hydrogels display a work of extension value of 1.4 ± 0.3 MJ m-3.


Capacitive Behavior Of Latex/Single-Wall Carbon Nanotube Stretchable Electrodes, Hyeon Taek Jeong, Byung Kim, Robert Gorkin Iii, Michael J. Higgins, Gordon G. Wallace Jun 2015

Capacitive Behavior Of Latex/Single-Wall Carbon Nanotube Stretchable Electrodes, Hyeon Taek Jeong, Byung Kim, Robert Gorkin Iii, Michael J. Higgins, Gordon G. Wallace

Robert Gorkin III

In this report single-wall carbon nanotubes (SWNTs) were coated onto latex using spray coating to produce a stretchable electrode. The electrochemical properties of the electrode were determined using cyclic voltammetry and electrochemical impedance spectroscopy and galvanostatic charge/discharge tests were also carried out. The impedance and charge/discharge curves of the latex/SWNTs electrode showed good capacitive behavior even after repetitive stretching to 100% strain. The highest capacitance value obtained for the unstretched SWNTs electrode was 119 F g−1 in 1 M Na2SO4 at 5 mV s−1. After the 100th stretch ≈ 80% of the original capacitance value was retained.


Three-Dimensional Printing Fiber Reinforced Hydrogel Composites, Shannon Bakarich, Robert Gorkin Iii, Marc In Het Panhuis, Geoffrey Spinks Jun 2015

Three-Dimensional Printing Fiber Reinforced Hydrogel Composites, Shannon Bakarich, Robert Gorkin Iii, Marc In Het Panhuis, Geoffrey Spinks

Robert Gorkin III

An additive manufacturing process that combines digital modeling and 3D printing was used to prepare fiber reinforced hydrogels in a single-step process. The composite materials were fabricated by selectively pattering a combination of alginate/acrylamide gel precursor solution and an epoxy based UV-curable adhesive (Emax 904 Gel-SC) with an extrusion printer. UV irradiation was used to cure the two inks into a single composite material. Spatial control of fiber distribution within the digital models allowed for the fabrication of a series of materials with a spectrum of swelling behavior and mechanical properties with physical characteristics ranging from soft and wet to …


Poly(3,4-Ethylenedioxythiophene): Dextran Sulfate (Pedot: Ds) - A Highly Processable Conductive Organic Biopolymer, David Harman, Robert Gorkin Iii, Leo Stevens, Brianna Thompson, Klaudia Wagner, Bo Weng, Johnson Chung, Marc In Het Panhuis, Gordon Wallace Jun 2015

Poly(3,4-Ethylenedioxythiophene): Dextran Sulfate (Pedot: Ds) - A Highly Processable Conductive Organic Biopolymer, David Harman, Robert Gorkin Iii, Leo Stevens, Brianna Thompson, Klaudia Wagner, Bo Weng, Johnson Chung, Marc In Het Panhuis, Gordon Wallace

Robert Gorkin III

A novel water-dispersible conducting polymer analogous to poly(3,4-dioxythiophene):polystyrene sulfonate (PEDOT:PSS) has been chemically synthesized in a single reaction in high yield. PEDOT:DS, a new member of the polythiophene family, is composed of a complex between PEDOT and the sulfonated polysaccharide polyanion dextran sulfate. Drop-cast films of aqueous suspensions of the material display a native conductivity of up to 7 ± 1 S cm-1, increasing to 20 ± 2 S cm-1 after treatment with ethylene glycol and thermal annealing. Mass ratios of the precursors NaDS and EDOT were varied from 5:1 to 2:1 and a decrease in the NaDS:EDOT ratio produces …


Fluidic Automation Of Nitrate And Nitrite Bioassays In Whole Blood By Dissolvable-Film Based Centrifugo-Pneumatic Actuation, Charles E. Nwankire, Di-Sien S. Chan, Jennifer Gaughran, Robert Burger, Robert A. Gorkin Iii, Jens Ducree Jun 2015

Fluidic Automation Of Nitrate And Nitrite Bioassays In Whole Blood By Dissolvable-Film Based Centrifugo-Pneumatic Actuation, Charles E. Nwankire, Di-Sien S. Chan, Jennifer Gaughran, Robert Burger, Robert A. Gorkin Iii, Jens Ducree

Robert Gorkin III

This paper demonstrates the full centrifugal microfluidic integration and automation of all liquid handling steps of a 7-step fluorescence-linked immunosorbent assay (FLISA) for quantifying nitrate and nitrite levels in whole blood within about 15 min. The assay protocol encompasses the extraction of metered plasma, the controlled release of sample and reagents (enzymes, co-factors and fluorescent labels), and incubation and detection steps. Flow control is implemented by a rotationally actuated dissolvable film (DF) valving scheme. In the valves, the burst pressure is primarily determined by the radial position, geometry and volume of the valve chamber and its inlet channel and can …


The Ultimate Iron Chef - When 3d Printers Invade The Kitchen, Robert Gorkin Iii, Susan Dodds Jun 2015

The Ultimate Iron Chef - When 3d Printers Invade The Kitchen, Robert Gorkin Iii, Susan Dodds

Robert Gorkin III

Printing food seems more like an idea based in Star Trek rather than in the average home. But recent advances in 3D printing (known formally as additive manufacturing) are driving the concept closer to reality. With everything from printed metal airplane wings to replacement organs on the horizon, could printed food be next? And how will we feel when it's served at the table?


An Integrated Centrifugo-Opto-Microfluidic Platform For Arraying, Analysis, Identification And Manipulation Of Individual Cells, Robert Burger, D Kurzbuch, Robert Gorkin Iii, Gregor Kijanka, Macdara Glynn, C Mcdonagh, Jens Ducree Jun 2015

An Integrated Centrifugo-Opto-Microfluidic Platform For Arraying, Analysis, Identification And Manipulation Of Individual Cells, Robert Burger, D Kurzbuch, Robert Gorkin Iii, Gregor Kijanka, Macdara Glynn, C Mcdonagh, Jens Ducree

Robert Gorkin III

In this work we present a centrifugal microfluidic system enabling highly efficient collective trapping and alignment of particles such as microbeads and cells, their multi-colour fluorescent detection and subsequent manipulation by optical tweezers. We demonstrate array-based capture and imaging followed by "cherry-picking" of individual particles, first for fluorescently labelled polystyrene (PS) beads and then for cells. Different cell lines are discriminated based on intracellular as well as surface-based markers.


Strong Tough Gels For 3d Tissue Constructs, Paul Calvert, Marc In Het Panhuis, Geoffrey Spinks, Robert Gorkin Iii, Leo Stevens, Shannon E. Bakarich, Paul Balding, Damian M. Kirchmajer Jun 2015

Strong Tough Gels For 3d Tissue Constructs, Paul Calvert, Marc In Het Panhuis, Geoffrey Spinks, Robert Gorkin Iii, Leo Stevens, Shannon E. Bakarich, Paul Balding, Damian M. Kirchmajer

Robert Gorkin III

The mechanical characteristics of ionic-covalent entanglement hydrogels consisting of combinations of the biopolymers gellan gum and kappa-carrageenan, and the synthetic polymers polyacrylamide and an epoxy amine were investigated. Compression testing showed that these gels exhibited "double network" behavior, i.e. strong tough gels.


Graphene Oxide Dispersions: Tuning Rheology To Enable Fabrication, Sina Naficy, Rouhollah Jalili, Seyed Hamed Aboutalebi, Robert A. Gorkin Iii, Konstantin Konstantinov, Peter C. Innis, Geoffrey M. Spinks, Philippe Poulin, Gordon G. Wallace Jun 2015

Graphene Oxide Dispersions: Tuning Rheology To Enable Fabrication, Sina Naficy, Rouhollah Jalili, Seyed Hamed Aboutalebi, Robert A. Gorkin Iii, Konstantin Konstantinov, Peter C. Innis, Geoffrey M. Spinks, Philippe Poulin, Gordon G. Wallace

Robert Gorkin III

Here, we show that graphene oxide (GO) dispersions exhibit unique viscoelastic properties, making them a new class of soft materials. The fundamental insights accrued here provide the basis for the development of fabrication protocols for these two-dimensional soft materials, in a diverse array of processing techniques.


Optical Sensing System Based On Wireless Paired Emitter Detector Diode Device And Ionogels For Lab-On-A-Disc Water Quality Analysis, Monika Czugala, Robert Gorkin Iii, Thomas Phelan, Jennifer Gaughran, Vincenzo Curto, Jens Ducree, Dermot Diamond, Fernando Benito-Lopez Jun 2015

Optical Sensing System Based On Wireless Paired Emitter Detector Diode Device And Ionogels For Lab-On-A-Disc Water Quality Analysis, Monika Czugala, Robert Gorkin Iii, Thomas Phelan, Jennifer Gaughran, Vincenzo Curto, Jens Ducree, Dermot Diamond, Fernando Benito-Lopez

Robert Gorkin III

This work describes the first use of a wireless paired emitter detector diode device (PEDD) as an optical sensor for water quality monitoring in a lab-on-a-disc device. The microfluidic platform, based on an ionogel sensing area combined with a low-cost optical sensor, is applied for quantitative pH and qualitative turbidity monitoring of water samples at point-of-need. The autonomous capabilities of the PEDD system, combined with the portability and wireless communication of the full device, provide the flexibility needed for on-site water testing. Water samples from local fresh and brackish sources were successfully analysed using the device, showing very good correlation …


Design And Fabrication Of A Cop-Based Microfluidic Chip: Chronoamperometric Detection Of Troponin T, Llibertat Abad, Francisco Javier Del Campo, Francesc Xavier Munoz, Luis J Fernandez, Daniel Calavia, Gloria Colom, Juan P Salvador, Maria Pilar Marco, Vanessa Escamilla-Gomez, Berta Esteban-Fernandez De Avila, Susana Campuzano, Maria Pedrero, Jose M Pingarron, Neus Godino, Robert Gorkin Iii, Jens Ducree Jun 2015

Design And Fabrication Of A Cop-Based Microfluidic Chip: Chronoamperometric Detection Of Troponin T, Llibertat Abad, Francisco Javier Del Campo, Francesc Xavier Munoz, Luis J Fernandez, Daniel Calavia, Gloria Colom, Juan P Salvador, Maria Pilar Marco, Vanessa Escamilla-Gomez, Berta Esteban-Fernandez De Avila, Susana Campuzano, Maria Pedrero, Jose M Pingarron, Neus Godino, Robert Gorkin Iii, Jens Ducree

Robert Gorkin III

This work demonstrates the design and fabrication of an all cyclo-olefin polymer based microfluidic device capable of capturing magnetic beads and performing electrochemical detection in a series of gold electrodes. The size of chip is of a microscope slide and features six independent measuring cells formultianalyte detection purposes. The aim of this work is to show that rapid prototyping techniques can be instrumental in the development of novel bioassays, particularly in clinical diagnosis applications. We show the successful determination of troponin-T, a cardiac disease marker, in the clinically relevant range of 0.05–1.0 ng/mL. This methodology achieves a detection limit of …


Three Dimensional (3d) Printed Electrodes For Interdigitated Supercapacitors, Chen Zhao, Caiyun Wang, Robert Gorkin Iii, Stephen Beirne, Kewei Shu, Gordon Wallace Jun 2015

Three Dimensional (3d) Printed Electrodes For Interdigitated Supercapacitors, Chen Zhao, Caiyun Wang, Robert Gorkin Iii, Stephen Beirne, Kewei Shu, Gordon Wallace

Robert Gorkin III

Common fabrication techniques typically require multiple and complex MEMS processing steps to create 3D electrode architectures. Here we report on the use of Additive Fabrication metal printing based on Selective Laser Melting (SLM) technology to produce 3D titanium interdigitated electrodes. This was used as a platform to deposit polypyrrole and the resultant structure was evaluated for use as a capacitive electrode. We also demonstrate a solid-state interdigitated supercapacitor using a poly(vinyl alcohol) (PVA)-H3PO4 polymer electrolyte.


Fabricating Electrodes For Amperometric Detection In Hybrid Paper/Polymer Lab-On-A-Chip Devices, Neus Godino, Robert Gorkin Iii, Ken Bourke, Jens Ducree Jun 2015

Fabricating Electrodes For Amperometric Detection In Hybrid Paper/Polymer Lab-On-A-Chip Devices, Neus Godino, Robert Gorkin Iii, Ken Bourke, Jens Ducree

Robert Gorkin III

We present a novel, low-resource fabrication and assembly method for creating disposable amperometric detectors in hybrid paper-polymer devices. Currently, mere paper-based microfluidics is far from being able to achieve the same level of process control and integration as state-of-the-art microfluidic devices made of polymers. To overcome this limitation, in this work both substrate types are synergistically combined through a hybrid, multi-component/multi-material system assembly. Using established inkjet wax printing, we transform the paper into a profoundly hydrophobic substrate in order to create carbon electrodes which are simply patterned from carbon inks via custom made adhesive stencils. By virtue of the compressibility …


Centrifugo-Pneumatic Valving Utilizing Dissolvable Films, Robert Gorkin Iii, Charles Nwankire, Jennifer Gaughran, Xin Zhang, Gerard Donohoe, Martha Rook, Richard O'Kennedy, Jens Ducree Jun 2015

Centrifugo-Pneumatic Valving Utilizing Dissolvable Films, Robert Gorkin Iii, Charles Nwankire, Jennifer Gaughran, Xin Zhang, Gerard Donohoe, Martha Rook, Richard O'Kennedy, Jens Ducree

Robert Gorkin III

In this article we introduce a novel technology that utilizes specialized water dissolvable thin films for valving in centrifugal microfluidic systems. In previous work (William Meathrel and Cathy Moritz, IVD Technologies, 2007), dissolvable films (DFs) have been assembled in laminar flow devices to form efficient sacrificial valves where DFs simply open by direct contact with liquid. Here, we build on the original DF valving scheme to leverage sophisticated, merely rotationally actuated vapour barriers and flow control for enabling comprehensive assay integration with low-complexity instrumentation on "lab-on-a-disc" platforms. The advanced sacrificial valving function is achieved by creating an inverted gas-liquid stack …


Centrifugal Automation Of A Triglyceride Bioassay On A Low-Cost Hybrid Paper-Polymer Device, Neus Godino, Elizaveta Vereshchagina, Robert Gorkin Iii, Jens Ducree Jun 2015

Centrifugal Automation Of A Triglyceride Bioassay On A Low-Cost Hybrid Paper-Polymer Device, Neus Godino, Elizaveta Vereshchagina, Robert Gorkin Iii, Jens Ducree

Robert Gorkin III

We present a novel paper-polymer hybrid construct for the simple automation of fundamental microfluidic operations in a lab-on-a-disc platform. The novel design, we term a paper siphon, consists of chromatographic paper strips embedded along a siphon microchannel. The paper siphon relies on two main interplaying forces to create unique valving and liquid-sampling methods in centrifugal microfluidics. At sufficiently low speeds, the inherent wicking of the paper overcomes the rotationally induced centrifugal force to drive liquids towards inwards positions of the disc. At elevated speeds, the dominant centrifugal force will extract liquid from the siphon paper strip towards the edge of …


Centrifugal Microfluidics For Cell Analysis, Robert Burger, Daniel Kirby, Macdara Glynn, Charles E Nwankire, Mary O'Sullivan, Jonathan Siegrist, David Kinahan, Gerson Aguirre, Gregor Kijanka, Robert Gorkin Iii, Jens Ducree Jun 2015

Centrifugal Microfluidics For Cell Analysis, Robert Burger, Daniel Kirby, Macdara Glynn, Charles E Nwankire, Mary O'Sullivan, Jonathan Siegrist, David Kinahan, Gerson Aguirre, Gregor Kijanka, Robert Gorkin Iii, Jens Ducree

Robert Gorkin III

Over the past two decades, centrifugal microfluidic systems have successfully demonstrated their capability for robust, high-performance liquid handling to enable modular, multipurpose lab-on-a-chip platforms for a wide range of lifescience applications. Beyond the handling of homogeneous liquids, the unique, rotationally controlled centrifugal actuation has proven to be specifically advantageous for performing cell and particle handling and assays. In this review we discuss technologies to implement two important steps for cell handling, namely separation and capturing/counting.