Lynam C, Jennings K, Nolan K, Kane P, McKervey MA, Diamond D (2002) Tuning and enhancing enantioselective quenching of calixarene hosts by chiral guest amines., Anal Chem 74 (1) pp. 59-66
The synthesis of a propranolol amide derivative of p-allylcalixarene is described, which has been designed to behave as a molecular sensor capable of distinguishing chiral amines on the basis of their shape and chirality. This molecule can discriminate between the enantiomers of phenylalaninol through the quenching of the fluorescence emission in methanol in contrast to an (S)-dinaphthylprolinol calixarene derivative, which can discriminate between the enantiomers of phenylglycinol, but not phenylalaninol. The separation between the naphthyl fluorophores and the hydrogen-bonding sites within the chiral cavity can be tuned to recognize guest amines with similar separation between aryl groups and hydrogen-bonding sites. The formation of metal ion complexes of the p-allylcalixarene propranolol amide derivative is shown to induce a more regular and rigid cone conformation in the calixarene macrocycle, which generates a significant enhancement in the observed enantiomeric discrimination.
Viguier C, Crean C, O'Kennedy R (2012) Trends and perspectives in immunosensors, pp. 184-208
Immunosensors are devices that comprise both a biomolecular recognition system, such as an antibody and its corresponding antigen, and a transducer to translate the high affinity and specific binding event into a physical signal. Antibodies are produced by an immunological response to the presence of a foreign substance called an antigen. Antibodies may be immobilised onto a variety of platforms including bulk planar surfaces and nanoparticles by either covalent or adsorption strategies. Different interfaces between the biocomponents and the detector are available to monitor in 'real-time' the signal generated by biological interactions. The transducers detect, for example, the change in electron transfer, absorbance, fluorescence, refractive index, mass change or heat transfer as the antibody binds to the antigen of interest. Such analytical devices have allowed a wide range of analytes to be identified and quantified such as pathogens, toxins, environmental food contaminants and disease biomarkers. The demand for sensitive, rapid, and 'on-site' techniques has taken advantage of the latest advances in microfluidics and nanotechnology. This chapter will highlight current trends in immobilisation, micro/nano-fluidics/and transducers utilised. A number of examples outlining the exploitation of these elements in immunosensors and their successful applications will be described. © 2012 Bentham Science Publishers. All rights reserved.
Chen J, Wang JZ, Minett AI, Liu Y, Lynam C, Liu H, Wallace GG (2009) Carbon nanotube network modified carbon fibre paper for Li-ion batteries, ENERGY & ENVIRONMENTAL SCIENCE 2 (4) pp. 393-396 ROYAL SOC CHEMISTRY
Wallace GG, Ngamna O, Moulton S, Lynam C (2005) Use of carbon nanotubes in modifying the properties of inherently conducting polymers, Meeting Abstracts pp. 377-377
Chen J, Minett AI, Liu Y, Lynam C, Sherrell P, Wang C, Wallace GG (2008) Direct growth of flexible carbon nanotube electrodes, ADVANCED MATERIALS 20 (3) pp. 566-+ WILEY-V C H VERLAG GMBH
Dechakiatkrai C, Chen J, Lynam C, Wetchakul N, Phanichphant S, Wallace GG (2009) Direct growth of carbon nanotubes onto titanium dioxide nanoparticles., J Nanosci Nanotechnol 9 (2) pp. 955-959
Multi-wall carbon nanotubes (MWNTs) were successfully deposited on a TiO2 nanoparticle film via thermal chemical vapour deposition (CVD) using iron(III) as the catalyst, which was loaded into the titanium isopropoxide precursor solution. The properties of the TiO2/MWNTs nanocomposite was characterized using Raman spectroscopy, scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDX), 4-point probe conductivity measurements and cyclic voltammetry. Preliminary investigations on this TiO2/MWNTs nanocomposite as an anode material for Li-ion batteries shows a high reversible capacity of 268 mAh g(-1) with improved cycling stability compared with a mechanically blended composite.
Using facile diazonium chemistry, sulfonate groups have been covalently attached to single wall carbon nanotubes. The resulting sulfonated tubes form a stable aqueous dispersion in the presence of pyrrole monomer. Subsequent electropolymerisation results in a conductive, electroactive polypyrrole doped with sulfonated tubes being formed at unusually low potentials. The potential of this material as a host matrix for biomolecules has been demonstrated by entrapping horse-radish peroxidase directly in the polypyrrole during composite formation.
Moore CJ, Montón H, O'Kennedy R, Williams DE, Nogués C, Crean C, Gubala V (2015) Controlling colloidal stability of silica nanoparticles during bioconjugation reactions with proteins and improving their longer-term stability, handling and storage, Journal of Materials Chemistry B 3 (10) pp. 2043-2055 The Royal Society of Chemistry
Despite the potential of antibody-coated nanoparticles (Ab-NPs) in many biological applications, there are very few successful, commercially available examples in which the carefully engineered nanomaterial has made it beyond the laboratory bench. Herein we explore the robustness and cost of protein-nanoparticle conjugation. Using multivalent polyamidoamine (PAMAM) dendrimers and dextran as crosslinkers, it was possible to retain colloidal stability during (i) NP-linker binding and (ii) the subsequent conjugation reaction between linker-coated NPs and proteins to generate monodisperse Ab-NPs. This was attributed to the physicochemical properties of the linkers, which were inherited by the NPs and thus benefited colloidal stability. Attaching negatively charged, EDC/sulfo-NHS-activated PAMAM to the NPs contributed to overall negative charge of particles, and in turn led to high electrostatic attraction between the protein and PAMAM-coated NPs during the reaction conditions. In contrast, using an uncharged, EDC/NHS-activated PAMAM dendrimer led to NP aggregation and lower protein binding efficiency. Dextran as a cost-effective, uncharged macromolecule allowed for steric repulsions between neighbouring particles during protein binding, thus inducing NP stability in solution, and also produced monodisperse Ab-NPs. By freeze-drying Ab-NPs from a 1% BSA solution it is possible to reconstitute the solid-form colloid back to a stable state by adding solvent and simply shaking the sample vial by hand. The consequences of the different surface chemistries and freeze-drying stabilizers on the colloidal stability of the NPs were probed by dynamic light scattering. The performance of Ab-NPs was compared in a simple fluorescence linked immunoassay in whole serum. Interestingly, the signal-to-noise ratios were similar for Ab-NPs using PAMAM and dextran, despite dextran binding fewer Abs per NP. We believe this work provides researchers with the tools and strategies for reliably generating Ab-NPs that can be used for a variety of biological applications.
Pringle JM, Winther-Jensen O, Lynam C, Wallace GG, Forsyth M, MacFarlane DR (2008) I&EC 70-Ionic liquids for the synthesis of conducting polymer-noble metal nanocomposites, ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY 236 AMER CHEMICAL SOC
Gilmartin N, Crean C (2014) Nanoparticle technologies in detection science, RSC Detection Science 2014-January (3) pp. 116-141
The growing need for analytical devices requiring smaller sample volumes, decreased power consumption and improved performance have been driving forces behind the rapid growth in nanomaterials research. Due to their dimensions, nanostructured materials display unique properties not traditionally observed in bulk materials. Characteristics such as increased surface area along with enhanced electrical/optical properties make them suitable for numerous applications such as nanoelectronics, photovoltaics and chemical/biological sensing. In this review we examine the potential that exists to use nanostructured materials for biosensor devices. By incorporating nanomaterials, it is possible to achieve enhanced sensitivity, improved response time and smaller size. Here we report some of the success that has been achieved in this area. Many nanoparticle and nanofibre geometries are particularly relevant, but in this paper we specifically focus on organic nanostructures, reviewing conducting polymer nanostructures and carbon nanotubes.
Pringle JM, Winther-Jensen O, Lynam C, Wallace GG, Forsyth M, MacFarlane DR (2008) PMSE 431-Nanostructured conducting polymer synthesis in ionic liquids, ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY 236 AMER CHEMICAL SOC
Li WH, Lynam C, Chen J, Liu B, Zhang XZ, Wallace GG (2007) Magnetorheology of single-walled nanotube dispersions, MATERIALS LETTERS 61 (14-15) pp. 3116-3118 ELSEVIER SCIENCE BV
Dechakiatkrai C, Lynam C, Chen J, Phanichphant S, Wallace GG (2008) Characterisation of Titanium Dioxide-Single Walled Carbon Nanotubes Composite Fibres Prepared by the Wet Spinning Technique, 2008 2ND IEEE INTERNATIONAL NANOELECTRONICS CONFERENCE, VOLS 1-3 pp. 134-139 IEEE
In this article, we report on poly(amidoamine) dendrimers (PAMAM) as coupling agents for recombinant single-chain (ScFv) antibodies to nanoparticle (NP) labels, for use in immunoassay. We present a simple theory for the kinetics of particle capture onto a surface by means of an antibody?antigen reaction, in which the important parameter is the fraction of the particle surface that is active for reaction. We describe how increasing the generation number of the linking dendrimers significantly increased the fraction of the NP surface that is active for antigen binding and consequently also increased the assay kinetic rates. Use of dendrimers for conjugation of the NP to the antibody resulted in a significantly higher surface coverage of active antibody, in comparison with mono-valent linker chemistry. As a direct consequence, the increase in effective avidity significantly out-weighed any effect of a decreased diffusion coefficient due to the NP, when compared to that of a molecular dye-labelled antibody. The signal to noise ratio of the G4.5 dendrimer-sensitised nanoparticles out-performed the dye-labelled antibody by approximately four-fold. Particle aggregation experiments with the multi-valent antigen CRP demonstrated reaction-limited aggregation whose rate increased significantly with increasing generation number of the dendrimer linker.
Lynam C, Minett AI, Habas SE, Gambhir S, Officer DL, Wallace GG (2008) Functionalising carbon nanotubes, INT J NANOTECHNOL 5 (2-3) pp. 331-351
INDERSCIENCE ENTERPRISES LTD
Pringle JM, Ngamna O, Lynam C, Wallace GG, Forsyth M, MacFarlane DR (2007) Conducting polymers with fibrillar morphology synthesized in a biphasic ionic liquid/water system, MACROMOLECULES 40 (8) pp. 2702-2711 AMER CHEMICAL SOC
Over the past decade, the design and development of wearable sensors for biomedical applications has garnered considerable attention in the scientifi c community and in industry. This chapter aims to review research conducted into wearable sensors for healthcare monitoring. Acceptance of this approach in observation of physiological data depends strongly on the cost, wearability, usability and performance of such devices. An outline of body sensor network systems (and applications of wearable computing devices) is provided with a summary of electronic textiles. A synopsis of the clinical applications of this type of technology is given at the end of the chapter © 2012 Woodhead Publishing Limited All rights reserved.
Dechakiatkrai C, Lynam C, Gilmore KJ, Chen J, Phanichphant S, Bavykin DV, Walsh FC, Wallace GG (2009) Single-Walled Carbon Nanotube/Trititanate Nanotube Composite Fibers, ADVANCED ENGINEERING MATERIALS 11 (7) pp. B55-B60 WILEY-V C H VERLAG GMBH
Pringle JM, Forsyth M, MacFarlane DR, Winther-Jensen O, Lynam C, Wallace GG (2008) One-step synthesis of conducting polymer-noble metal nanoparticle composites using an ionic liquid, Advanced Functional Materials 18 (14) pp. 2031-2040
Conducting polymers containing incorporated gold or silver nanoparticles have been synthesized using ionic liquid solutions of gold chloride or silver nitrate. Use of the metal salts as the oxidant for monomers such as pyrrole and terthiophene allows the composites to be formed in one simple step, without the need for templates or capping agents. The incorporated metal nanoparticles are clearly visible by TEM, and the composites have been further analyzed by TGA, CV, UV-Vis, Raman, XPS and scanning TEM coupled with EDS analysis. Utilization of an ionic liquid allows the full oxidizing power of the gold chloride to be accessed, resulting in incorporation of metallic gold into the polymers. © 2008 Wiley-VCH Verlag GmbH & Co. KGaA.
Lynam C, Moulton SE, Wallace GG (2007) Carbon-nanotube biofibers, ADVANCED MATERIALS 19 (9) pp. 1244-+ WILEY-V C H VERLAG GMBH
Sherrell PC, Chen J, Razal JM, Nevirkovets IP, Crean C, Wallace GG, Minett AI (2010) Advanced microwave-assisted production of hybrid electrodes for energy applications, ENERGY & ENVIRONMENTAL SCIENCE 3 (12) pp. 1979-1984 ROYAL SOC CHEMISTRY
Lee JW, Shin KM, Lynam C, Spinks GM, Wallace GG, Kim SJ (2008) The optimum functionalization of carbon nanotube/ferritin composites, SMART MATERIALS & STRUCTURES 17 (4) ARTN 045029 IOP PUBLISHING LTD
New energy storage devices are required to enable future technologies. With the rise of wearable consumer and medical devices, a suitable flexible and wearable means of storing electrical energy is required. Fibre-based devices present a possible method of achieving this aim. Fibres are inherently more flexible than their bulk counterparts, and as such can be employed to form the electrodes of flexible batteries and capacitors. They also present a facile possibility for incorporation into many fabrics and clothes, further boosting their potential for use in wearable devices.
Electrically conducting fibres were produced from a dispersion of carbon nanomaterials in a room temperature ionic liquid. Coagulation of this dispersion was achieved through manual injection into aqueous solutions of xanthan gum. The limitations of this method are highlighted by very low ultimate tensile strengths of these fibres, in the order of 3 MPa, with high variation within all of the fibres. Fibres were also produced via scrolling of bi-component films containing poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) and poly(vinyl alcohol) (PVA). Chemical treatments were employed to impart water compatibility to these fibres, and their electrochemical, physical and electrical properties were analysed.
Fibres were wet spun from two PEDOT:PSS sources, in several fibre diameters. The effect of chemical treatments on the fibres were investigated and compared. Short 5 min treatment times with dimethyl sulfoxide (DMSO) on 20 ¼m fibres produced from Clevios PH1000 were found to produce the best overall treatment. Up to a six-fold increase in electrical conductivity resulted, reaching 800 S cm-1, with up to 40 % increase in specific capacitance and no loss of mechanical strength (55 F g-1 and 150 MPa recorded).
A wet spinning system to produce PEDOT:PSS fibres containing functionalised graphenes and carbon nanotubes, as well as birnessite nanotubes was subsequently developed. Manganese dioxide was also grown electrochemically on the outside of PEDOT:PSS fibres, with polypyrrole and PEDOT:PSS coating protection methods investigated. Electrochemical testing determined that birnessite nanotube-containing fibres presented the most viable option for energy storage device applications. Using the birnessite nanotube-containing fibre, fibre-based supercapacitors were fabricated and investigated. Specific capacitance values of 80 F g-1 were obtained, stable for over 1,000 cycles
Multilayered flexible fibers, consisting of carbon black-carbon nanotube fibers, manganese oxides and conducting polymers, were fabricated for use as electrodes in supercapacitors. Carbon-based fibers were initially prepared by wet-spinning using carbon-based nanomaterials (carbon black and carbon nanotubes) and chitosan as a matrix. Subsequent coatings with manganese oxides and conducting polymers form a multilayered structure. Different MnO2 crystalline structures (µ-MnO2, ³-MnO2) were grown onto the fibre by electrodeposition and different conducting polymers (polyethylenedioxythiophene and polypyrrole) used as a conductive wrapping. Each layer improved the performance of the fibre by adding different functionalities. While MnO2 improved the capacitance of the fibre, the presence of conducting polymers creates a conductive network increasing the capacitance further and conferring cycling stability. Capacitance values up 600 F g-1 and capacitance retention of 90% can be achieved with these multilayered hybrid fibers. A symmetric supercapacitor device, prepared from two hybrid fibres showed no significant change in properties when the device was bent, demonstrating their potential in flexible electronic devices and wearable energy systems.
Flexible microcomponents are being widely employed in the microelectronic industry; however; they suffer from a lack of complex movement. To address this problem, we have developed flexible, electrically conductive, magnetic composite fibres showing complex motion in three dimensions with the capacity to be selectively actuated. Flexible carbon-based fibres were prepared by wet-spinning and were subsequently modified by electrodepositing Co-Ni. The high aspect ratio of the fibre (40 ¼m diameter, 3.5 cm length) causes a directional dependence in the magnetostatic energy, which will allow for anisotropic actuation of the composite. Thus, the application of magnetic fields allows for a precise control of the movement with high reproducibility and accuracy.
Flexible fibre supercapacitors were fabricated by wet-spinning from carbon nanotube/carbon black dispersions, followed by straightforward surface treatments to sequentially deposit MnO2 and PEDOT:PSS to make ternary composite fibres. Dip coating the fibres after the initial wet-spinning coagulation creates a simple solution-based continuous process to produce fibre-based energy storage. Well-controlled depositions were achieved and have been optimised at each stage to yield the highest specific capacitance. A single ternary composite fibre exhibited a specific capacitance of 351/F/g?1. Two ternary composite fibre electrodes were assembled together in a parallel solid-state device, with polyvinyl alcohol/H3PO4 gel used as both an electrolyte and a separator. The assembled flexible device exhibited a high specific capacitance of 51.3/F/g?1 with excellent both charge-discharge cycling (84.2% capacitance retention after 1000/cycles) and deformation cycling stability (82.1% capacitance retention after 1000 bending cycles).
This study used Raman spectro-microscopy to investigate the synthesis and degradation of radiation-grafted anion-exchange membranes (RG-AEM) made using 50 ¼m thick poly(ethylene-co-tetrafluoroethylene) (ETFE) films, vinylbenzyl chloride (VBC) monomer, and 1-methylpyrrolidine (MPY) amination agent. The data obtained confirmed the operation of the grafting-front mechanism. VBC grafting times of 1 and 4 h led to low degrees of grafting homogeneity, while 72 h led to extreme levels of grafting that resulted in mechanically weak RG-AEMs due to the excessive H2O contents. A grafting time of 16 h was optimal yielding a RG-AEM with an ion-exchange capacity (IEC) of 2.06 ± 0.02 mmol g-1 (n = 3). An excess of grafting was detected at the surface of this RG-AEM (at least within the first few ¼m of the surface). This RG-AEM was then degraded in O2-purged aqueous KOH (1.0 mol dm-3) for 14 d at 80 °C. Degradation was detected throughout the RG-AEM cross-section, where the Raman data was quantitatively consistent with the loss of IEC. A slight excess of degradation was detected at the surface of the RG-AEM. Degradation involved the loss of whole benzyl-1-methypyrrolidinium grafted units as well as the direct attack on the pendent (cationic) pyrrolidinium groups by the hydroxide anions.
A miniaturized, flexible fiber-based lithium sensor was fabricated from low-cost cotton using a simple, repeatable dip-coating technique. This lithium sensor is highly suited for ready-to-use wearable applications and can be used directly without the preconditioning steps normally required with traditional ion-selective electrodes. The sensor has a stable, rapid and accurate response over a wide Li+ concentration range that spans over the clinically effective and the toxic concentration limits for lithium in human serum. The sensor is selective to Li+ in human plasma even in the presence of a high concentration of Na+ ions. This novel sensor concept represents a significant advance in wearable sensor technology which will target lithium drug monitoring from under the skin.
This paper outlines preliminary work developing graphene modified thermoplastic inserts to be used for the toughening of CFRP. The paper outlines laminate
manufacture, mechanical testing and fracture analysis of graphene modified CFRP.