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Institute of Environmental Science & Research Ltd ESR | Date: 2015-05-26

Computer software for interpretation of DNA profiling results. Printed instructional and teaching material, not including apparatus, relating to computer software for interpretation of DNA profiling results.

Booth M.A.,University of Auckland | Harbison S.,Institute of Environmental Science & Research Ltd. ESR | Travas-Sejdic J.,University of Auckland | Travas-Sejdic J.,MacDiarmid Institute for Advanced Materials and Nanotechnology
Electroanalysis | Year: 2012

Much research-to-date exists to create sensitive and selective DNA sensors. A variety of approaches are adopted, including those involving polypyrrole and electrical impedance spectroscopy. Combined these are able to sense as well as aptly transduce signals. Many such sensors employ ferri/ferrocyanide to exhibit surface hybridization. This redox reporter, though with merits, can prove disadvantageous. To this end, a comparative study was performed with the redox reporter hydroquinone. For comparison purposes ferri/ferrocyanide indicated greater sensitivity, suggested to arise from inherent charge. Conversely, with hydroquinone steric hindrance is the main influencing factor. Such a study aims to guide design of analogous sensors. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Booth M.A.,University of Auckland | Booth M.A.,Institute of Environmental Science & Research Ltd. ESR | Harbison S.,Institute of Environmental Science & Research Ltd. ESR | Travas-Sejdic J.,Institute of Environmental Science & Research Ltd. ESR | Travas-Sejdic J.,MacDiarmid Institute for Advanced Materials and Nanotechnology
Biosensors and Bioelectronics | Year: 2011

DNA sensors have a wide scope of applications in the present and emerging medical and scientific fields, such as medical diagnostics and forensic investigations. However, much research-to-date on DNA sensor development has focused on short target DNA strands as model genes. In this communication we study the effect of the length of oligonucleotide probe and target strands as a significant step towards real world applications for DNA detection. The sensor technology described uses the conducting polymer polypyrrole as both a sensing element and transducer of sensing events - namely the hybridization of complementary target oligonucleotide to probe oligonucleotide. Detection is performed using electrical impedance spectroscopy. Initially sensor development is performed, wherein we demonstrate an improvement in stability and sensitivity as well as show a reduction in non-specific DNA binding for fabricated sensors, through use of a specific dopant and post-growth treatment. Subsequently, we show that longer target DNA strands display increased response, as do sensors containing longer probe DNA strands. It is suggested that these results are a feature of the increase in negative charges associated with the longer DNA strands. The results of this comparative study are aimed to guide future design of analogous sensors. © 2011 Elsevier B.V. Source

Adela Booth M.,University of Auckland | Adela Booth M.,Institute of Environmental Science & Research Ltd. ESR | Vogel R.,Izon Science Ltd. | Vogel R.,University of Queensland | And 4 more authors.
Biosensors and Bioelectronics | Year: 2013

Despite the plethora of DNA sensor platforms available, a portable, sensitive, selective and economic sensor able to rival current fluorescence-based techniques would find use in many applications. In this research, probe oligonucleotide-grafted particles are used to detect target DNA in solution through a resistive pulse nanopore detection technique. Using carbodiimide chemistry, functionalised probe DNA strands are attached to carboxylated dextran-based magnetic particles. Subsequent incubation with complementary target DNA yields a change in surface properties as the two DNA strands hybridize. Particle-by-particle analysis with resistive pulse sensing is performed to detect these changes. A variable pressure method allows identification of changes in the surface charge of particles. As proof-of-principle, we demonstrate that target hybridization is selectively detected at micromolar concentrations (nanomoles of target) using resistive pulse sensing, confirmed by fluorescence and phase analysis light scattering as complementary techniques. The advantages, feasibility and limitations of using resistive pulse sensing for sample analysis are discussed. © 2013 Elsevier B.V. Source

Booth M.A.,University of Auckland | Booth M.A.,Institute of Environmental Science & Research Ltd. ESR | Leveneur J.,University of Auckland | Leveneur J.,Institute of Geological & Nuclear Sciences | And 5 more authors.
Journal of Physical Chemistry C | Year: 2012

Low-energy platinum ions were implanted with 15 keV under normal incidence into synthesized conducting polymer films with the aim to improve film conductivity and to demonstrate the use of implanted platinum in a simple sensing design. Conductivity measurements, cyclic voltammetry, and Raman spectroscopy were performed on samples both before and following ion implantation. Results display an optimum fluence of ion implantation for which polypyrrole films implanted with 2 × 10 16 at. cm -2 display and retain enhanced conductivity compared with nonimplanted samples. X-ray photoelectron spectroscopy (XPS) and scanning electron microscope-energy-dispersive X-ray spectroscopy (SEM-EDS) confirmed that implanted platinum is present mainly as Pt 0 and indicated that the depth and amount of ion implantation are in agreement with a simulated implantation profile. Raman spectroscopy showed a surface-enhanced Raman spectroscopy (SERS) effect with platinum's presence. The advantageous increase in conductivity can be rationalized by two chemical modifications to the polymer upon high-fluence implantation: (1) an increase in the number of charge carriers (dications) within the polymer and (2) the presence of elemental platinum metal and its synergistic effect on conductivity. A simple DNA sensor was constructed on the basis of polypyrrole/Pt 0 films where Pt 0 was able to serve as anchoring points for DNA attachment as well as an enhancer of the film's conductivity. This enabled a DNA sensor capable of successful detection of cDNA, and a good discrimination of noncDNA, thus opening a way to direct electrochemical biosensing on the basis of ion implanted highly conducting polymer films. © 2012 American Chemical Society. Source

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