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Prof Emmanuel Iwuoha (2010)

Prof. Emmanuel I. Iwuoha is our invited  keynote speaker for the 27th October 2010.

NAME & QUALIFICATIONS: Professor Emmanuel I. Iwuoha (CSc, CChem, FRSC) – Fellow of the Royal Society of Chemistry, UK (since 2000); Chartered Chemist (RSC UK since 1990); Chartered Scientist (Science Council UK since 2004), Member American Chemical Society.

ADDRESS: Room 3.44 New Science Building, Department of Chemistry, University of Western Cape, Bellville  Tel: 27 21 959 3054; Fax: 27 21 959 1562; cell: 27 82 777 3350; e-mail: eiwuoha@uwc.ac.za ; Web page: http://academic.sun.ac.za/sensorlab (under construction).

Appointments

Prof Iwuoha is serving UWC in the following capacities: Professor and Chair of Physical Chemistry; Member UWC Council; Member UWC Executive Committee of the Council; Deputy Chairperson UWC Institutional Forum; Member UWC Senate; Member Senior Appointment Committee of Council, Member Joint Appointment Committee of Senate and Council; Member Risk Management Committee of Council; Member Faculty of Science Postgraduate Committee; Deputy Chairperson Department of Chemistry; Chairperson Chemistry Department Postgraduate Committee. Previously he served as Member Senate and Faculty of Science Assessment Committees, Member Rector’s Task Team and former Chairperson of the Institutional Forum.

Research Profile

Prof Emmanuel Iwuoha is an Electrochemist, the founder and leader of SensorLab; as well as the Research Niche Area Leader for the “Development of Catalytic Materials” under the National Research Foundation (NRF) Institutional Capacity Development (ICD) programme (made up of 24 academics and senior scientists); Chairperson of the Steering Committee of the Centre for Nanoscience at UWC.  SensorLab researchers for 2009 include 4 Chemistry Lecturers, 3 International Visiting Scientists, 7 Postdoctoral fellows, 17 PhD, 5 MSc students and 8 research assistants.  Research activities at the SensorLab involves the designing, synthesis and analysis of organic and inorganic electroactive ‘smart’ nanomaterials for the construction of energy-generating, photovoltaic and chemo- and bio-sensor electrocatalytic systems. Prof Iwuoha is a Guest Editor for Electrochimica Acta special issue on Sensors and Sensor Technology, Editorial Board member of five journals, reviews actively for 20+ journals on Sensors and Electrochemistry and has published widely in Electrochemistry, Nanomaterials and Sensors. He has collaborations with several Sensor and electrochemistry laboratories including Prof MR Smyth of the National Centre for Sensor Research, Dublin Ireland; Profs Christopher and Ana Brett of University of Coimbra Portugal; Prof S. Cosnier, CNRS Grenoble France; Prof A. Guiseppi-Elie of Centre for Biosensors, Bioelectronics and Biochips, Clemson University USA, Prof C. Osulivan, URV, Tarragona Spain; Dr G Malgas, Centre for Nanotechnology, CSIR Pretoria, Dr K. Ozoemena, CSIR Pretoria, etc. He has also given more than 150 conference presentations in 50+ countries and more than 120 publications.

Recent International Contract Studies

Performance of the First Greenhouse Inventory for the Republic of Trinidad and Tobago.

Co-author of Trinidad and Tobago’s First National Communication on Climate Change, under the United Nations Framework Convention on Climate Change (UNFCCC).

SensorLab Profile

LEADER: Prof Emmanuel Iwuoha                        CO-LEADER:    Prof Priscilla Baker

UWC STAFF TEAM DETAILS:    Prof Emmanuel Iwuoha, Prof Priscilla Baker, Dr Nazeem Jahed and Miss Rachel F. Ngece

Current Student Registration

Number of SensorLab PhD students in 2010: 17.

Number of SensorLab MSc students in 2010: 18.

Graduates (2007-2010)

Number of SensorLab PhD graduates: 11.

Number of SensorLab MSc graduates: 9.

Research Activities/ Focus

SensorLab is an electrochemistry, nanoscience and sensor research laboratory. The centre’s research focus involves the designing, synthesis and analysis of soft organic and hard inorganic electroactive ‘smart’ nanomaterials for application in the construction of electrocatalytic sensors and energy-generating systems. Immunosensors, genosensors (DNA sensors and aptamer sensors) and redox enzyme-based biosensors are constructed with dendrimeric and polymeric nanomaterials for applications in environmental and biomedical analysis. Associated research projects include therapeutic drug monitoring biosensors for anti-retroviral, anti-tuberculosis and anti-depressant drugs; immunosensors for mycotoxins in food products, biomarkers for cancers, drug resistant tuberculosis and other medical conditions; genosensors and nanobarcodes for DNA profiling; and aptamer sensor chips for endocrine disrupting compounds, polyaromatic hydrocarbons, persistent organic pollutants in water. The nanomaterials research activities focus on the development of catalytic nanomaterials, nanophase hexagonal alkoxy-polyanilines, poly(propylene imine)-polypyrrole/polythiophene conducting star copolymers, new generation bi-and tri-metallic nanoalloys and quantum dots for applications in sensor chip arrays, supercapacitors, photovoltaic cells, stable high performance composite electrodes and electronically-modulated optical devices.

Instrumentation

SensorLab has expertise and instrumentation for dynamic electrochemistry, electrochemical impedance spectroscopy, UV-Vis and subtractively normalized FTIR spectroelectrochemistry (SNIFTIR), AC and DC voltammetry, scanning electrochemical microscopy, multichannel and multi-electrode (12) automated simultaneous electrochemistry and electrochemical analysis. SensorLab is well equipped with instruments for electrochemical and sensor technology which include 16 electrochemical workstations made up of 4 BAS 100, 1 BAS 50, 2 Epsilon, 1 VoltaLab 80, 1 Amel 7050, 1 Zhaner IM6e (for electrochemical impedance spectroscopy, EIS), 1 Methrom Analyser, 1 PalmSens potable potentiostat, 1 PAR 273 coupled to PAR lock-in amplifier for high frequency studies, 1 PAR 370 scanning electrochemical microscope, SECM), 1 Uniscan TST-RM-12 and multichannel robotic electrochemical testing workstation. Our laboratory is also equipped for spectroelectrochemistry with Bruker FTIR specially designed for  (SNIFTIR), Nanolog for fluorescent spectrometry, GPC-HPLC 2-dimensional polymer station instrumentation and software for polymer size differentiation.

Selected Publications: 2007-2010

  1. E. I. Iwuoha, A. Al-Ahmed, M. Sekota, T. Waryo, P. Baker. Amperometric Sensors. In Encyclopedia of Supramolecular Chemistry (2007) Taylor & Francis, pp 1-18.
  2. E Iwuoha, F. Ngece, M. Klink, P Baker. Amperometric responses of CYP2D6 drug metabolism nanobiosensor for sertraline: a selective serotonin reuptake inhibitor. Nanobiotechnology (2007) 1: 62-67.
  3. T. Ashe, E. Alleyne, E. Iwuoha. Serum cytochrome C detection using a cytochrome C oxidase biosensor. Biotechnolgy and Applied Biochemistry (2007) 46: 185-189.
  4. J. H. O. Owino, A. Ignaszak, A. Al-Ahmed, P.G. L. Baker, H. Alemu, J. C. Ngila, E. I. Iwuoha; Modelling of the impedimetric responses of an aflatoxin B1
  5. A. Ignaszak, N. Hendricks, T.Waryo, E. Songa, N. Jahed, R. Ngece, A. Al-Ahmed, B. Kgarebe, P. Baker, E.I. Iwuoha. Novel therapeutic biosensor for indinavir—A protease inhibitor antiretroviral drug. Journal of Pharmaceutical and Biomedical Analysis (2009) 49: 498–501.
  6. A.O. Arotiba, E.A. Songa, P.G.L. Baker, E.I. Iwuoha. Dendrimeric gold-poly(propylene imine) electrochemical DNA nanobiosensor, Chemistry Today (2009) 27: 55-5821.
  7. E. A. Songa, O. A. Arotiba, J.H.O. Owino, N. Jahed, P.G.L. Baker, E.I. Iwuoha. Electrochemical detection of glyphosate herbicide using horseradish peroxidase immobilized on sulfonated polymer matrix, Bioelectrochemistry (2009) 75: 117-123.
  8. V. Somerset, J. Leaner, R. Mason, E. Iwuoha, A. Morrin. Development and application of a poly(2,2-dithiodianiline) (PDTDA) coated screen-printed carbon electrode in inorganic mercury determination. Electrochimica Acta, (2010) 55: 4240-4246.
  9. M. Muchindu, T. Waryo, O. Arotiba , E. Kazimierska, A. Morrin, A. J. Killard, M. R. Smyth, N. Jahed, B. Kgarebe, P. G.L. Baker, E. I. Iwuoha. Electrochemical nitrite nanosensor developed with amine- and sulphate-functionalised polystyrene latex beads self-assembled on polyaniline. Electrochimica Acta (2010) 55: 4274-4280.
  10. L. Petrik, P. Ndungu, E. Iwuoha. Hall measurements on carbon nanotube paper modified with electroless deposited platinum. Nanoscale Research Letters (2010) 5:38–47.
  11. P.M. Ndangili, O.A. Arotiba, P.G.L. Baker, E.I. Iwuoha. A potential masking approach in the detection of dopamine on 3-mercaptopropionic acid capped ZnSe quantum dots modified gold electrode in the presence of interferences, Journal of Electroanalytical Chemistry (2010) 643: 77-81.
  12. J. Martinovic, J. van Wyk, S. Mapolie, N. Jahed, P. Baker, E. Iwuoha Electrochemical and spectroscopic properties of dendritic cobalto-salicylaldiimine DNA biosensor, Electrochimica Acta (2010) 55: 4296-4302.

Major achievements
FIG 1. SensorLab soft nanomaterials

SNIFTIR of Polyaniline nanotubes

Dendriticstar polymers

Polyaniline nanorods

Polymeric-nanoclusters

·         Synthesis and electrochemical impedance spectroscopic modelling of dendritic poly(propylene imine) polypyrrole/polythiophene onducting star copolymers for applications in sensors, ultra capacitors and electronically modulated optical devices.

·         Development of a series of therapeutic drug monitoring nanobiosensors for protease inhibitor antiretroviral, selective serotonin re-uptake inhibitor and antituberculosis drugs.

·         Smart electroactive nanophase polyaromatic sulphonic acid-modulated polyanilines customized for application in the construction of photovoltaic cells and supercapcitors.

·         New generation nano-alloy electrode systems and quantum dots.

·         Synthesis and electrochemical interrogation of electroactive template-free poly(alkoxyanilines) hexagonal nanorod for application in highly efficient organic solar cell devices.

·         Fabrication of ion-transfer amperometric (ITA) DNA nanobiosensors based on polarisable liquid-liquid interfaces or supramolecular assemblies.

·         Methodology for the production of nanostructured polymeric nanotubes, nanorods, hydrogels and dendrimeric star polymers.

Abstract

Ampero-impedimetric responses of smart nanosensor systems

Emmanuel I. Iwuoha

SensorLab, Department of Chemistry, University of Western Cape, P. Bag X17, Bellville, Cape Town, 7535,South Africa. eiwuoha@uwc.ac.za. Tel: 021 959 3054

This presentation will focus on ‘smart’ materials (mainly conducting polymeric nanophase hydrogels1,2, dendritic star co-polymers3,4, binary and ternary nanoalloys5 and quantum dots6) produced by SensorLab for application in the development of nanosensor systems7 including therapeutic drug monitoring (TDM) nanobiosensors8, immunosensors for mycotoxins9 and DNA and DNA-aptamer genosensors10. For example, TDM biosensors can be used to provide real time information at point-of-care on the metabolic profile of a patient which is necessary for modulating therapy to the patient’s benefit. TDM nanobiosensors for antiretroviral (ARV), antituberculosis (ATB) and selective serotonin reuptake inhibitor (SSRI) drugs were prepared with genetically engineered heam-thiolate monooxygenase enzymes incorporated into poly(aniline-naphthalenesulphonate) nanotubes or polypyrrole-gold nanoparticles platforms. High resolution scanning and transmission electron microscopy, Hall Effect electronics and electrochemical impedance spectroscopy of the sensors and their amperometric response characteristics for SSRI and protease inhibitor ARV drugs will be presented. Also to be presented are studies in which aptamers, which are in vitro-selected functional oligonucleotides, have been employed in the design of novel aptasensor (i.e. DNA-aptamer genosensors) due to their inherent high selectivity and affinity compared to traditional biorecognition elements. For example, a novel aptamer biosensor for the determination of 17-β-estradiol (an estrogenic endocrine disrupting compound) was constructed with gold sensor chips functionalised with *SELEX-synthesised 76-mer biotinylated aptamer incorporated in a dendritic poly(propyleneimine)-co-poly(3,4-ethylenedioxythiopene) star copolymer. Other applications of smart materials to be presented are impedimetric immunosensors for mycotoxins, immunosensor for disease biomarkers (e.g. immunosensor for anti-tissue transglutaminase antibody, which is the biomarker for gluten intolerance autoimmune disorder also referred to as coeliac disease) and quantum dot biosensor systems for biomedical and environmental applications. (*SELEX: Systematic Evolution of Ligands by Exponential Enrichment).

References

  1. E. A. Songa, O. A. Arotiba, J.H.O. Owino, N. Jahed, P.G.L. Baker, E.I. Iwuoha. Electrochemical detection of glyphosate herbicide using horseradish peroxidase immobilized on sulfonated polymer matrix, Bioelectrochemistry (2009) 75: 117-123.
  2. A. Al-Ahmed, P. M. Ndangili, N. Jahed, P. G. L. Baker, E. I. Iwuoha. Polyester Sulphonic Acid Interstitial Nanocomposite Platform for Peroxide Biosensor. Sensors (2009) 9: 9965-9976.
  3. R. A. Olowu, P. M. Ndangili, A. A. Baleg, P.Baker, E. Iwuoha. Spectro-electrochemical dynamics of dendritic poly(propylene imine)-polythiophene star co-polymer aptameric 17-b-estradiol biosensor. Biosensors and Bioelectronics: (2010): under review.
  4. J. Martinovic, J. van Wyk, S. Mapolie, N. Jahed, P. Baker, E. Iwuoha Electrochemical and spectroscopic properties of dendritic cobalto-salicylaldiimine DNA biosensor, Electrochimica Acta (2010) 55: 4296-4302.
  5. S. N. Mailu, T. Waryo, R.A. Olowu, P. G. Baker, E. I. Iwuoha. Simultaneous amperometric detection of anthracene and phenanthrene on Ag-Au alloy nanoparticles/overoxidized-polypyrrole composite modified carbon electrode. Advaced Materials Letters (2010): in press.
  6. P.M. Ndangili, O.A. Arotiba, P.G.L. Baker, E.I. Iwuoha. A potential masking approach in the detection of dopamine on 3-mercaptopropionic acid capped ZnSe quantum dots modified gold electrode in the presence of interferences. Journal of Electroanalytical Chemistry (2010) 643: 77-81.
  7. E. I. Iwuoha, A. Al-Ahmed, M. Sekota, T. Waryo, P. Baker. Amperometric Sensors. In Encyclopedia of Supramolecular Chemistry (2007) Taylor & Francis, pp 1-18.
  8. Ignaszak, N. Hendricks, T.Waryo, E. Songa, N. Jahed, R. Ngece, A. Al-Ahmed, P. Baker, E.I. Iwuoha. Novel therapeutic biosensor for indinavir—A protease inhibitor antiretroviral drug. Journal of Pharmaceutical and Biomedical Analysis (2009) 49: 498–501.
  9. J. H. O. Owino, A. Ignaszak, A. Al-Ahmed, P.G. L. Baker, H. Alemu, J. C. Ngila, E. I. Iwuoha; Modelling of the impedimetric responses of an aflatoxin B1 immunosensor prepared on an electrosynthetic polyaniline platform. Analytical and Bioanalytical Chemistry (2007) 388: 1069-1074.
  10. R. A. Olowu, O. Arotiba, S.N. Mailu, T. Waryo, P. Baker , E. Iwuoha. Electrochemical aptasensor for endocrine disrupting 17β-estradiol based on poly(3,4-ethylenedioxylthiopene)-gold nanocomposite platform, Sensors (2010) 10: in press.