School of Chemical Sciences


Gene Biosensors

Contact Researchers: Assoc. Prof. Jadranka Travas-Sejdic, Assoc. Prof. Christian Soeller

Analysis of gene expression using gene sensors is rapidly becoming the most powerful way to accurately diagnose disease, discover mutations and monitor biotechnology processes in our post genomic era. Scientists at the Center have developed a range of novel DNA sensor technologies based on conducting polymers, photoluminescent polymers and inorganic nanocrystals (Quantum Dots) for simple, rapid and sensitive gene detection with intrinsic electrical and/or optical readouts.

Functionalized Pyrrole and Thiophene


We have developed a range of functionalized polypyrroles that provide specific one-step detection of DNA fragments. The chemical nature of the ‘linker’ chain between the polymer backbone and the grafted DNA probe sequence has a tremendeous effect on the sensor properties (Dr Hui Peng). Polythiophene derivatives are being investigated for use in the construction of DNA sensors with the output monitored using electrochemical impedance spectroscopy and UV-Vis electrospectrophotometry (John Spires - PhD).

images to show the process of hybridlzation

Water-soluble quantum dots


Quantum dots (QDs) have attracted tremendous interest over the past decade due to their narrow and intensive emission spectra, high chemical and photobleaching stability, and surface functionality, which give them great potential in applications such as biological sensing. An aqueous, photo-assisted synthesis of CdTe QDs has been developed which offers an alternative approach to the most widely used organometallic synthesis of QDs (Dr Hui Peng). A surface-immobilized sensor, based on mixed self-assembled monolayers (SAMs), including quantum dot (QD) labeled and label free sensor designs are being investigated with the aim to develop a one-step sensor, offering direct and specific detection of target DNA (Tanja Kjällman - PhD).

Conducting polymer nanowires


Individually addressable conducting polymer nanowires will be synthesized or grown across the small gaps between micro fabricated electrodes through electropolymerisation and monitoring using AFM. Ultimately the utility of functionalized nanowires as biosensors will be investigated (Bhuvaneswari Kannan - PhD)

Recent publications


  • J.B. Spires, H. Peng, D.E. Williams, C. Soeller and J. Travas-Sejdic, "Solvent-induced microstructure chnages and consequences for electrochemical activity of redox-active conducting polymers", Electrochimica Acta 55 (2010) 3061-3067.
  • T.H.M. Kjällman, H. Peng, C. Soeller and J. Travas-Sejdic, "A CdTe nanoparticle-modified hairpin probe for direct and sensitive electrochemical detection of DNA", Analyst 135 (2010) 488-494.
  • H. Peng, L. Zhang, C. Soeller and J. Travas-Sejdic, "Conducting polymers for electrochemical DNA sensing", Biomaterials 30 (2009) 2132-2148.
  • H. Peng, L. Zhang, P.A. Kilmartin, Z. Zujovic, C. Soeller and J. Travas-Sejdic, "Quantum dots and nanostructured conducting polymers for biosensing applications", International Journal of Nanotechnology 6 (2009) 418-430.
  • T.H.M. Kjällman, H. Peng, C. Soeller and J. Travas-Sejdic, "Effect of Probe Density and Hybridization Temperature on the Response of an Electrochemical Hairpin-DNA Sensor", Analytical Chemistry 80 (2008) 9460-9466.
  • J.B. Spires, H. Peng, D.E. Williams, B.E. Wright, C. Soeller and J. Travas-Sejdic, "The effect of the oxidation state of a terthiophene-conducting polymer and of the presence of a redox probe on its gene-sensing properties", Biosensors and Bioelectronics 24 (2008) 928-933.
  • T. Kjällman, H. Peng, C. Soeller and J. Travas-Sejdic, "Quenching of an indocarbocyanine dye and functionalized CdSe/ZnS quantum dots by gold surfaces", Current Applied Physics 8 (2008) 308-311, 2008.
  • J. Travas-Sejdic and C. Soeller, "Sensing Genes Using Conducting Polymers and Nanoparticles" in Handbook of Organic Electronics and Photonics (Editor H.S. Nalwa, American Scientific Publishers), ISBN: 1-58883-095-0, 2007.
  • H. Peng, L.J. Zhang, T.H.M. Kjallman, C. Soeller and J. Travas-Sejdic, "DNA Hybridization Detection with Blue Luminescent Quantum Dots and Dye-Labeled Single-Stranded DNA", Journal of the American Chemical Society 129 (2007) 3048.
  • H. Peng, L. Zhang, J. Spires, C. Soeller and J. Travas-Sejdic, "Synthesis of functionalized polythiophene as an active substrate for label-free electrochemcial genosensor," Polymer 48 (2007) 3413-3419.
  • H. Peng, C. Soeller, N.A. Vigar, V. Caprio and J. Travas-Sejdic, "Label-free detection of DNA hybridization based on a novel functionalized conducting polymer," Biosensors and Bioelectronics 22 (2007) 1868-1873.
  • H. Peng, C. Soeller and J. Travas-Sejdic, "Novel Conducting Polymers for DNA Sensing", Macromolecules 40 (2007) 909-914.
  • H. Peng, L. Zhang, C. Soeller and J. Travas-Sejdic, "Preparation of water-soluble CdTe/CdS core/shell quantum dots with enhanced photostability", Journal of Luminescence 127 (2007) 721-726.