University of Guelph – Department of Chemistry

Abdelaziz Houmam

Research Interests

Surface modification and local manipulation

Our group is interested in the development of new approaches for the efficient organic and bioorganic modification of solid surfaces as well the local electrochemical modification of adsorbates on these surfaces. Our desire to attach molecules to surfaces and manipulate them is driven by the need for reliable immobilization techniques of organic molecules on solid surfaces as routes to surface passivation and incorporation of chemical/biochemical functionality at interfaces. The immobilization of organic and bioorganic molecules on solid surfaces is a central objective in the areas of nanotechnology and microarray technologies. Development of sensors and molecular electronic devices are directly related to advances in immobilization techniques and methodologies for molecular manipulation and control of surface adsorbates.

We are interested in conducting, semi-conducting and non-conducting surfaces as substrates for the modification. The goal is to develop techniques, which will have the advantages of producing more dense and uniform films in addition to being reproducible. We are presently working on the following projects:

1) The organic modification of Au surfaces

2) The organic modification of Si surfaces

3) The local manipulation of organic adsorbates on solid surfaces

Electron transfer in organic and bioorganic molecules

Understanding of inter and intramolecular electron transfer and factors controlling both processes in chemically and biologically important systems is not only important from a fundamental point of view but also for applications in areas such as molecular electronic devices, photo-imaging and amperometric sensors, whose development is directly related to advances in the understanding of the electron transfer processes. For example, a very promising way of constructing amperometric and potentiometric DNA-based biosensors is the immobilization of DNA containing an electroactive centre on a conducting surface, i.e. an electrochemical transducer. The interaction between the immobilized DNA and the analyte (a molecule of interest whose interaction with the immobilized DNA is known) induces changes in the electrochemical response of the transducer (change in the current or potential or both) and this change is used for the detection of this analyte. In such a device the flow of electrons between the conducting surface and the electroactive centre through the DNA is the key factor in the detection process. A good understanding of the electron transfer in DNA is therefore necessary. DNA is only one example for this and other systems are as relevant. This area of research is related to the previous one and is in our case a necessary step to the development of new electrochemical techniques for surface modification through a good understanding of the dynamics of the electron transfer reactions to a series of organic and bioorganic compounds.