About This Project

Ask the Scientists

What is the context of this research?

Metal nanoparticles due to their small size are becoming incorporated into many aspects of our lives. Gold nanoparticles can be used in diagnostic devices to detect diseases such as cancer. Silver nanoparticles can be incorporated into fabrics for their antimicrobial properties, while titanium dioxide is included in sunscreens due to their UV absorption.

The conventional methods to produce these nanoparticles however, use potentially hazardous compounds and/or extreme synthesis conditions (such as high temperature or pressure), which raises the cost of their synthesis and concerns about their environmental impact.

Other methods can be complex and lead to unrepeatable results. A cheaper and greener method is needed to improve the viability of this technology.

What is the significance of this project?

In the last 14 years many micro-organisms have been demonstrated to produce metal nanoparticles as a defense mechanism against the toxic actions of the metal ions in solution.

These methods do not require the addition of potential harmful compounds, as the microbe produces both reducing agent and capping ligand. Further, due to the high specificity of the interaction between the biomolcules and the inorganic template, the reaction can take place at room temperature and the procedure is easy to follow.

Although this method addresses the problems of the conventional methods, the nanoparticles produced are not of a uniform size. As the properties of the nanoparticle are dependent on their size, this is holding back the biological methods from academic interest to real world applications.

What are the goals of the project?

The goal of this project is to produce uniform silver nanoparticles using electrochemically stimulated Shewanella sp biofilms. Our research will examine the effect of the working electrode material, the species of Shewanella, growth conditions and the applied electrochemical potential. Further we will optimize these parameters to improve silver nanoparticle uniformity.