Project Summary (2005-2010)

Miniaturized biosensors can enable the toxicology projects to undertake their assays with high throughput and potentially with greater sensitivity. The Biosensor project aims to implement those bioassays that have been developed in the toxicology projects into usable biosensors. The project will have a fundamental aspect, and an applied aspect in which Dr. Kennedy intends to implement these assays. The fundamental aspects will investigate new nano scale materials for biolabeling, particularly with application to immunoassays. Long lifetime nano scale phosphors have been found to be particularly useful for labeling haptens, analytes, or antibodies in an immunoassay. The team will focus on the use of the lanthanide elements, in particular europium, and also other wavelengths that can be offered by the use of materials such as terbium oxide. The team will also investigate a novel format for carrying out immunoassays in a micro droplet. Samples that contain pico liters can be interrogated for very long times by using photobleaching labels, with the potential for approaching single molecule detection limits in assays. The more practical aspect of the project will be concerned with implementing existing assays in miniaturized biosensors on a chip. The researchers will also make use of micro fabrication techniques to make micro channels on a chip in which the team shall carry out the immunoassays. Dr. Kennedy will make use of indium tin oxide (ITO) films as waveguides and as electrodes to manipulate nanoparticles labels and antibodies in channels, and shall use evanescent detection of the particle labels within the channel, and use an electrostatic field to enhance binding to antibodies, and potentially to regenerate antibodies within the channel. The team will also attempt to improve the detection of DNA for sampling in soils. This will assist Project 1 in undertaking their measurements of toxin consuming bacteria within soils. The Biosensor project will implement an in vitro assay for dioxin for use in Project 5 and will work with Project 6 to implement a miniaturized, portable biosensor for markers of reproductive health.