Rapid, Miniaturized Sensors to Detect Environmenal Toxin

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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 bio assays that have been developed in the toxicology projects into usable biosensors. The project will have a fundamental aspect, and an applied aspect in which we intend to implement these assays. The fundamental aspects will investigate new nano scale materials for bio labeling, 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. We 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. We shall 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 with our 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. We shall make use of micro fabrication techniques to make micro channels on a chip in which we shall carry out the immunoassays. We shall make use of indium tin oxide (ITO) films as waveguides and as electrodes to manipulate nanoparticles labels and antibodies in channels. We 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. We shall 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 Dr. Denison's project and will work with Dr. Lasley's project to implement a miniaturized, portable biosensor for markers of reproductive health.