Catalytic DNA Biosensor for Toxic Metal Ions

DESCRIPTION (provided by applicant): Cost-effective catalytic DNA biosensors for heavy metal ions such as lead(II), uranium(VI), mercury(II), and cadmium(II) will be developed. They will be tested for on-site, real-time detection and quantification with mi nimal rates of false positive or false negative results. Exposure to these metal ions can cause severe adverse health effects, such as damages to brain, kidneys, and cancers, to human beings, especially children. Current technologies for metal detection em ploy either expensive or sophisticated instruments or simple sensors, many of which have high rates of false positive or false negative results. Therefore there is an urgent need of reliable portable heavy metal sensors for government inspectors, environme ntal monitors, household users, clinicians in rural or remote areas, and first-responders in the war against terrorism, where on-site, real-time, and cost-effective detection and quantification are critical and the market for heavy metal detection is estim ated to be gt 650 million. The project is based on several innovations in the PI's group at the University of Illinois that takes advantage of state-of-the-art tools in catalytic DNA biology, catalytic molecular beacons biotechnology and nanoparticle nanot echnology. Catalytic DNA molecules specific for heavy metal ions will be obtained through in vitro selection, and converted to fluorescent (for quantitative measurement) and colorimetric (for qualitative and semi-quantitative measurement) sensors by combin ing the DNA with fluorophore/quencher pairs and gold nanoparticles, respectively. The feasibility of transforming the innovations into commercial success at the DzymeTech has been established in the NIH STTR Phase I project (1R41ES014125-01), in which cata lytic DNA sensors for lead(II) and uranium(VI) have been obtained that have high sensitivity (e.g., ~ 11 ppt) and selectivity (e.g., gt 1 million fold). This Phase II application addresses critical issues of transferring the sensor design into prototypes o f sensor kits for markets. The customer requirements will be determined and prototype components and protocols will be developed. They include: Obtain all four fluorescent and colorimetric sensors for Pb(II), U(VI), Cd(II), and Hg(II). Characterize the se nsors by determining the detection limit and selectivity of each sensor. Design and characterize prototype sensor kits for each metal ion. Including sensor components, storage condition and test protocol optimization, high/low temperature stability tests and reproducibility tests with sensors from multiple-batches. Test field samples to study interference and matrix effects. Real field samples, including soil and water samples will be collected and tested. Sensor performance with real samples will be used to evaluate the commercialization values of the sensor kits. PUBLIC HEALTH RELEVANCE: Highly sensitive and selective catalytic DNA sensors for lead(II), uranium(VI), cadmium(II), and mercury(II) will be developed for cost-effective on-site and real -time detection and quantification. Heavy metal ions are widely present in the environment, causing significant health problems such as damages to brain, kidney, and neural system to human beings, especially children. Convenient portable sensors developed in this project will enable government inspectors, environmental monitors, household users, clinicians and first-responders make informed decision about remediation and monitoring strategy and thus improve human health and quality of life.