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Your Environment. Your Health.

Final Progress Reports: University of California-Davis: Development of Rapid, Miniaturized Biosensors

Superfund Research Program

Development of Rapid, Miniaturized Biosensors

Project Leader: Ian M. Kennedy
Grant Number: P42ES004699
Funding Period: 2000-2015
View this project in the NIH Research Portfolio Online Reporting Tools (RePORT)

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Final Progress Reports

Year:   2014  2009  2004 

During the past year, the team’s efforts were focused on optimization of the newly developed fluorescent lanthanide oxide nanoparticles as well as on the development and optimization of new application schemes for bio-detection. The effect of the particle size on particles’ physical properties was studied and correlated to the synthesis process. This allows for better control of material properties, which are important for applications. In parallel, the effect of the particle size on the kinetics of immunoassays in a microchannel was studied and optimized. The results are important for the optimization of the speed and the sensitivity of the assay using the novel labels. New microchannels made of polymers were designed and fabricated. This reduces significantly the device fabrication cost and time and makes possible the mass fabrication of disposable microchannels for immunoassays. It also allows for more flexibility in the channel design. A microchannel technique (micro-electric field flow fractionation μ-EFFF) for size separation and colloidal characterization of nanoparticles was developed and optimized for polystyrene nanoparticles. The information about particles colloidal properties obtained by this technique is important for further application of the nanoparticles. The researchers have developed two new methods for the surface coating and functionalization of the nanoparticles and they were added to their provisional patent application. The new methods were optimized for coating with a variety of widely used proteins including antibodies of specific interest for environmental detection. Each one of the newly developed methods allows for precise control of binding sites per particle, which is of key importance for the optimization of the immunoassay sensitivity. In addition, novel techniques with improved sensitivity and precision were developed for the quantification of the surface functional groups and binding sites. Using functionalized fluorescent nanoparticles, the researchers have developed novel biosensing scheme based on protein microcontact printing. Antibodies of interest were printed using the microcontact printing technique. Then the corresponding antigen labeled with fluorescent nanoparticles was recognized and specifically bound on the printed surface. The results were observed using fluorescent microscopy and atomic force microscopy (AFM). This detection scheme was optimized for avidin-biotin as a model system. Positive results were obtained for antibody-antibody recognition and also for antibody against small molecule (phenoxybenzoic acid PBA). The viability of the scheme for different types of proteins and small molecules makes it promising for a large variety of applications including environmental studies. Organic dyes were found to bleach under fluorescent microscope. Hence, the lack of photobleaching of the fluorescent nanoparticles is a crucial advantage for this type of application.

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