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Nanoparticles, Biosensors

Last updated on 01/27/2009

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Sensitive, effective means of environmental effects monitoring are vital to ecosystem protection, including the identification of environmental hazards and the effects of toxic substances and nutrients. Nanotechnology-based platforms for the high-throughput, multiplexed detection of proteins and DNA promise to bring substantial advances in environmental, food and clinical diagnostics. In our newly developed technology, current chip-based microarrays are replaced with a nanoparticles-based technology by shifting the immobilizing probe DNA from the chip surface to a nanoparticle surface, and performing hybridization in solution with target DNA. Magnetic/luminescent (Fe3O4/Eu:Gd2O3) core-shell nanoparticles were designed to offer multi-functional advantage: the magnetic property of NPs provides an efficient separation of NP-DNA hybrids from the solution, which speeds up the assay time; the stable and long-lasting fluorescence from the lanthanide shell serves as an internal calibration for organic dye labels. This project is collaboration with Prof. Kennedy and his group in the Mechanical and Aeronautical Engineering Department here at UCD and is funded by NIEHS Superfund.

We demonstrated the advantage of nanotechnology for detection of MTBE-degrading bacteria and antibiotic resistance genes and its potential for implementation in portable biosensors to support field measurements (work in progress). We are collaborating with Dr. Robert Weiss (Dept. Internal Medicine, UCD) on application of our newly developed nanotechnology for detection of genetic mutations and towards improved diagnosis of genetic diseases (fig.1). The technology has also potential for detection of cancer biomarkers such as p53 mutations. Our assays are attractive from the viewpoint of its rapid availability, simple methodology, and cost reduction for clinical use to detect mutations.


Fig. 1. Hybridization in solution result for PKD SNPs detection assay using PCR-amplified genomic DNA (feline exon29, 550 bp product) (a).; TEM image of Eu:Gd2O3(b); schematic diagram of multiplex assay for detection of MTBE degradation genes (c).

In a different project we are integrating the state of the art magnetic tunnel junction sensor with magnetic particles as detection labels for the DNA microarrays. In collaboration with Dave Horsley and his group, we are developing the fundamental technology for a low-cost disk-drive based bioassay system for the detection of magnetically-labeled DNA microarrays.


Son, A., D. Dosev, M. Nichkova, Z. Ma, K. Scow, I. M. Kennedy, and K.R. Hristova. 2007. Quantitative DNA hybridization in solution using magnetic/luminescent core-shell nanoparticles. Anal. Biochemistry 370: 186-194.

Son, A., A. Dhirapong, D. Dosev, I.M.Kennedy, R.H.Weiss, and K.R. Hristova. 2008. Rapid and quantitative DNA analysis of genetic mutations for polycystic kidney disease (PKD) using magnetic/luminescent nanoparticles. Analytical and Bioanalytical Chemistry. 390:1829-1835.

Son, A, M. Nichkova, D. Dosev, I. Kennedy, and K. R. Hristova. 2008. Luminescent lanthanide nanoparticle labels in DNA-based microarray approach for quantification of MTBE degrading bacteria. J. Nanoscience and Nanotechnology 8 (5):2463-2467.

Son, A, K.R. Hristova, D. Dosev, and I. Kennedy. 2008. Quantitative detection of antibiotic resistance genes using magnetic/ luminescent core-shell nanoparticles. In: Nanoscale Imaging, Sensing, and Actuation for Biomedical Applications V. edited by Alexander N. Cartwright, Dan V. Nicolau. Proceedings of SPIE Vol. 6865, 68650P.

Chan, M.-L., G. M. Jaramillo, A. Son, K.R. Hristova and D. A. Horsley. 2008. Scanning Tunneling Magnetoresistance Microscopy for the Detection of Magnetically Labeled DNA Microarrays. Appl. Phys. Lett. (under review).