A one-step homogeneous immunoassay for cancer biomarker detection using gold nanoparticle probes coupled with dynamic light scattering

    Authors

    X. Liu; Q. Dai; L. Austin; J. Coutts; G. Knowles; J. H. Zou; H. Chen;Q. Huo

    Comments

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    Abbreviated Journal Title

    J. Am. Chem. Soc.

    Keywords

    PROSTATE-SPECIFIC ANTIGEN; ORAL-CANCER; NANORODS; ASSAY; Chemistry, Multidisciplinary

    Abstract

    A one-step homogeneous immunoassay for the detection of a prostate cancer biomarker, free-PSA (prostate specific antigen), was developed using gold nanoparticle probes coupled with dynamic light scattering (DLS) measurements. A spherical gold nanoparticle with a core diameter around 37 nm and a gold nanorod with a dimension of 40 by 10 nm were first conjugated with two different primary anti-PSA antibodies and then used as optical probes for the immunoassay. In the presence of antigen f-PSA in solution, the nanoparticles and nanorods aggregate together into pairs and oligomers through the formation of a sandwich type antibody-antigen-antibody linkage. The relative ratio of nanoparticle-nanorod pairs and oligomers versus individual nanoparticles was quantitatively monitored by DLS measurement. A correlation can be established between this relative ratio and the amount of antigen in solution. The light scattering intensity of nanoparticles and nanoparticle oligomers is several orders of magnitude higher than proteins and other typical molecules, making it possible to detect nanoparticle probes in the low picomolar concentration range. f-PSA in the concentration range from 0.1 to 10 ng/mL was detected by this one-step and washing-free homogeneous immunoassay.

    Journal Title

    Journal of the American Chemical Society

    Volume

    130

    Issue/Number

    9

    Publication Date

    1-1-2008

    Document Type

    Article

    Language

    English

    First Page

    2780

    Last Page

    +

    WOS Identifier

    WOS:000253549800036

    ISSN

    0002-7863

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