Antibody-nanoparticle conjugates to enhance the sensitivity of ELISA-based detection methods

Author(s)Billingsley, Margaret M.
Author(s)Riley, Rachel S.
Author(s)Day, Emily S.
Ordered AuthorMargaret M. Billingsley, Rachel S. Riley, Emily S. Day
UD AuthorBillingsley, Margaret M.en_US
UD AuthorRiley, Rachel S.en_US
UD AuthorDay, Emily S.en_US
Date Accessioned2017-09-12T17:51:02Z
Date Available2017-09-12T17:51:02Z
Copyright DateCopyright © 2017 Billingsley et al.en_US
Publication Date2017-05-11
DescriptionPublisher's PDFen_US
AbstractAccurate antigen detection is imperative for clinicians to diagnose disease, assess treatment success, and predict patient prognosis. The most common technique used for the detection of disease-associated biomarkers is the enzyme linked immunosorbent assay (ELISA). In an ELISA, primary antibodies are incubated with biological samples containing the biomarker of interest. Then, detectible secondary antibodies conjugated with horseradish peroxidase (HRP) bind the primary antibodies. Upon addition of a color-changing substrate, the samples provide a colorimetric signal that directly correlates to the targeted biomarker concentration. While ELISAs are effective for analyzing samples with high biomarker content, they lack the sensitivity required to analyze samples with low antigen levels. We hypothesized that the sensitivity of ELISAs could be enhanced by replacing freely delivered primary antibodies with antibody-nanoparticle conjugates that provide excess binding sites for detectible secondary antibodies, ultimately leading to increased signal. Here, we investigated the use of nanoshells (NS) decorated with antibodies specific to epidermal growth factor receptor (EGFR) as a model system (EGFR-NS). We incubated one healthy and two breast cancer cell lines, each expressing different levels of EGFR, with EGFR-NS, untargeted NS, or unconjugated EGFR antibodies, as well as detectable secondary antibodies. We found that EGFR-NS consistently increased signal intensity relative to unconjugated EGFR antibodies, with a substantial 13-fold enhancement from cells expressing high levels of EGFR. Additionally, 40x more unconjugated antibodies were required to detect EGFR compared to those conjugated to NS. Our results demonstrate that antibody-nanoparticle conjugates lower the detection limit of traditional ELISAs and support further investigation of this strategy with other antibodies and nanoparticles. Owing to their enhanced sensitivity, we anticipate that nanoparticle-modified ELISAs can be used to detect low levels of biomarkers found in various diseases, such as cancers, tuberculosis, and rheumatoid arthritis, and may ultimately enable earlier diagnosis, better prognostication, and improved treatment monitoringen_US
DepartmentUniversity of Delaware. Department of Biomedical Engineering.en_US
DepartmentUniversity of Delaware. Department of Materials Science and Engineering.en_US
CitationBillingsley MM, Riley RS, Day ES (2017) Antibody-nanoparticle conjugates to enhance the sensitivity of ELISA-based detection methods. PLoS ONE 12(5): e0177592. 10.1371/journal.pone.0177592en_US
PublisherPublic Library of Science (PLOS)en_US
dc.rightsArticle is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.en_US
dc.rightsCC-BY 4.0en_US
dc.sourcePLOS Oneen_US
TitleAntibody-nanoparticle conjugates to enhance the sensitivity of ELISA-based detection methodsen_US
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