Abstract
Background: We describe a direct-detection immunoassay that uses high-speed optical interferometry on a biological compact disc (BioCD). Methods: We fabricated phase-contrast BioCDs from 100-mm diameter 1.1-mm thick borosilicate glass disks coated with a 10-layer dielectric stack of Ta2O 5/SiO2 that serves as a mirror with a center wavelength at 635 nm. The final layer is a λ/4 layer of SiO2 onto which protein patterns are immobilized through several different chemical approaches. Protein on the disc is scanned by a focused laser spot as the disc spins. Interaction of the light with the protein provides both a phase-modulated signal and a local reference that are combined interferometrically to convert phase into intensity. A periodic pattern of protein on the spinning disc produces an intensity modulation as a function of time that is proportional to the surface-bound mass. The binding of antigen or antibodies is detected directly, without labels, by a change in the interferometric intensity. The technique is demonstrated with a reverse assay of immobilized rabbit and mouse IgG antigen incubated against anti-IgG antibody in a casein buffer. Results: The signal increased with increased concentration of analyte. The current embodiment detected a concentration of 100 ng/L when averaged over ∼3000 100-micron-diameter protein spots. Conclusions: High-speed interferometric detection of label-free protein assays on a rapidly spinning BioCD is a high-sensitivity approach that is amenable to scaling up to many analytes.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 2135-2140 |
| Number of pages | 6 |
| Journal | Clinical Chemistry |
| Volume | 52 |
| Issue number | 11 |
| DOIs | |
| State | Published - Nov 2006 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Clinical Biochemistry
Cite this
High-speed interferometric detection of label-free immunoassays on the biological compact disc. / Zhao, Ming; Nolte, David; Cho, Wonryeon; Regnier, Fred; Varma, Manoj; Lawrence, Greg; Pasqua, John.
In: Clinical Chemistry, Vol. 52, No. 11, 11.2006, p. 2135-2140.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - High-speed interferometric detection of label-free immunoassays on the biological compact disc
AU - Zhao, Ming
AU - Nolte, David
AU - Cho, Wonryeon
AU - Regnier, Fred
AU - Varma, Manoj
AU - Lawrence, Greg
AU - Pasqua, John
PY - 2006/11
Y1 - 2006/11
N2 - Background: We describe a direct-detection immunoassay that uses high-speed optical interferometry on a biological compact disc (BioCD). Methods: We fabricated phase-contrast BioCDs from 100-mm diameter 1.1-mm thick borosilicate glass disks coated with a 10-layer dielectric stack of Ta2O 5/SiO2 that serves as a mirror with a center wavelength at 635 nm. The final layer is a λ/4 layer of SiO2 onto which protein patterns are immobilized through several different chemical approaches. Protein on the disc is scanned by a focused laser spot as the disc spins. Interaction of the light with the protein provides both a phase-modulated signal and a local reference that are combined interferometrically to convert phase into intensity. A periodic pattern of protein on the spinning disc produces an intensity modulation as a function of time that is proportional to the surface-bound mass. The binding of antigen or antibodies is detected directly, without labels, by a change in the interferometric intensity. The technique is demonstrated with a reverse assay of immobilized rabbit and mouse IgG antigen incubated against anti-IgG antibody in a casein buffer. Results: The signal increased with increased concentration of analyte. The current embodiment detected a concentration of 100 ng/L when averaged over ∼3000 100-micron-diameter protein spots. Conclusions: High-speed interferometric detection of label-free protein assays on a rapidly spinning BioCD is a high-sensitivity approach that is amenable to scaling up to many analytes.
AB - Background: We describe a direct-detection immunoassay that uses high-speed optical interferometry on a biological compact disc (BioCD). Methods: We fabricated phase-contrast BioCDs from 100-mm diameter 1.1-mm thick borosilicate glass disks coated with a 10-layer dielectric stack of Ta2O 5/SiO2 that serves as a mirror with a center wavelength at 635 nm. The final layer is a λ/4 layer of SiO2 onto which protein patterns are immobilized through several different chemical approaches. Protein on the disc is scanned by a focused laser spot as the disc spins. Interaction of the light with the protein provides both a phase-modulated signal and a local reference that are combined interferometrically to convert phase into intensity. A periodic pattern of protein on the spinning disc produces an intensity modulation as a function of time that is proportional to the surface-bound mass. The binding of antigen or antibodies is detected directly, without labels, by a change in the interferometric intensity. The technique is demonstrated with a reverse assay of immobilized rabbit and mouse IgG antigen incubated against anti-IgG antibody in a casein buffer. Results: The signal increased with increased concentration of analyte. The current embodiment detected a concentration of 100 ng/L when averaged over ∼3000 100-micron-diameter protein spots. Conclusions: High-speed interferometric detection of label-free protein assays on a rapidly spinning BioCD is a high-sensitivity approach that is amenable to scaling up to many analytes.
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U2 - 10.1373/clinchem.2006.072793
DO - 10.1373/clinchem.2006.072793
M3 - Article
VL - 52
SP - 2135
EP - 2140
JO - Clinical Chemistry
JF - Clinical Chemistry
SN - 0009-9147
IS - 11
ER -