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Fast and Sensitive Interferon-γ Assay Using Supercritical Angle Fluorescence.

Winterflood CM, Ruckstuhl T, Seeger S - Biosensors (Basel) (2013)

Bottom Line: We present an immunoassay for Interferon-γ (IFN-γ) with a limit of detection of 1.9 pM (30 pg/mL) and a linear concentration range spanning three orders of magnitude.The solid-phase sandwich assay is performed on a new measurement system comprising single-use test tubes and a compact fluorescence reader.The polymer tubes contain an optical configuration for the detection of supercritical angle fluorescence, allowing for highly sensitive real-time binding measurements.

View Article: PubMed Central - PubMed

Affiliation: Physikalisch-Chemisches Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland; E-Mails: c.winterflood@pci.uzh.ch (C.M.W.); t.ruckstuhl@pci.uzh.ch (T.R.).

ABSTRACT
We present an immunoassay for Interferon-γ (IFN-γ) with a limit of detection of 1.9 pM (30 pg/mL) and a linear concentration range spanning three orders of magnitude. The developed one-step assay takes only 12 min and can replace the time-consuming and labor-intensive enzyme-linked immunosorbent assay (ELISA). The solid-phase sandwich assay is performed on a new measurement system comprising single-use test tubes and a compact fluorescence reader. The polymer tubes contain an optical configuration for the detection of supercritical angle fluorescence, allowing for highly sensitive real-time binding measurements.

No MeSH data available.


(a) Photograph and (b) schematic of the test tube. (c) Schematic of the fluorescence reader. Adapted from [14].
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biosensors-03-00108-f002: (a) Photograph and (b) schematic of the test tube. (c) Schematic of the fluorescence reader. Adapted from [14].

Mentions: The SAF immunodiagnostic system, shown in Figure 2, comprises mass producible polymer test tubes and a compact fluorescence reader. The tube consists of two polymer components and a standard O-ring. The lower part containing the optics was fabricated by injection molding of the cyclo-olefin polymer Zeonex™ (Zeon Chemicals, Tokyo, Japan). An aspheric surface at its bottom side focuses collimated excitation light to a light disk of 50 μm diameter at the upper surface of the substrate. The excited fluorescence bound at the substrate is collected at angles between 63° and 78° by a parabolic shell surface environed by air. The collected angles lie above the critical angle between the aqueous sample and the substrate of θc = 61°. The fluorescence collection efficiency of the tube optics is with ~27%, comparable to the collection efficiency of the microscope objectives of high numerical aperture. The cylindrical base of the substrate is the connector between the tube and fluorescence reader. The optical interfaces (asphere, bottom flat) are concealed inside this hollow cylinder to prevent damage and contamination. The substrates were fabricated with high optical accuracy by Syntec Optics (Pavillion, NY, USA). After the immobilization of capture antibodies on the upper flat surface, the substrate was assembled, with the upper part of the tube injection molded from polycarbonate and black additive. A snug fit establishes a strong junction between the tube parts. The tube has the same diameter (10.7 mm) as its well-known counterpart from Eppendorf and is therefore compatible with common laboratory equipment (shakers, centrifuges, thermocyclers, etc.).


Fast and Sensitive Interferon-γ Assay Using Supercritical Angle Fluorescence.

Winterflood CM, Ruckstuhl T, Seeger S - Biosensors (Basel) (2013)

(a) Photograph and (b) schematic of the test tube. (c) Schematic of the fluorescence reader. Adapted from [14].
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4263590&req=5

biosensors-03-00108-f002: (a) Photograph and (b) schematic of the test tube. (c) Schematic of the fluorescence reader. Adapted from [14].
Mentions: The SAF immunodiagnostic system, shown in Figure 2, comprises mass producible polymer test tubes and a compact fluorescence reader. The tube consists of two polymer components and a standard O-ring. The lower part containing the optics was fabricated by injection molding of the cyclo-olefin polymer Zeonex™ (Zeon Chemicals, Tokyo, Japan). An aspheric surface at its bottom side focuses collimated excitation light to a light disk of 50 μm diameter at the upper surface of the substrate. The excited fluorescence bound at the substrate is collected at angles between 63° and 78° by a parabolic shell surface environed by air. The collected angles lie above the critical angle between the aqueous sample and the substrate of θc = 61°. The fluorescence collection efficiency of the tube optics is with ~27%, comparable to the collection efficiency of the microscope objectives of high numerical aperture. The cylindrical base of the substrate is the connector between the tube and fluorescence reader. The optical interfaces (asphere, bottom flat) are concealed inside this hollow cylinder to prevent damage and contamination. The substrates were fabricated with high optical accuracy by Syntec Optics (Pavillion, NY, USA). After the immobilization of capture antibodies on the upper flat surface, the substrate was assembled, with the upper part of the tube injection molded from polycarbonate and black additive. A snug fit establishes a strong junction between the tube parts. The tube has the same diameter (10.7 mm) as its well-known counterpart from Eppendorf and is therefore compatible with common laboratory equipment (shakers, centrifuges, thermocyclers, etc.).

Bottom Line: We present an immunoassay for Interferon-γ (IFN-γ) with a limit of detection of 1.9 pM (30 pg/mL) and a linear concentration range spanning three orders of magnitude.The solid-phase sandwich assay is performed on a new measurement system comprising single-use test tubes and a compact fluorescence reader.The polymer tubes contain an optical configuration for the detection of supercritical angle fluorescence, allowing for highly sensitive real-time binding measurements.

View Article: PubMed Central - PubMed

Affiliation: Physikalisch-Chemisches Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland; E-Mails: c.winterflood@pci.uzh.ch (C.M.W.); t.ruckstuhl@pci.uzh.ch (T.R.).

ABSTRACT
We present an immunoassay for Interferon-γ (IFN-γ) with a limit of detection of 1.9 pM (30 pg/mL) and a linear concentration range spanning three orders of magnitude. The developed one-step assay takes only 12 min and can replace the time-consuming and labor-intensive enzyme-linked immunosorbent assay (ELISA). The solid-phase sandwich assay is performed on a new measurement system comprising single-use test tubes and a compact fluorescence reader. The polymer tubes contain an optical configuration for the detection of supercritical angle fluorescence, allowing for highly sensitive real-time binding measurements.

No MeSH data available.