Rj. Williams et al., NEAR-INFRARED HEPTAMETHINE CYANINE DYES - A NEW TRACER FOR SOLID-PHASE IMMUNOASSAYS, Applied spectroscopy, 51(6), 1997, pp. 836-843
Near-infrared (near-IR) fluorescence has been used to develop a solid-
phase immunoassay that detects trace amounts of human immunoglobulin (
HuIgG). Various concentrations of HuIgG bound to a nitrocellulose surf
ace were determined from the fluorescence generated by near-IR labeled
goat anti-human antibody (GAHG) bound to the HuIgG, The GAHG was labe
led with a heptamethine cyanine fluorophore that has spectral properti
es in the near-IR region (above 780 nm), These fluorophores are versat
ile because they can be modified for several bioanalytical application
s, Fluorescence was detected with a near-IR fluorescence instrument pr
eviously developed in the laboratory, Two cyanine fluorophore labels w
ere evaluated for the ability to selectively bind to GAHG on a nitroce
llulose matrix with a minimal amount of background interference, After
the most appropriate near-IF fluorophore was selected, the labeling o
f GAHG was optimized under aqueous conditions, The most effective GAHG
-dye conjugates were used to develop an immunoassay to detect various
concentrations of HuIgG. The results are presented, here, Solutions of
HuIgG with concentrations as low as 10(-10) molar have been detected
with a minimum of interference.