A. Perrin et al., THYROID-STIMULATING HORMONE ASSAYS BASED ON THE DETECTION OF GOLD CONJUGATES BY SCANNING FORCE MICROSCOPY, Analytical biochemistry, 256(2), 1998, pp. 200-206
Citations number
26
Categorie Soggetti
Biology,"Biochemical Research Methods","Chemistry Analytical
Low bulk concentrations of thyroid stimulating hormone (TSH) were dete
cted by scanning force microscopy (SFM) using gold-labeled conjugates.
Anti-TSH antibodies were covalently bound onto amino-modified silicon
oxide wafers, Surface modification was examined by contact-angle meas
urements, ellipsometry, PL-ray photoelectron spectroscopy, and SFM, An
tibodies were found to form a monolayer of prone molecules with an ave
rage surface density of 5000 IgG/mu m(2). TSH molecules were then allo
wed to bind to immobilized antibodies, The immunological reaction was
quantified by SFM using gold-labeled species. Two scanned force micros
copic immunoassays (SFMIA) were compared first, a competitive test whi
ch used gold-labeled TSH molecules mixed with free TSH antigens was pe
rformed, Afterward, IL sandwich assay was carried out, using gold-labe
led anti-TSH antibodies. This latter method was found to be far more s
ensitive than competitive SFMIA. Gold conjugates were also found to be
of great use to quantify antigens in large volumes by a sandwich test
: a sensitivity threshold as low as 0.015 ng of TSH/ml (0.075 mu UI/ml
or 6 x 10(-13) M) was estimated. (C) 1998 Academic Press.