Sensitive bioaffinity assays with individual microparticles and time-resolved fluorometry.
Future immunoassays and nucleic acid hybridization assays will be performed in miniaturized formats that utilize microchips or microparticles. This will require a sensitive detection technology that allows spatial resolution. By using fluorescent europium chelates and time-resolved microfluorometry, one can detect 11,000 europium molecules on individual microparticles. In a miniaturized noncompetitive immunoassay of prostate-specific antigen (PSA), we quantitatively detected 5 ng/L (0.05 amol per particle) of the analyte on an individual microparticle with excellent precision over the whole measurement range (CV <10%). Using a hybridization assay, we also could detect the deltaF508 mutation for cystic fibrosis on individual microparticles. Consequently, fluorescent lanthanide chelate labels and time-resolved microfluorometry qualify as the next generation of technology in this field.
Lövgren
T
T
Department of Biotechnology, University of Turku, Finland. timo.lovgren@utu.fi
Heinonen
P
P
Lehtinen
P
P
Hakala
H
H
Heinola
J
J
Harju
R
R
Takalo
H
H
Mukkala
V M
VM
Schmid
R
R
Lönnberg
H
H
Pettersson
K
K
Iitiä
A
A
D002614:Chelating Agents; D003550:Cystic Fibrosis / Q000235:genetics; D005063:Europium; D006801:Humans; D007118:Immunoassay / Q000592:standards*; D009154:Mutation; D017430:Prostate-Specific Antigen / Q000032:analysis; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence / Q000379:methods*; D013997:Time Factors
D002614:Chelating Agents; D005063:Europium; D017430:Prostate-Specific Antigen