A Europium Chelate for Quantitative Point-of-Care Immunoassays Using Direct Surface Measurement
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- 作者：Piia von Lode ; Jaana Rosenberg ; Kim Pettersson ; and Harri Takalo
- 刊名：Analytical Chemistry
- 出版年：2003
- 出版时间：July 1, 2003
- 年：2003
- 卷：75
- 期：13
- 页码：3193 - 3201
- 全文大小：301K
- 年卷期：v.75,no.13(July 1, 2003)
- ISSN：1520-6882
文摘
New labels and assay techniques are needed to improvethe sensitivity and quantitativeness of point-of-care immunotesting while sustaining the rapidity and ease of useof the assays. We synthesized a novel, intrinsically fluorescent nonadentate europium chelate with two chromophores and hydrophilic 
-galactose side groups. Thechelate is highly fluorescent, soluble in water, and provides effective shielding of Eu from water. The performance of the nonadentate chelate was compared with aheptadentate chelate in a dry reagent immunoassay forhuman chorionic gonadotropin (hCG). After 15-min incubation and washing, time-resolved fluorescence wasmeasured directly from a wet or dried well surface.Contrary to the heptadentate label, the effect of aqueousquenching on the nonadentate label was found to beinsignificant, with calculated analytical detection limits(background + 3 SD) of 0.9 and 0.7 IU/L hCG for wetand dry measurements, respectively, and a linear rangeup to 5000 IU/L. The CVs for the new label were <8% atthe cutoff of 25 IU/L and above in both whole blood andplasma. The novel nonadentate label facilitates shortturnaround times and simple instrumentation due to theabsence of all signal development steps, at the same timeretaining an excellent immunoassay performance.
-galactose side groups. Thechelate is highly fluorescent, soluble in water, and provides effective shielding of Eu from water. The performance of the nonadentate chelate was compared with aheptadentate chelate in a dry reagent immunoassay forhuman chorionic gonadotropin (hCG). After 15-min incubation and washing, time-resolved fluorescence wasmeasured directly from a wet or dried well surface.Contrary to the heptadentate label, the effect of aqueousquenching on the nonadentate label was found to beinsignificant, with calculated analytical detection limits(background + 3 SD) of 0.9 and 0.7 IU/L hCG for wetand dry measurements, respectively, and a linear rangeup to 5000 IU/L. The CVs for the new label were <8% atthe cutoff of 25 IU/L and above in both whole blood andplasma. The novel nonadentate label facilitates shortturnaround times and simple instrumentation due to theabsence of all signal development steps, at the same timeretaining an excellent immunoassay performance.