Activated phosphonated trifunctional chelates for highly sensitive lanthanide-based FRET immunoassays applied to total prostate specific antigen detection
作者:Katia Nchimi-Nono、K. David Wegner、Stina Lindén、Alexandre Lecointre、Laurence Ehret-Sabatier、Shakir Shakir、Niko Hildebrandt、Loïc J. Charbonnière
DOI:10.1039/c3ob40898a
日期:——
The first example of an activated phosphonated trifunctional chelate (TFC) is presented, which combines a non-macrocyclic coordination site for lanthanide coordination based on two aminobis-methylphosphonate coordinating arms, a central bispyrazolylpyridyl antenna and an N-hydroxysuccinimide ester in para position of the central pyridine as an activated function for the labeling of biomaterial. The synthesis of the TFC is presented together with photo-physical studies of the related Tb and Eu complexes. Excited state lifetime measurements in H2O and D2O confirmed an excellent shielding of the cation from water molecules with a hydration number of zero. The Tb complex provides a high photoluminescence (PL) quantum yield of 24% in aqueous solutions (0.01 M Tris–HCl, pH 7.4) and a very long luminescence lifetime of 2.6 ms. The activated ligand was conjugated to different biological compounds such as streptavidin, and a monoclonal antibody against total prostate specific antigen (TPSA). In combination with AlexaFluor647 (AF647) and crosslinked allophycocyanin (XL665) antibody (ABs) conjugates, homogeneous time-resolved Fluorescence Resonance Energy Transfer (FRET) immunoassays of TPSA were performed in serum samples. The Tb donor–dye acceptor FRET pairs provided large Förster distances of 5.3 nm (AF647) and 7.1 nm (XL665). A detailed time-resolved FRET analysis of Tb donor and dye acceptor PL decays revealed average donor–acceptor distances of 4.2 nm (AF647) and 6.3 nm (XL665) within the sandwich immunocomplex and FRET efficiencies of 0.79 and 0.68, respectively. Very low detection limits of 1.4 ng mL−1 (43 pM) and 2.4 ng mL−1 (74 pM) TPSA were determined using a KRYPTOR fluorescence immunoanalyzer. These results demonstrate the applicability of our novel Tb-bioconjugates for highly sensitive clinical diagnostics.
首次报道了一种活化的膦酸化三功能螯合剂(TFC)的实例,该螯合剂结合了基于两个氨基双甲基膦酸配体臂的非大环配位位点用于镧系元素配位,以及一个中央的双吡唑基吡啶天线和位于中央吡啶对位的N-羟基琥珀酰亚胺酯作为标记生物材料的活化功能。介绍了TFC的合成以及相关Tb和Eu配合物的光物理研究。在H2O和D2O中的激发态寿命测量证实了该阳离子与水分子的极佳屏蔽作用,其水合数为零。Tb配合物在水溶液中表现出高光致发光量子产率(24%,0.01 M Tris-HCl,pH 7.4)和非常长的发光寿命(2.6 ms)。活化配体与不同生物化合物如链霉亲和素和针对总前列腺特异性抗原(TPSA)的单克隆抗体进行了偶联。结合AlexaFluor647(AF647)和交联藻蓝蛋白(XL665)抗体偶联物,在血清样品中进行了基于时间分辨荧光共振能量转移(FRET)的TPSA免疫测定。Tb供体-染料受体FRET对提供了较大的Förster距离(5.3 nm,AF647;7.1 nm,XL665)。通过时间分辨FRET分析Tb供体和染料受体的光致发光衰减,揭示了在夹心免疫复合物中供体-受体平均距离分别为4.2 nm(AF647)和6.3 nm(XL665),且FRET效率分别为0.79和0.68。使用KRYPTOR荧光免疫分析仪测得的检测限非常低,为1.4 ng mL-1(43 pM)和2.4 ng mL-1(74 pM)TPSA。这些结果展示了我们新型Tb生物偶联物在高度敏感临床诊断中的应用潜力。