[44/47Sc]Sc3+, [68Ga]Ga3+, and [111In]In3+ are the three most attractive trivalent smaller radiometalnuclides, offering a wide range of distinct properties (emission energies and types) in the toolbox of nuclear medicine. In this study, all three of the metal ions are successfully chelated using a new oxine-based hexadentate ligand, H3glyox, which forms thermodynamically stable neutral complexes with exceptionally high pM values [pIn (34) > pSc (26) > pGa (24.9)]. X-ray diffraction single crystal structures with stable isotopes revealed that the ligand is highly preorganized and has a perfect fit to size cavity to form [Sc(glyox)(H2O)] and [In(glyox)(H2O)] complexes. Quantitative radiolabeling with gallium-68 (RCY > 95%, [L] = 10-5 M) and indium-111 (RCY > 99%, [L] = 10-8 M) was achieved under ambient conditions (RT, pH 7, and 15 min) with very high apparent molar activities of 750 MBq/μmol and 650 MBq/nmol, respectively. Preliminary quantitative radiolabeling of [44Sc]ScCl3 (RCY > 99%, [L] = 10-6 M) was fast at room temperature (pH 7 and 10 min). In vitro experiments revealed exceptional stability of both [68Ga]Ga(glyox) and [111In]In(glyox) complexes against human serum (transchelation <2%) and its suitability for biological applications. Additionally, on chelation with metal ions, H3glyox exhibits enhanced fluorescence, which was employed to determine the stability constants for Sc(glyox) in addition to the in-batch UV-vis spectrophotometric titrations; as a proof-of-concept these complexes were used to obtain fluorescence images of live HeLa cells using Sc(glyox) and Ga(glyox), confirming the viability of the cells. These initial investigations suggest H3glyox to be a valuable chelator for radiometal-based diagnosis (nuclear and optical imaging) and therapy.

中文翻译：

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一触即发的螯合：为较小的放射性金属离子优化配体。

[44 / 47Sc] Sc3 +，[68Ga] Ga3 +和[111In] In3 +是三种最具吸引力的三价较小的放射性金属核素，在核医学工具箱中提供了广泛的不同特性（发射能和类型）。在这项研究中，所有三种金属离子均使用一种新的基于牛磺酸的六齿配体H3glyox成功螯合，形成了热力学稳定的中性配合物，具有极高的pM值[pIn（34）> pSc（26）> pGa（24.9） ]。具有稳定同位素的X射线衍射单晶结构表明，该配体高度组织化，非常适合于尺寸腔，从而形成[Sc（glyox）（H2O）]和[In（glyox）（H2O）]配合物。在环境条件（室温，pH 7）下，用镓68（RCY> 95％，[L] = 10-5 M）和铟111（RCY> 99％，[L] = 10-8 M）进行定量放射性标记。 ，和15分钟）具有非常高的表观摩尔活性，分别为750 MBq /μmol和650 MBq / nmol。[44Sc] ScCl3的初步定量放射性标记（RCY> 99％，[L] = 10-6 M）在室温下（pH 7和10分钟）快速进行。体外实验表明[68Ga] Ga（glyox）和[111In] In（glyox）配合物对人血清的稳定性极佳（转运不足2％），并且适用于生物学应用。此外，在与金属离子螯合时，H3乙二醛显示出增强的荧光，除批内UV-可见分光光度滴定法外，还可用于确定Sc（乙二醛）的稳定性常数。作为概念验证，这些复合物用于通过Sc（glyox）和Ga（glyox）获得活HeLa细胞的荧光图像，从而确认了细胞的活力。