We report on the unique self-assembling properties of one molybdacarborane (1) and two ruthenacarborane complexes (2 and 3) to spontaneously form nanoparticles alone or in combination with bovine serum albumin (BSA) in a 10:1 molar ratio (BSA:metallacarborane). The maverick behaviour of the metallacarboranes in aqueous media was investigated using several spectroscopic techniques, including nanoparticle tracking analysis, UV-Vis, fluorescence, Rayleigh light scattering and NMR spectroscopy, as well as MALDI-TOF mass spectrometry, from which a molecular picture of the nanoparticles was developed. The metallacarborane–albumin nanoparticles showed optimal stability in phosphate buffer (pH 7.4), retaining a mostly monomodal dispersion over 24 h, in contrast to the highly polydispersed nanoparticles of 1–3 alone. The three metallacarboranes were tested in vitro against the MCF-7 (breast carcinoma) cell line, using a BSA-free and a BSA-containing formulation. Surprisingly, the latter induced a significant increase in the cytotoxicity of 1, whereby it did not greatly affect the activity profile of 2 and 3. Finally, label-free confocal Raman imaging was applied to visualise the uptake of the metallacarboranes into single cells. The size of intracellular aggregates in the cytoplasm ranged from 300 nm to 5 μm. The discussed formulation concept is proposed as a new method to increase the bioactivity and the biological stability of poorly water-soluble (metalla)carboranes.

我们报告了一种钼碳硼烷（1）和两种钌碳硼烷络合物（2和3）的独特自组装性能）以10：1的摩尔比（BSA：金属碳硼烷）单独或与牛血清白蛋白（BSA）结合自发形成纳米颗粒。使用几种光谱技术研究了金属碳硼烷在水介质中的特立独行行为，包括纳米粒子跟踪分析，UV-Vis，荧光，瑞利光散射和NMR光谱，以及MALDI-TOF质谱，从中可得出分子图。纳米粒子被开发出来。金属碳硼烷-白蛋白纳米颗粒在磷酸盐缓冲液（pH 7.4）中显示出最佳的稳定性，在24小时内保持了大部分单峰分散，与1-3高度分散的纳米颗粒相反单独。使用不含BSA和含BSA的制剂在体外针对MCF-7（乳腺癌）细胞系测试了三种金属碳硼烷。出人意料的是，后者诱导了1的细胞毒性的显着增加，因此它并未极大地影响2和3的活性。最后，应用无标记共聚焦拉曼成像技术，以观察金属碳硼烷吸收到单个细胞中的情况。细胞质中细胞内聚集体的大小为300 nm至5μm。提出了讨论的制剂概念，作为增加水溶性差的（金属）碳氢化合物的生物活性和生物稳定性的新方法。