Nuclear energy is experiencing a worldwide scientific and economic revival to support the fight against global carbon emissions. The various operations associated with the nuclear sector always come with a risk of exposure to radionuclides (RNs). In case of contamination, the available medical countermeasures rely on chelating molecules to sequester and remove RNs from the body. Unfortunately, the current family of clinically approved decorporation agents is limited to a single member (polyaminocaboxylic acid,DTPA) that has been shown to remove plutonium. Currently, there are no clinically proven strategies to decorporate RNs such as uranium (U), cesium (Cs), strontium (Sr), or cobalt (Co). Therefore, it is imperative to continue the search for new potential candidates for the decorporation of the above-mentioned elements. The scrutinized chelating molecules must then be ranked according to their selectivity and affinity for the different RNs to select the best candidates. As with any harmful substance or one that is simply available in limited quantities, it is crucial to minimize the amount of material involved. Following this logic, this project aims to develop a multiplex miniaturized device to measure the affinity and selectivity of chelating molecules towards the RNs of interest. Based on the previously published work [1], we are synthesizing 8 mm long phosphate-functionalized monoliths covalently grafted to the inner surface of silica capillaries. Such monoliths have high affinity for U, and can capture over 20 µg of U per cubic millimetre of volume, as measured by capillary-coupling to ICP-MS. In our system, each of the four channels is being explicitly dedicated to the immobilization of U, Cs, Sr, and Co. By immobilizing U, Cs, Sr, and Co in the channels of our device, we’re effectively transforming them into versatile metal affinity supports. The coupling of the microsystem to ICP-MS and ESI-MS allows us to determine the RN-loading capacity of each monolith in combination with the chelating power of the eluted molecules according to their affinity for the immobilized RNs. The most promising chelator-RN couples will be subject to additional ex-vivo and in-vitro tests in physiological conditions.

[1] S. Barhoum et al. Immobilization of controlled Pu:Am ratio on actinide-specific affinity monolith support developed in capillary and coupled to inductively coupled plasma mass spectrometry, Microchimica Acta, 2024, 191(4), 191.