This review presents an overview of the successes and challenges currently faced in alpha radionuclide therapy. Alpha particles have an advantage in killing tumour cells as compared to beta or gamma radiation due to their short penetration depth and high linear energy transfer (LET). Touching briefly on the clinical successes of radionuclides emitting only one alpha particle, the main focus of this article lies on those alpha-emitting radionuclides with multiple alpha-emitting daughters in their decay chain. While having the advantage of longer half-lives, the recoiled daughters of radionuclides like ²²⁴Ra (radium), ²²³Ra, and ²²⁵Ac (actinium) can do significant damage to healthy tissue when not retained at the tumour site. Three different approaches to deal with this problem are discussed: encapsulation in a nano-carrier, fast uptake of the alpha emitting radionuclides in tumour cells, and local administration. Each approach has been shown to have its advantages and disadvantages, but when larger activities need to be used clinically, nano-carriers appear to be the most promising solution for reducing toxic effects, provided there is no accumulation in healthy tissue.

A great number of fluorescent probes have been developed for detecting singlet oxygen (¹O₂), which is considered to be one of the most effective reactive oxygen species (ROS), especially in clinical applications. The commercially available fluorescent probe Singlet Oxygen Sensor Green (SOSG) is widely used due to its reported high selectivity to ¹O₂. In this study, we carried out systemic experiments to determine the activation of SOSG in the presence of ionizing radiation. The results show that the SOSG probe exhibits a pronounced fluorescence increase as a function of radiation dose delivered by gamma-rays as well as X-rays, in conditions where the formation of singlet oxygen is not expected. Furthermore, scavenger tests indicate that hydroxyl radicals may be involved directly or indirectly in the activation process of SOSG although the exact mechanism remains unknown.

Four different MOFs were exposed to γ rays by a cobalt-60 source reaching a maximum dose of 5 MGy. The results showed that the MIL-100 (Cr) and MIL-100 (Fe) did not exhibit obvious structural damage, suggesting their excellent radiation stability. MIL-101 (Cr) showed good radiation stability up to 4 MGy, but its structure started degrading with increasing radiation dose. Furthermore, the results showed that the structure of AlFu MOFs started to decompose at a gamma dose of 1 MGy, exhibiting a much lower tolerance to γ radiation. At this radiation energy, the dominant interaction of the gamma-ray with MOFs is the Compton effect and the radiation stability of MOFs can be improved by prolific aromatic linkers, high linker connectivity, and good crystallinity. The results of this study indicate that MIL-100 and MIL-101 MOFs have a good potential to be employed in nuclear applications, where relatively high radiation doses play a role, for example, nuclear waste treatment and radionuclides production.

The morphologies and sizes of micellar aggregates, composed of the tri-block copolymer P123 (EO₂₀PO₇₀EO₂₀) in a mixture of the aprotic solvent N,N-dimethylformamide (DMF) and water, were investigated by combining Dynamic Light Scattering (DLS) and Cryogenic Transmission Electron Microscopy (cryo-TEM) experiments. At water concentrations between about 27 and 35 wt% bicontinuous micelles with distinct patterns were formed, in coexistence with very long, non-branched, worm-like micelles. Water concentration affects both the size and the morphology of the micellar aggregates. A careful study of the pure binary solvent mixture revealed the presence of dynamic solvent domains of nanometric size, even in the absence of copolymer. Strikingly, the size of these solvent nano-domains closely matched the size of the bicontinuous micelles in a polymer solution for the same water/DMF ratios. We discuss these findings in terms of spinodal decomposition of the polymer solution, in which two-solvent domains contain solvent quality fluctuations that could determine the decomposition. In addition, we suggest another “soft confinement” mechanism that could be responsible for the formation of bicontinuous micelles. The local excess of one of the solvent species in the nano-domains could entrap a metastable morphology.