Instytut Chemii I Techniki Jadrowej

Extracting radionuclides from natural and anthropogenic sources addresses two challenges: remediating contaminated environments and enabling the separation of technologically important isotopes. Understanding how actinides interact and form complexes with polymer-based ligands allows the development of efficient extractants for selective remediation, supporting sustainable environmental protection and resource recovery strategies. Here, we report on the structure and actinide sorption properties of eco-friendly hybrid nanocomposite systems based on the natural mineral halloysite and multifunctional conjugated polymers. Three polyaniline (PANI)-based polymers and their nanocomposites with halloysite nanotubes (HNT) were synthesized and evaluated as sorbents for removing uranium and plutonium from aqueous solutions. The study included two PANI variants synthesized at high (60 °C) and low (1-2 °C) temperatures using different acid-dopants, H₂SO₄ and p-toluenesulfonic acid, and a PANI copolymer incorporating aminoterephthalic acid (PANIATA), which introduces carboxylic functional groups. X-ray photoelectron spectroscopy and electron microscopy revealed the formation of core-shell nanocomposites with HNT as the core and a polymer shell several nanometers thick. The HNT/PANI nanocomposites exhibited a synergistic enhancement in actinide retention capacity, exceeding the additive performance of the individual components. Sorption experiments with artificial groundwater and seawater confirmed the nanocomposites' selectivity for uranium. Analysis of the FTIR spectra of the polymer composites before and after uranium sorption provided detailed insight into uranyl cation-polymer complexation mechanisms responsible for high selectivity and sorption performance.

The DNA damage response (DDR) of cells to low dose and low dose rate ionizing radiation is weak and remains a matter of controversy. The response can be studied by exposing cells to a low adapting dose (AD) and, subsequently to a high challenging dose (CD), where the response is strong. The aim of the present investigation was to analyse the DDR in cells exposed to very low dose rate AD and a high dose rate CD, with special focus on the role of the ATM kinase. U2OS cells (with wild type p53) were exposed to gamma radiation AD of 5.9 mGy at 31 µGy/h and of 10.5 mGy at 55 µGy/h. ATM was inhibited by addition of KU-55933. Adapted cells were exposed to a CD of 1 Gy photon radiation at 1 Gy/min. The studied endpoints included kinetics of 53BP1 foci formation and decay, cell cycle progression and gene expression. In some experiments, ATM was inhibited by KU-55933. AD alone led to a significant increase in 53BP1 foci, even in the presence of KU-55933, and it modulated the response to CD. KU-55933 failed to inhibit the induction of foci by AD and AD+CD, while foci induction by CD alone was inhibited. KU-55933 potentiated the G2 block in AD+CD-exposed cells. Gene expression was modulated by AD. In conclusion, AD differentially modulated the response of cells when given alone and after the CD, in absence and presence of KU-55933.

One modern concept for cancer treatment is the use of antibody-drug conjugate (ADC). These therapies have shown promising results, especially in combination with other cancer treatment techniques. In this study, we propose the simultaneous use of β^- radiation (¹⁹⁸AuNPs) and trastuzumab emtansine (T-DM1; Kadcyla) for targeted therapy of cancers with established HER2 receptor overexpression. By utilizing ¹⁹⁸AuNPs-T-DM1, we aimed to reduce the required concentrations of T-DM1, which is advantageous given the associated emtansine-related side effects. In our study, we demonstrated the affinity of conjugated ¹⁹⁸AuNPs-T-DM1 for HER2 receptors and its effective internalization. In vitro studies indicate a synergistic therapeutic effect at doses of 10 MBq/mL or 20 MBq/mL of radiation and low concentrations of Kadcyla ranging from 0.015 to 0.124 μg/mL. Treatment with ¹⁹⁸AuNPs-T-DM1 at 20 MBq/mL and T-DM1 concentration of 0.031 μg/mL disintegrated 3D spheroid structures within seven days. The synthesized ¹⁹⁸AuNP-T-DM1 radiobioconjugate has potential applications in nuclear medicine for treating breast or ovarian cancers with HER2 receptor overexpression.