Cancer is a difficult disease to cure due to its diversity and complexity. Despite novel therapeutic approaches having been proposed in recent years, chemotherapy remains one of the most common treatment regimens to this day. Unfortunately, its anticancer effects are often quelled by the lack of selectivity; hence alteration of the activity of already existing drugs by combining them with potential modulators e.g. metallic nanoparticles has been proposed as a possible strategy to overcome this problem. Herein, we verified if platinum nanoparticles (PtNPs) of various sizes interact with daunorubicin (DAU), a chemotherapeutic agent used for the treatment of leukaemia. Utilizing DLS and NTA we observed nanoparticle aggregation upon addition of increasing concentrations of DAU. Furthermore, we noticed that PtNPs quench DAU's fluorescence, suggesting their direct interaction. Next, we used FTIR and NIR spectroscopies and registered significant changes in the obtained spectra in the presence of PtNPs. The ITC and DSC analyses showed that all tested sizes of PtNPs interact with DAU in an endothermic manner, with the enthalpy change between 0.47 and 4.36 kcal mol⁻¹. The release analysis employing the dialysis bag method evidenced that PtNPs influence DAU's diffusion kinetics, decreasing its release from 100% (when alone) to ca. 70% when combined with PtNPs. All tested sizes of PtNPs reduce DAU's mutagenicity towards S.enterica serovar Typhimurium TA98 strain, however, no significant influence on DAU's cytotoxicity was observed on neither MelJuSo nor HaCaT eukaryotic cell lines. Overall, these results indicate that PtNPs may affect DAU's biological activity and warrant further biological studies.

Virus-like particles (VLPs) have long been utilized as immunogens to prevent infectious diseases. Particles derived from the small surface proteins of the hepatitis B virus (sHBsAg) can self-assemble into small, highly immunogenic structures and have been used in human vaccination since the 1980s. Various chimeric sHBsAg VLPs retain their self-assembly ability, even when significant sequence alterations, such as fusions or substitutions, are introduced. This makes them an attractive experimental model and vaccine platform for delivering and presenting foreign epitopes. In the present study, motifs from the hepatitis B virus (HBV) core protein (HBcAg) were introduced into the cytosolic loops of sHBsAg to explore whether these VLPs could acquire the ability to pack mRNA. With one exception, the introduced changes for mRNA binding did not affect ability for self-assemble. A Twin-Strep-tag was added to the N-terminus for more efficient and specific purification. With the exception of one modification, the changes made to allow for mRNA binding did not affect the self-assembly capability of sHBsAg. The recombinant proteins successfully bound mRNAs from various sources.

Background/Objectives: Cancer remains one of the leading causes of death worldwide. Although chemotherapy is widely used, it is associated with severe side effects, including myelosuppression and systemic toxicity. Nanoparticles have emerged as promising candidates for modulating drug activity. In this study, we investigated whether platinum nanoparticles (PtNPs) of various sizes interact with idarubicin (IDA), an anthracycline anticancer drug used primarily to treat acute leukaemia. Methods: Interactions between PtNPs and IDA were analysed using dynamic light scattering (DLS), atomic force microscopy (AFM), fluorescence spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, and near-infrared (NIR) spectroscopy. Thermodynamic and thermal properties were assessed using isothermal titration calorimetry (ITC) and differential scanning calorimetry (DSC). Biological effects were evaluated using the Ames mutagenicity assay on the Salmonella enterica serovar Typhimurium TA98 strain and cytotoxicity assays on SK-BR-3 and MCF-7 cell lines. Results: DLS demonstrated changes in the hydrodynamic diameter of PtNPs following IDA addition, which were further supported by AFM imaging. PtNPs significantly quenched IDA fluorescence, indicating close molecular interactions, which were further supported by FTIR and NIR. ITC revealed that the interactions were endothermic, with enthalpy values ranging from 1.2 to 3.6 kcal/mol, and DSC demonstrated that the PtNP-IDA combination altered the melting temperature of IDA. Biological assays revealed that all examined PtNP sizes influenced IDA mutagenicity in the Salmonella enterica serovar Typhimurium TA98 strain. Furthermore, PtNPs modulated the cytotoxicity of IDA in SK-BR-3 and MCF-7 cell lines in a dose-dependent manner. Conclusions: These findings demonstrate that PtNPs interact with IDA and modulate its biological activity. However, in this study no non-cancerous cell lines were examined; therefore, the observed interactions and biological effects support further investigation of the PtNP-IDA combination in the context of nanoparticle-assisted anticancer therapy on a broader range of in vitro cell lines.