Gold nanoparticles (GNPs) emerged as promising antitumor radiosensitizers. However, the complex dependence of GNPs radiosensitization on the irradiation conditions remains unclear. In the present study, we investigated the impacts of the dose rate and photon energy on damage of the pBR322 plasmid DNA exposed to X-rays in the presence of 12 nm, 15 nm, 21 nm, and 26 nm GNPs. The greatest radiosensitization was observed for 26 nm GNPs. The sensitizer enhancement ratio (SER) 2.74 ± 0.61 was observed at 200 kVp with 2.4 mg/mL GNPs. Reduction of X-ray tube voltage to 150 and 100 kVp led to a smaller effect. We demonstrate for the first time that the change of the dose rate differentially influences on radiosensitization by GNPs of various sizes. For 12 nm, an increase in the dose rate from 0.2 to 2.1 Gy/min led to a ~1.13-fold increase in radiosensitization. No differences in the effect of 15 nm GNPs was found within the 0.85–2.1 Gy/min range. For 21 nm and 26 nm GNPs, an enhanced radiosensitization was observed along with the decreased dose rate from 2.1 to 0.2 Gy/min. Thus, GNPs are an effective tool for increasing the efficacy of orthovoltage X-ray exposure. However, careful selection of irradiation conditions is a key prerequisite for optimal radiosensitization efficacy.

The creation of antibacterial nanocomposites that provide prolonged release of encapsulated drugs is of great interest for various fields of medicine (dentistry, tissue regeneration, etc.). This article demonstrates the possibility of creating such nanocomposites based on sodium alginate and drug-templated mesoporous silica nanocontainers (MSNs) loaded with two bioactive substances. Herein, we thoroughly study all stages of the process, starting with the synthesis of MSNs using antiseptic micelles containing the hydrophobic drug quercetin and ending with assessing the activity of the resulting composites against various microorganisms. The main emphasis is on studying the quercetin solubilization in antiseptic micelles as well as establishing the relationship between the conditions of MSN synthesis and micelle morphology and capacity. The effect of medium pH on the release rate of encapsulated drugs is also evaluated. It was shown that the MSNs contained large amounts of encapsulated drugs and that the rate of drug unloading depended on the medium pH. The incorporation of such MSNs into the alginate matrix allowed for a prolonged release of the drugs.

The modification of tantalum oxide (Ta₂O₅) nanoparticles (NPs) with biocompatible polymers is crucial for their biomedical use. Such modification can prolong NP circulation in the bloodstream by minimizing salt-induced aggregation and reducing nonspecific protein adsorption onto their surface. Understanding the features of polymer–NP interactions is a key issue in the fabrication of nanostructures with required characteristics. The present work aims to provide a comprehensive comparative study of bovine serum albumin (BSA) adsorption on bare and polydopamine (PDA)-coated Ta₂O₅ NPs. The synthesized NPs were characterized via transmission electron microscopy, Fourier transform infrared spectroscopy, dynamic light scattering, and zeta potential measurements. Fluorescence and circular dichroism spectroscopy were also employed for the first-time investigation of the interactions of Ta₂O₅ NPs and Ta₂O₅@PDA NPs with BSA. The results obtained show that PDA coating significantly enhances the protein-binding affinity. Time-resolved measurements revealed signatures of Förster resonance energy transfer, confirming complex formation between NPs and BSA. Moreover, colloidal stability tests in phosphate-buffered saline indicated that the presence of adsorbed BSA improves the dispersion stability of bare and PDA-coated Ta₂O₅ NPs. These findings advance the understanding of protein–NP interactions and highlight the potential of PDA coatings for designing stable and functional nanostructures for biomedical applications.