Vol 85, No 5 (2023)

Pulmonary surfactant, which is a complex mixture of lipids and proteins, plays a key role in the functional properties of the respiratory system. Lipids form complexes with proteins to maintain low values of surface tension at continuous compression/expansion deformations. However, interactions that lead to the complexation still remain to be unknown thus significantly hampering the development of synthetic analogs of the natural pulmonary surfactant. In this work, the methods of surface rheology and ellipsometry have been employed to study the dynamic properties of model phospholipid monolayers applied onto the surfaces of synthetic polyelectrolyte solutions. It has been shown, that electrostatic or hydrophobic interactions between lipids and macromolecules are insufficient for the efficient complexation and maintenance of low surface tension values.

The correlation between the time of preliminary storage of ultrasmall gold nanoparticles (GNPs) synthesized according to the Duff method and the structural aspects of their interaction with the particles of cholesteric liquid-crystalline dispersions (CLCDs) of DNA were studied. It has been established that the “age” of GNPs significantly affects the magnitude of their destructive action on the ordered organization of the DNA CLCD particles. The observed effect may be caused by both the gradual perfecting of the crystal lattice of the studied GNPs (i.e., their metallization) and the change in the chemistry of their surface over time.

Nanoemulsions (NEs) and solid lipid nanoparticles (SLNs) are promising drug delivery systems. In this work, paraffin oil NEs and stearic acid SLNs stabilized with Tween 60 and Span 60 have been studied. NEs with an average droplet diameter of ~50 nm and suspensions of SLNs with an average size of ~30 nm are stable to aggregation for more than 90 days. The rates of penetration of lipid particles into cancer cells (C6 and MCF-7) depend on their sizes. After incubation for 1 h, lipid nanoparticles ~50 nm in size penetrate into cells, are distributed in their internal space, and concentrate in the nuclei. The cytotoxicity of doxorubicin- or thymoquinone-loaded NEs and SLNs against MCF-7 and HTC 116 cell lines is higher than the cytotoxicity of the individual substances. Wherein, unloaded NEs and SLNs show low cytotoxicity. The obtained results demonstrate that paraffin oil NEs and stearic acid SLNs are promising to be used as carriers of both lipophilic and amphiphilic drugs, including doxorubicin and thymoquinone. The accumulation of lipid nanoparticles with sizes smaller than 100 nm in cell nuclei is an advantage of such systems for the delivery of anticancer drugs, because this leads to DNA replication suppression followed by cell apoptosis.

Bacterial health care-associated infections (HCAI) are one of the acute problems of modern healthcare. One of the promising directions for solving this problem is the development of materials that either have a bactericidal effect against HCAI pathogens or prevent the transmission of bacteria deposited on their surface by patients and staff contacts with such surfaces. In this work, the antibacterial effectiveness of copper contact surfaces with different wettability was investigated. Particular attention was paid to studying the effect on this efficacy of surface contamination by both human contact sweat and bacterial life-supporting substances, using a peptone solution as an example. Due to the high cost of copper, the possibility of replacing bulk copper material with less expensive sprayed copper-coated materials was also investigated. The test results showed that the bactericidal efficacy against Staphylococcus aureus strain of both control copper and superhydrophilic copper samples, as well as of sputtered copper films, is close to 100% and almost unchanged after contamination with peptone solution or sweat excretions. Superhydrophobic copper surfaces have less bactericidal efficacy, but due to the non-wettability effect and low cell adhesion to such surfaces, they remain uncontaminated longer and thus also promote reducing the transmission of infections through the touch surfaces made of them.

For the first time, stable aqueous colloidal solutions of cerium dioxide stabilized with L-malic acid have been obtained at ligand : CeO2 molar ratios of 0.2, 0.5, 1.0, and 2.0. Using dynamic light scattering, it has been shown that CeO2 sols are characterized by a narrow monomodal size distribution of aggregates, and the sols remain to be aggregatively stable in a Tris-HCl buffer solution. According to the chemiluminescence analysis of the enzyme-like activity of cerium dioxide sols with respect to hydrogen peroxide, the surface modification of the cerium dioxide particles with malic acid increases the enzyme-like activity of СеО2 up to 4.5 times.

Recently, lipid nanoparticles have been intensively studied as carriers of lipophilic drugs. In this work, we have studied the stability of nanoemulsions with paraffin oil, solid lipid nanoparticles with stearic acid, and nanostructured lipid particles with paraffin oil and stearic acid in a mass ratio of 1 : 1. The obtained results have shown that all studied lipid systems stabilized with nonionic surfactants Tween 60 and Span 60 were stable to aggregation and subsequent sedimentation for more than 30 days. The incorporation of lutein into the lipid particles has almost no effect on their stability, while the size of solid lipid nanoparticles and nanostructured lipid nanoparticles decreases from 28–30 to 15–17 nm. The bioavailability of lutein loaded in lipid nanoparticles is evaluated from their effect on the restoration of blood flow velocity by simulating hemic hypoxia. Almost immediately after the application of lipid nanoparticles, the blood flow velocity ceases to decrease, and a tendency to its restoration is observed in 5–10 min. This shows that lipid nanoparticles with paraffin oil and stearic acid are promising candidates for the delivery of lipophilic drugs.