In this study, we aimed to develop a technique for colloidal silver nanoparticle (AgNP) modification in order to increase their stability in aqueous suspensions. For this purpose, 40-nm spherical AgNPs were modified by the addition of either human albumin or Tween-80 (Polysorbate-80). After detailed characterization of their physicochemical properties, the hemolytic activity of the nonmodified and modified AgNPs was investigated, as well as their cytotoxicity and antimicrobial effects. Both albumin- and Tween-80-coated AgNPs demonstrated excellent stability in 0.9% sodium chloride solution (>12 months) compared to nonmodified AgNPs, characterized by their rapid precipitation. Hemolytic activity of nonmodified and albumin-coated AgNPs was found to be minimal, while Tween-80-modified AgNPs produced significant hemolysis after 1, 2, and 24 h of incubation. In addition, both native and Tween-80-covered AgNPs showed dose-dependent cytotoxic effects on human adipose-tissue-derived mesenchymal stem cells. The albumin-coated AgNPs showed minimal cytotoxicity. The antimicrobial effects of native and albumin-coated AgNPs against S. aureus, K. pneumonia, P. aeruginosa, Corynebacterium spp., and Acinetobacter spp. were statistically significant. We conclude that albumin coating of AgNPs significantly contributes to improve stability, reduce cytotoxicity, and confers potent antimicrobial action.

Fluorescence imaging is a promising method widely used for the evaluation of the biodistribution and accumulation of various fluorescent agents cross-linked to the drug for effective therapy control. This work presents the methods for the functionalization of nanomaterials to provide them with fluorescent properties. The first of these methods is a unique technology for producing porous silicon with fluorescent properties. The second approach demonstrates linking of the fluorophores to inorganic nanoparticles (NP) using a spacer molecule ending with a functional group. For all these examples of fluorophores, biodistribution studies were performed with the fluorescent imaging system IVIS Lumina LT III (PerkinElmer, USA). It was noted that the size of particles and the method of their injection affect the distribution and accumulation in organs. The resulting materials can be used to develop platforms for theranostics.

The overuse of antibiotics has led to the emergence of resistant bacteria. A good alternative is silver nanoparticles, which have antibacterial activity against Gram-negative and Gram-positive bacteria, including multidrug-resistant strains. Their combination with already known antibiotics has a synergistic effect. In this work, we studied the synthesis of conjugates of silver nanoparticles with two antibiotics, lincomycin and cefazolin. Albumin and glutathione were used as spacer shells with functional groups. The physicochemical properties of the obtained conjugates, their cytotoxicity and synergism of antimicrobial activity were studied. The 50% antimicrobial activity of the obtained samples was shown, which allows them to be recommended for use as topical drug preparations.

The aim of the present study was to develop magnetic liposomes (MLPSs) incorporating an agent with the ability to act both as a photosensitizer and as a fluorophore for optical imaging. We therefore aimed to develop a preparation method for indocyanine green (ICG)-containing MLPS, followed by a detailed characterization of their physicochemical and magnetic properties. The ability of intravenously administered ICG-containing MLPSs to accumulate in tissue exposed to a constant magnetic field was tested in vivo. Using the thin film hydration method, 170-nm aqueous liposomes containing magnetic nanoparticles and indocyanine green were synthesized, followed by a detailed characterization of their physicochemical properties. It was shown that ICG-containing MLPSs possess the properties of T2 contrast for MRI. Apart from this, ICG-containing MLPSs were clearly visualized using near infrared fluorescent imaging, which was demonstrated in in vivo experiments showing an accumulation of ICG-containing MLPSs in the zone of magnetic field distribution produced by a previously implanted constant magnet in the tissue. Although not directly tested in the present study, therapeutic applications of ICG-containing MLPSs include magnetic hyperthermia, as well as the photodynamic, photothermal, and photoacoustic effects of ICG. Taking into account the fact that liposomes, iron oxide nanoparticles, and ICG are all FDA-approved agents, it is highly likely that ICG-containing MLPSs could be successfully translated to clinical practice.