The following work describes the synthesis of new physical filters based on TiO₂/SiO₂ and TiO₂/Ag nanostructures. Titanium dioxide nanoparticles (TiO₂ NPs) were applied as control material and a popular physical UV filter. The advantage of using materials on the nanometer scale is the elimination of the skin whitening effect that occurs when using photoprotective cosmetics containing titanium dioxide on a macro scale. In addition, the silica coating makes the material less harmful, and the silver coating enriches the material with antibacterial properties. Nanoparticles and nanostructures have been characterized by Energy Dispersive X-Ray Analysis (EDX), the Scanning Electron Microscope (SEM), Transmission Electron Microscopy (TEM), and Fourier-Transform Infrared Spectroscopy (FT-IR) methods. Due to the use of physical filters in anti-radiation protection cosmetics, water-in-oil (W/O) emulsion has been prepared. All cosmetic formulations have been tested for stability. The sun protection research with the Sun Protection Diagnostic SP37 was carried out. These studies made it possible to determine the natural sun protection time and to compare the synthesized materials. Furthermore, one of the most important parameters when describing this type of cosmetic is water resistance, which has also been measured. The results show that the new type of material of TiO₂/Ag used as a new physical filter in emulsion W/O shows the best sun protection compared with other obtained nanomaterials. It is most likely due to the improved optical properties of the combination of noble metals, for example, silver with TiO₂.

The medical and cosmetic industries have developed in recent years, and there has been a growing demand for new materials. Gold nanoparticles (AuNPs) and chitosan (CS) have been known and used for many years. Unfortunately, despite their numerous advantages and possible applications, such materials may possess certain disadvantages and limitations that constitute a problem in medical or cosmetic applications. Au NPs may have potential toxicity depending on their size, shape, charge, surface coatings, and tendency to agglomerate into larger clusters. On the other hand, the CS production process requires strict control due to the possibility of uncontrolled hydrolysis or chemical modifications during polymer isolation. The combination of Au NPs and CS that differ in chemical and phase in one composite (Au NPs/CS) allows for acquiring of new material with many advantages. The obtained composite has good mechanical properties and is biocompatible due to the presence of CS and the antibacterial properties of Au NPs. Therefore, it can be successfully used in many branches of medicine, including gene delivery, cell encapsulation, wound healing process, or as a preservative ingredient of cosmetics. Moreover, Au/CS nanocomposites are used in the food industry and environmental protection. This review highlights the preparation routes, properties, and applications of Au NPs and CS as separate materials. Moreover, the last part presents the advantages of combining these two materials into one nanocomposite. Specifically, we described the role of CS in the synthesis of Au NPs and possible subsequent applications of such nanomaterials as an element of biosensors, scaffolds, and an intelligent drug release system or tissue engineering.

Nanotechnology offers innovative strategies for developing multifunctional cosmetic ingredients. Here, we synthesize Au@SiO₂ and Ag@SiO₂ core–shell nanostructures with high shape and size uniformity, colloidal stability, and hydrophilicity. The silica shell stabilizes the metal core and enables surface functionalization, enhancing applicability in biopolymer-based formulations. We characterize the nanomaterials using UV–Vis spectroscopy, TEM, DLS, zeta potential, and contact angle measurements, confirming well-defined core–shell morphology and favorable surface properties. Both nanostructures display comparable antioxidant activity, while Ag@SiO₂ exhibits superior catalytic efficiency. To evaluate delivery performance, we incorporate the nanoparticles into sodium hyaluronate (HA) and hydroxyethylcellulose (HEC) hydrogels. The hybrid gels maintain homogenous morphology and enable tunable nanoparticle release profiles: HA gels promote rapid release and significantly improve skin hydration, whereas HEC gels provide sustained release suitable for prolonged action. These results demonstrate that Au@SiO₂ and Ag@SiO₂ nanostructures act as versatile, stable, and bioactive components for cosmetic and biomedical formulations. The study highlights the potential of core–shell nanomaterials at soft matter interfaces, combining antioxidant and antimicrobial functionality with controlled delivery and enhanced skin barrier performance.

Neurodegenerative diseases, particularly Parkinson's disease (PD), remain a major clinical challenge due to the limited efficacy and side effects of current therapies. L-DOPA, the gold-standard drug for PD, suffers from low stability, poor bioavailability, and neurotoxicity upon prolonged use. To address these limitations, we report the design, synthesis, and evaluation of a silica-coated gold core–shell nanosystem (Au@SiO₂) as a nanocarrier for the controlled delivery of L-DOPA. The nanostructures were synthesized via a bottom-up approach, stabilized with polyvinylpyrrolidone (PVP), and thoroughly characterized using TEM, UV-Vis, DLS, ELS, contact angle measurements, and electrochemical techniques. Despite modest L-DOPA loading efficiency (∼3%), the system demonstrated controlled and sustained drug release, with a marked difference between PVP-modified and unmodified systems. The nanocarrier exhibited high colloidal stability, hydrophilicity, and redox-protective effects over time, mitigating oxidative stress induced by L-DOPA, as well as minimal interaction with DNA. In vitro studies on SH-SY5Y cells confirmed good biocompatibility and a potential protective effect against oxidative stress, as evidenced by GSH : GSSG ratios and SOD activity. This multifunctional nanosystem offers a promising platform for brain-targeted drug delivery, combining biocompatibility, sustained release, and antioxidant-like activity reflected in the modulation of cellular redox balance (GSH/GSSG, SOD) – key advantages for next-generation neurotherapies.