Vaginal drug delivery systems can provide a long-term and constant liberation of the active pharmaceutical ingredient even for months. For our experiment, FDM 3D printing was used to manufacture the vaginal ring samples from thermoplastic polyurethane filament, which enables fast manufacturing of complex, personalized medications. 3D printing can be an excellent alternative instead of industrial manufacturing, which is complicated and time-consuming. In our work, the 3D printed vaginal rings were filled manually with jellified metronidazole or chloramphenicol for the treatment of bacterial vaginosis. The need for manual filling was certified by the thermogravimetric and heatflow assay results. The manufactured samples were analyzed by an Erweka USP type II Dissolution Apparatus, and the dissolution profile can be distinguished based on the applied jellifying agents and the API’s. All samples were considered non-similar based on the pairwise comparison. The biocompatibility properties were determined by prolonged MTT assay on HeLa cells, and the polymer could be considered non-toxic. Based on the microbiological assay on E. coli metronidazole and chitosan containing samples had bactericidal effects while just metronidazole or just chitosan containing samples bacteriostatic effect. None of these samples showed a fungistatic or fungicide effect against C. albicans. Based on our results, we successfully manufactured 3D printed vaginal rings filled with jellified metronidazole.

In this work, the effects of femtosecond laser irradiation and doping with plasmonic gold nanorods on the degree of conversion (DC) of a urethane dimethacrylate (UDMA)–triethylene glycol dimethacrylate (TEGDMA) nanocomposite were investigated. The UDMA-TEGDMA photopolymer was prepared in a 3:1 weight ratio and doped with dodecanethiol- (DDT) capped gold nanorods of 25 × 75 or 25 × 85 nm nominal diameter and length. It was found that the presence of the gold nanorods alone (without direct plasmonic excitation) can increase the DC of the photopolymer by 6–15%. This increase was found to be similar to what could be achieved with a control heat treatment of 30 min at 180 °C. It was also shown that femtosecond laser impulses (795 nm, 5 mJ pulse energy, 50 fs pulse length, 2.83 Jcm⁻² fluence), applied after the photopolymerization under a standard dental curing lamp, can cause a 2–7% increase in the DC of undoped samples, even after thermal pre-treatment. The best DC values (12–15% increase) were obtained with combined nanorod doping and subsequent laser irradiation close to the plasmon resonance peak of the nanorods (760–800 nm), which proves that the excited plasmon field can directly facilitate double bond breakage (without thermoplasmonic effects due to the short pulse length) and increase the crosslink density independently from the initial photopolymerization process.

Gold nanoparticles (AuNPs) display surface plasmon resonance (SPR) as a result of their irradiation at a targeted light frequency. SPR also results in heat production that increases the temperature of the surrounding environment, affecting polymerization. The aim was to investigate the SPR effect of AuNPs on a dimethacrylate-based photopolymer system. The tested composites were designed to overlap the illumination required for the polymerization and the plasmon effect. The 5 nm-sized dodecanethiol capped AuNPs were applied in different concentrations in the matrix that were irradiated with green light (λ = 532 nm), where the Irgacure 784 photoinitiator also absorbs the light. The plasmonic effect was investigated for the refractive index change by surface plasmon resonance imaging (SPRi) supplemented by ellipsometry. Moreover, optical transmission and transmission electron micrographs (TEM), diametral tensile stress (DTS), and confocal Raman spectroscopy was performed to determine the degree of conversion (DC) at 1.0, 1.4, and 2.0 mW/cm² light intensities. It was found that the optimal conditions were at 0.0208 wt% AuNPs concentration and 1.4 mW/cm² light intensity at which the refractive index change, DTS, and DC data were all maximal. The study confirmed that AuNPs are applicable to improve the polymerization efficiency of dental composite resin.

In this study, metallic nanoislands were prepared by thermal annealing of gold thin film produced by vacuum evaporation on a glass substrate to investigate the surface-enhanced Raman scattering (SERS) effect on them. The influence of the analyte on the enhancement factor of SERS was studied with riboflavin and rhodamine 6G dye. Two laser excitation sources at 532 and 633 nm wavelengths were used for SERS measurements. We found that the enhancement factors of the gold nanoisland SERS substrates were influenced by the analytes’ adsorption tendency onto their surfaces. The SERS amplification was also found to be dependent on the electronic structure of the molecules; higher enhancement factors were obtained for rhodamine 6G with 532 nm excitation, while for riboflavin the 633 nm source performed better.

The surface roughness, surface free energy (SFE) of composites, and composite wettability by dental adhesives are determining factors in achieving a strong and durable adhesion (e.g., composite repair, luting adhesively bonded indirect restorations). In this study, the SFE of one nanohydrid and two bulk-fill composites was investigated in relation to the wetting ability of five different dental adhesives. The profilometry and scanning electron microscopy (SEM) measurement justified that the sandblasting produced a significantly rough surface in which the different filler amounts, filler distribution, and resin-filler ratio participated. The SFE of the tested composite was between 45.65 and 49.07 mJ/m² regardless of surface treatment. Despite the similarity in SFE, the adhesives wet the surface of the composites in different ways that were between 16.01° and 35.10°. The contact angle of solvent-free dental adhesive was lower due to sandblasting supporting the micromechanical retention. Based on our results, it was found that sandblasting, the most frequently recommended surface treatment, does not change the surface energy but causes a change in the contact angle, which can be explained by the different surface tension of the dental adhesives. It was concluded that the dental adhesive parameters have a more important role in wettability.