1. Introduction
Bimetallic nanoparticles synthesized by non-toxic methods have gained considerable spotlight in applications such as cancer therapy and target-specific drug delivery. This is due to material-specific properties provided by the shell, like metal-specific catalytic and electronic properties and core-associated stability, making them highly customizable. In this project, we successfully synthesized stable bimetallic core–shell particles of silver/selenium for potential applications in drug delivery/antimicrobial use.

2. Methods
Bimetallic nanoparticles of the silver core–selenium shell, and vice versa, were synthesized by a two-step bottom-up approach, using cinnamon, curcumin, and hibiscus plant extracts as part of the green synthesis protocol. Nanoparticles were characterized for size and morphology by UV–Vis spectroscopy, TEM, SEM, and Infra-red spectroscopy.

3. Results
Nanoparticles and raw materials were analysed for nanoparticle formation at each step of
synthesis using UV spectroscopy; the absorption spectra of the extracts were obtained so they could be excluded. Initial plasmon resonance peaks were seen at 285nm in line with the range of 200-350nm expected for selenium, indicating the formation of a selenium core. UV spectrometry was repeated once the silver shell was synthesized, encapsulating the core, and a peak was observed at 446nm in addition to a pre-existing peak at 285nm, inline with expected peaks for silver in the 400-800nm range, indicating the formation of a silver shell. Results were further confirmed with SEM/TEM imaging.

4. Conclusion
Stable bimetallic core–shell nanoparticles were synthesized using plant extracts that acted not only as catalytic compounds but also simultaneous reducing and stabilising agents within the synthesis process, were successfully prepared using inexpensive and eco-friendly methods, as evidenced by UV spectrometry and SEM/TEM imaging showing the presence of spherical nanoparticles measuring under 100nm. Antimicrobial sensitivity testing and further stability testing is currently underway.

Introduction

Currently, the high mortality rate of invasive fungal diseases worldwide poses a significant threat to human life and health. However, the antifungal resistance and the blood-brain barrier (BBB) severely limit the treatment options and success rate of clinical management for fungal infections, especially meningitis. Host defense peptides are an ideal class of antibiotic alternatives, but the poor proteolytic stability, difficult synthesis, and expensiveness hinder their applications. It is also difficult to find highly selective antifungal and BBB-penetrating HDP mimics because fungi and mammalian cells are both eukaryotic cells. Inspired by cell-penetrating peptides (CPP), which could penetrate the cell membrane and BBB, we hypothesize that the mimics of both HDP and CPP could penetrate the fungal cell membrane and BBB to realize potent antifungal activity against meningitis.

Methods

A series of guanylated poly(2-oxazoline)s were synthesized by mimicking HDP and CPP. The in vitro and in vivo studies were conducted to realize therapeutic effects against invasive fungal infections and fungal meningitis.

Results

The guanylated poly(2-oxazoline)s PGOx₁₀ displayed efficient and selective antifungal properties against drug-resistant fungi by penetrating the fungal membrane to induce fungal organelle decomposition (Angew. Chem. Int. Ed., 2022, 61, e202200778). PGOx₁₀ also demonstrated potent therapeutic potential in several infection models, including the skin abrasion infection, model, keratitis model, and systemic infection model. By adjusting the side-chain spacers, we found that guanylated poly(2-oxazoline)s PGMeOx₁₀ with methyl spacer group showed more potent antifungal activity, as well as BBB-penetrating property (J. Am. Chem. Soc. 2023, 145, 25753-25765). Therefore, PGMeOx₁₀ displayed anti-infectious activity against fungal meningitis.

Conclusions

This study proposes a novel strategy for designing highly effective and selective antifungal agents and offers potential candidate compounds for combating invasive fungal infections and meningitis.

With pronounced optical absorption and scattering, metal nanoparticles (MetNPs), such as gold (Au), silver (Ag), and copper (Cu), have found their way into a wide spectrum of applications, from biological to electrochemical. The effects that are the most important characteristics of these particles—the localized surface plasmon resonance (SPR) and high surface reactivity—are closely related to their physico-chemical features (size, shape, high percentage of unsaturated surface atoms, surface charge, medium, etc.), allowing researchers to design nanostructures tailored to specific biomedical applications based on a variety of biological processes occurring on the nanometer scale. The goal of this work is to present the abovementioned NPs with different sizes and shapes as free-standing or functionalized (by polymers—polyaniline and polypyrrole—or mesoporous silica) NPs, presenting an interesting and useful antimicrobial activity as one of their many beneficial features for application in biological systems. Besides NPs’ incorporation into polymers/silica protecting them from agglomeration and oxidation, their functionalization also improves their properties, making them, among other things, biocompatible and water-soluble materials that are easily synthesized with an excellent yield. Considering these antimicrobial biomaterials, additional attention should be paid to their cytotoxicity, environmental impact, and long-term stability, as well as potential microbial resistance development.

Acknowledgment: The research was funded by the Ministry of Science, Technological Development and Innovation of the Republic of Serbia, via direct financing of the Vinča Institute of Nuclear Sciences - National Institute of the Republic of Serbia (contract number: 451-03-66/2024-03/200017).

Introduction: Innovative fluoride-doped calcium phosphates attract great interest as potential remineralising materials for dental applications, which may be able to react with body fluid and be converted into fluorapatite (FA) and/or fluor-hydroxyapatite (FHA). Hence, this in vitro study aimed to assess the cytotoxicity, self-renewal, and migratory properties of these experimental materials.

Methods: Five specimens containing 0, 5, 10 and 20% fluoride on hDPSCs were tested at different dilutions (undiluted, from 1:5 to 1:100), and the eluates were prepared according to ISO 10993-12. Viability assays were conducted using the MTT test. Furthermore, we analysed self-renewal by observing colony formation and migration activity with scratch tests.

Results: Our results demonstrated that the powders with greatest toxicity on hDPSCs are those without fluoride and with 20% fluoride when diluted 1:1. Exclusively using the 1:50 dilution, which is non-cytotoxic, we observed that the powder containing 20% fluoride caused a significant decrease in clonogenic capacity. Furthermore, the results obtained from the scratch test did not highlight significant differences in terms of the migratory capacity of the cells when treated with different percentages of fluoride, leaving us to hypothesise that the different percentages of fluorine do not act at the level of the cytoskeleton.

Conclusions: The results obtained confirm that the experimental fluoride-doped calcium phosphates are cytotoxic for hDPSCs regardless of the percentages of fluorine tested, but the effects of their dilutions indicate that controlled doses could be able to promote cell proliferation. Therefore, the data obtained represent a starting point for future studies that will focus on the most appropriate concentrations of fluoride to be used in order to obtain non-cytotoxic and osteoinductive effects so that these experimental materials can be used clinically for beneficial and preventive purposes.

In 2004, the World Health Organization recommended the development of miniaturized diagnostic devices that are accessible, easy to use, selective, specific, economical, etc. By using nanotechnology to create sensors, the analytical electrochemistry field has made great progress in terms of expanding their application range, improving their reproducibility, decreasing their detection limits, and improving the ease of detection of the analyte of interest. The conductivity of nanocomposites is determined by the concentration, size, and dispersion of nanoparticles in the carbon matrix. The compatibility of carbon materials with different media is generally moderated by their strong interactions and high surface energy. In this paper, we investigated the possibility of obtaining zinc oxide quantum dots (ZnO QDs) for the creation of nanocomposites based on transitional oxides and carbon materials made from reduced graphene oxide (RGO) for electrochemical applications. We used the precipitation process to generate ZnO QDs. The Hummer process was utilized to synthesize RGO. The ZnO-RGO nanocomposites were produced via an ex situ technique. A range of analytical techniques were used to assess the shape, size, structural phase purity, functional groups, wettability, and other characteristics of the samples. Through the use of spectroscopic analysis, the structural aspects of the oxide, carbon material, and composite were investigated. The surface morphology, particle size, and distribution of nanoparticles in the carbon material were examined using a field-emission scanning electron microscope. Goniometric studies followed the percolation and wetting capacity studies of the nanocomposites. The application capacity of the ZnO-RGO nanocomposite was evaluated via cyclic voltammetry.

Acknowledgements:

This work was supported by the Core Program within the National Research Development and Innovation Plan 2022-2027, carried out with the support of MCID, project no. 2307 (µNanoEl).

Knowledge about the strength of restorative materials is crucial to a proper decision-making process on oral rehabilitation. Various test set-ups can determine the strength of materials under different circumstances, however, not much is known about materials’ behavior under higher or more abrupt loads, such as in an impact situation. This study aimed to investigate the effect of different consistencies of resin composite materials (Conventional and Flowable) commonly used for dental restorations on their impact strength. Specimens of two light-cured composites (Flow - Clearfil Majesty ES Flow, Kuraray Noritake; Conv - Clearfil AP-X PLT, Kuraray Noritake) were produced with two different thicknesses (1.0 or 1.5 mm; n=15) to be tested under impact. The impact strength was measured within the Dynstat method. Data were analyzed by one-way ANOVA. The statistical significance was set to p<0.05. The results showed a significant difference between Flow and Conv for 1.0 mm thickness (Flow [11.61±2.66 kJ/m²]; Conv [5.06±0.98 kJ/m²]), but no significant difference was found between materials with 1.5 mm thickness (Flow [6.53±1.04 kJ/m²]; Conv [6.75±1.01 kJ/m²]). Considering thicknesses in the same materials, higher impact strength values were found for the Flow composite with 1.0 mm thickness. This finding can point to a higher population of defects in larger volumes of composite materials. Given the results, it can be concluded that the evaluated flowable resin composite behaved similarly to a regular composite in thicker constructions and that inner defects and residual polymerization shrinkage stresses can make larger pieces more fragile.

Introduction: Magnesium-based metallic alloys have recently gained significant attention in scientific research due to their unique mechanical stability and biodegradability characteristics, making them promising candidates for various applications in tissue engineering, particularly as scaffolds to support cell growth. While magnesium alloys are already employed in clinical settings, such as osteosynthesis screws in hand surgery, previous studies have predominantly focused on their bone-specific biocompatibility, with limited understanding of their interaction with skin and connective tissue. Therefore, the development of functional and biocompatible cell carriers based on magnesium, aimed at promoting skin and connective tissue regeneration, represents a logical next step towards establishing magnesium as a versatile biomaterial.

Methods: Our study aimed to assess the impact of bioabsorbable magnesium alloys, specifically Mg-Y-RE-Zr, on human dermal fibroblasts in vitro. To achieve this objective, we conducted a series of biocompatibility tests following ISO 10993-5 guidelines, encompassing both direct and indirect cell contact scenarios. Key parameters evaluated included cytotoxicity, cell proliferation via XTT, LDH assays, and vital fluorescence staining, along with observations of cell morphology, migration, and colonization under light microscopy. It was particularly noteworthy that the investigation of these cellular responses correlated with the degradation of the metallic material and the development of corrosion products.

Results: Our findings indicate that resorbable magnesium alloys can serve as carrier materials in tissue engineering, interacting positively with human dermal fibroblasts. Notably, a controlled degradation process observed with coated magnesium surfaces demonstrated significant added value in terms of cell-specific biocompatibility compared to rapid degradation.

Conclusion: Our results hold promise for optimizing the design and application of magnesium-based materials in regenerative medicine contexts. They also offer initial insights into the interaction of magnesium alloys with skin and connective tissue, paving the way for a new class of materials in tissue engineering for plastic surgery applications.

Background: In the disciplines of orthopedics and dentistry, acrylic bone cement is frequently utilized for treating bone defects, securing prosthetic implants, remodeling osteoporotic deformities, and repairing fractures. Traditional acrylic bone cement has been found to have several disadvantages, such as prosthesis loosening, heat generation, inferior mechanical characteristics, and weak interface integrity. There was a strong need to improve its qualities; as such, recent research has shown that adding halloysite clay nanotubes (HNTs) to materials based on polymers can enhance their mechanical and thermal qualities. Objectives: We sought to assess the impact of adding 10 weight percent of HNT fillers to traditional acrylic bone cements in order to modify their compressive strength, flexural strength, and exothermic heat generation. Methods: The monomer liquid was combined with acrylic powder to create the control group. The creatively reinforced group was made by combining the acrylic powder with liquid before adding 10 weight percent of HNT fillers. XRF was used to carry out the chemical characterization of the fillers that were used. Measurements were made of the setting temperature, compressive strength, and flexural strength. Independent sample t-tests were used to statistically analyze the data and compare the mean values (p < 0.05). Results: The results showed that when compared to the traditional acrylic bone cement control group, the novel modified acrylic bone cement with 10 weight % HNT fillers had greater mean compressive strength, greater flexural strength, and lower setting temperatures (P≤0.05). Conclusion: It was possible to employ the modified reinforced acrylic bone cement with 10% HNT fillers as an alternative to acrylic bone cement.

Introduction: Prosthodontists must select the restoration design and material to achieve long-lasting oral rehabilitations when restoring endodontically treated teeth. Few studies compare those factors in terms of fit, interfacial volume, and fatigue behavior. Thus, this study aims to evaluate the fatigue behavior, marginal and internal fit, and interfacial volume of CAD-CAM restorations with different designs (endocrowns and crowns) made from different materials (lithium disilicate ceramic, LD, IPS e.max CAD; and resin composite, RC, Tetric CAD).

Methods: Simplified crowns and endocrowns (n= 10) were produced using CAD-CAM technology through scanning by an intraoral scanner (Primescan), followed by milling in a 4-axis machine (CEREC MC XL), and then bonded to fiberglass-reinforced epoxy resin dies. After the restorations' finishing, surface treatment procedures, and bonding, a computed microtomography was used to assess fit and interfacial volume. A cyclic fatigue test (20 Hz, initial load= 100 N/5,000 cycles; step-size= 50 N/10,000 cycles until 1500 N, if specimens survived, the step-size=100 N/10,000 cycles until failure) was performed. Topography and fractography analysis were also performed. Two-way ANOVA and Kaplan-Meier with log-rank (Mantel-Cox) test were run (α= 0.05).

Results: Endocrowns presented a superior axio-occlusal fit, while crowns presented a better cervical-axial and occlusal fit. LD restorations had a superior occlusal fit, while RC had a better marginal fit. The interfacial volume was similar among the tested groups. Fatigue behavior was superior for RC restorations compared to LD ones, independently of the restoration design. LD restorations presented a softer topography compared to RC.

Conclusion: The restoration design affected the cervical-axial, axio-occlusal, and occlusal fit. The marginal gap was similar between designs, but it was impacted by the restorative material, as well as the occlusal fit. The fatigue behavior was not influenced by the restoration design, meanwhile RC restorations showed superior performance compared to LD ones.

In the early stage of transplantation, macrophage cells play an important role in reacting with the transplantation materials. Minimizing the reaction by maintaining the low inflammation of the original decellularized porcine pericardium (dPPC) after the modification process is necessary to avoid rejection. Over the healing process, the fibroblast is the key cell to form the adhesion between the membrane and the wound site. Repelling the fibroblast to adhere to the membrane surface is important to achieve good wound healing and ensure that no adhesion forms. Therefore, we investigated the repose of the fibroblast and THP-1 cells to the multi-arm PEGNHS-modified dPPC.

In this study, dPPC was prepared by the high-hydrostatic-pressure method and confirmed by means of H&E staining and residual DNA quantification. It was then modified with α-succinimidyloxyglutaryl-ω-succinimidyloxyglutaryloxy-polyoxyethylene (2-arm PEGNHS), pentaerythritol tetra (succinimidyloxyglutaryl) polyoxyethylene (4-arm PEGNHS), and hexaglycerol octa(succinimidyloxyglutaryl) polyoxyethylene (8-arm PEGNHS) and confirmed by ATR-FTIR, anti-PEG antibodies, and ninhydrin assay. The modification was carried out over the amine bond between the NH₂ of dPPC and the NHS functional group of PEG with molar ratios of 1:1 and 1:2. The prediction of the inflammation levels and fibroblast repelling in vitro was performed by using THP-1 cells and NIH3T3 cells, respectively.

The dPPC was confirmed by the loss of cellular nuclei and the residual DNA. The modification was confirmed by increasing the C-O-C bond and by the the brown color of the anti-PEG antibodies. The free amine group was significantly reduced after the introduction of the PEG molecules. Among all conditions, 8-arm PEG-modified dPPC in a molar ratio 1:2 was significantly repelling the fibroblasts, and then, cells started to restore on day 7 of culture. The THP-1cells were also repelling and exhitibed a low inflammation secretion level. With these observations, the technology of cell-repelling surfaces was developed and could be used to fabricate anti-adhesion membranes.