Search Results (3)

Silver nanoparticles (AgNPs) are remarkably able to eliminate microorganisms, but induce cytotoxicity in mammalian cells, and zinc oxide nanoparticles (ZnONPs) are considered to have a wide bactericidal effect with weak cytotoxicity. In this study, both zinc oxide nanoparticles and silver nanoparticles were co-synthesized on a nano-silicate platelet (NSP) to prepare a hybrid of AgNP/ZnONP/NSP. Ultraviolet–visible spectroscopy (UV-Vis), X-ray diffraction (XRD), and transmission electron microscopy (TEM) were used to characterize the formation of nanoparticles on the NSP. Synthesized ZnONP/NSP (ZnONP on NSP) was confirmed by the absorption peaks on UV-Vis and XRD. AgNP synthesized on ZnONP/NSP was also characterized by UV-Vis, and ZnONP/NSP showed no interference with synthesis. The images of TEM demonstrated that NSP provides physical support for the growth of nanoparticles and could prevent the inherent aggregation of ZnONP. In antibacterial tests, AgNP/ZnONP/NSP exhibited more efficacy against Staphylococcus aureus (S. aureus) than ZnONP/NSP (ZnONP was synthesized on NSP) and AgNP/NSP (AgNP was synthesized on NSP). In cell culture tests, 1/10/99 (weight ratio) of AgNP/ZnONP/NSP exhibited low cytotoxicity for mammalian cells (>100 ppm). Therefore, AgNP/ZnONP/NSP, containing both AgNP and ZnONP, with both strong antibacterial qualities and low cytotoxicity, showed potentially advantageous medical utilizations due to its antibacterial properties. Full article

The aim of this study was to investigate and compare, radiographically and clinically, the impacts of calcium-silicate based-cement (CSBC), nano-hydroxyapatite and platelet-rich fibrin (PRF) as pulpotomy agents in permanent immature molars with incomplete root development. Sixty-three participants (63 permanent immature molars) were included in this study. The patients were randomly divided into three equal groups. Fast setting MTA (MM-MTA), nano-hydroxyapatite and platelet-rich fibrin were used as pulpotomy agents. The teeth were evaluated clinically and radiographically after 6 and 12 months by two blinded examiners. Apical closure and pulp canal obliteration percentages were recorded. The in vitro reaction of the tested materials after a 7-day immersion period of the different materials in phosphate-buffered solution was analyzed using scanning electron microscopy to associate the in vitro mineralization with in vivo pulp canal obliteration percentages. Data were analyzed using Chi-square and ANOVA tests (α = 0.05). No significant difference was found between the three tested groups in terms of clinical and radiographic success (p > 0.05). All cases demonstrated evidence of root growth, including complete apical closure or continued apical closure. At 12 months, complete apical closure was found among the MM-MTA group (50%), nano-hydroxyapatite group (55%) and platelet-rich fibrin group (60%) (p > 0.05). After 12 months, pulp canal obliteration was more observed in the MM-MTA and nano-hydroxyapatite groups than in the PRF group (p < 0.05). MM-MTA (auto-mixed), NHA (hand-mixed) and PRF (autologous) could be used as pulpotomy agents since they exhibit comparable high clinical and radiographic success rates. However, the fact that the groups managed with MM-MTA and NHA have a higher tendency to canal obliteration might indicate that PRF should be considered the first choice material as pulpotomy agent, as it would make retreatment considerably easier. Full article

Nano-silicate platelets (NSP), an exfoliated product from natural clays, have been validated for biosafety and as an effective supplement to alleviate mycotoxicosis. Since NSP induced noticeable cell death, we therefore investigated further the mechanism of cytotoxicity caused by NSP. Exposure to NSP impaired membrane integrity and caused cell death in a dose-dependent manner. Reactive oxygen species (ROS) generation other than of NADH oxidase origin, and subcellular interactions by internalized NSP also contributed to NSP-induced cell death. NSP persistently provoked receptor-interacting protein 1 Ser/Thr (RIP1) kinase and caspase 6 and 3/7 activation without altering caspase 8 activity and induced evident chromatolysis of necrosis in the later stage. These events proceeded along with increased ER stress and mitochondrial permeability, to final Cyt-C (Cytochrome C) release and AIF (apoptosis inducing factor) translocation, a hallmark of cell necroptosis. Fluorescent probing further manifested NSP traffic, mostly adherence on the cell surfaces, or via internalization, being compartmentalized in the nuclei, cytosols, and mitochondria. Pharmacological approaches with specific inhibitors suggested that endocytosis and particularly RIP1 kinase provocation mediate NSP-induced cell death independent of caspase activation. In conclusion, the necroptotic process contributes to most of the cell death induced by NSP due to membrane interactions/impaired integrity, ROS generation, and subcellular interactions by internalized NSP. Full article