Effect of shape of titanium dioxide nanofillers on the properties of dental composites.

The main objective of the present study was to evaluate the effect of the morphology of titanium dioxide nanofillers on the flexural strength and shear bond strength of the dental composite. Spherical and rhombic-shaped nano titanium dioxide fillers were synthesized via solvothermal method and were characterized. Subsequently, these fillers were incorporated into a flowable composite (Filtek™ Z350 XT Flowable Restorative) at 0.5 wt.% and 1.5 wt.% and the prepared specimens were stored in water for 24 h. The specimens were then evaluated for flexural strength using a universal testing machine. Similarly, the shear bond strength of modified composites to the tooth was evaluated and bond failures were analyzed using stereomicroscope magnification. Incorporation of nanofillers significantly enhanced the flexural strength of flowable composite (p = 0.009) with a significant increase at 0.5wt.% of spherical (p = 0.015) and rhomboidal-shaped fillers (p = 0.010). However, no statistically significant difference in flexural strength was observed among the different shapes of nanofillers. The results of our study did not show a significant effect on the shear bond strength of the composites. Thus the reinforcing ability of titanium dioxide nanofillers on dental composite was confirmed in this study, although the effect of using nanofillers with different morphology was not significant.

A Chimeric Cetuximab-Functionalized Corona as a Potent Delivery System for Microtubule-Destabilizing Nanocomplexes to Hepatocellular Carcinoma Cells: A Focus on EGFR and Tubulin Intracellular Dynamics.

In this study, we have developed microtubule destabilizing agents combretastatin A4 (CA4) or 2-methoxyestradiol (2ME) encapsulated poly(d,l-lactide-co-glycolide)-b-poly(ethylene glycol) (PLGA-b-PEG) nanocomplexes for targeted delivery to human hepatocellular carcinoma (HCC) cells. An epidermal growth factor receptor (EGFR) is known to be overexpressed in HCC cells. Therefore, the targeting moiety cetuximab (Cet), an anti-EGFR chimeric monoclonal antibody, is functionalized on the surface of these diblock copolymeric coronas. Cetuximab is associated with the extracellular domain of the EGFR; therefore, the uptake of the cetuximab conjugated nanocomplexes occurred efficiently in EGFR overexpressing HCC cells indicating potent internalization of the complex. The cetuximab targeted-PLGA-b-PEG nanocomplexes encapsulating CA4 or 2ME strongly inhibited phospho-EGFR expression, depolymerized microtubules, produced spindle abnormalities, stalled mitosis, and induced apoptosis in Huh7 cells compared to the free drugs, CA4 or 2ME. Further, the combinatorial strategy of targeted nanocomplexes, Cet-PLGA-b-PEG-CA4 NP and Cet-PLGA-b-PEG-2ME NP, significantly reduced the migration of Huh7 cells, and markedly enhanced the anticancer effects of the microtubule-targeted drugs in Huh7 cells compared to the free drugs, CA4 or 2ME. The results indicated that EGFR receptor-mediated internalization via cetuximab facilitated enhanced uptake of the nanocomplexes leading to potent anticancer efficacy in Huh7 cells. Cetuximab-functionalized PLGA-b-PEG nanocomplexes possess a strong potential for the targeted delivery of CA4 or 2ME in EGFR overexpressed HCC cells, and the strategy may be useful for selectively targeting microtubules in these cells.

Investigation of the hydration process and biological activity of a novel nanosilver incorporated dicalcium silicate based retrograde filling material.

Background: Although several materials have been used for retrograde filling following apical surgeries, there is no consensus on a single best material. Tricalcium silicate-based types of cement have been developed as root-end filling materials mainly due to tricalcium silicate's hydraulic properties. However, its unfavorable setting characteristics and minimal antimicrobial properties have necessitated the introduction of new additives into the existing commercially available materials. To design an affordable product based on a dicalcium silicate with a shorter set time, minimal cytotoxic complications, and enhanced antibacterial activity, we developed a new endodontic cement from pure raw materials, intending to satisfy the prerequisites of ideal retrograde material. Methods: The composition of the experimental calcium silicate-based cement included the addition of calcium chloride and silver nanoparticles in varying concentrations. Structural characterization was carried out using energy dispersive analysis by X-rays using scanning electron microscope (EDAX SEM) and hydration characteristics were performed using an X-ray diffractometer (XRD). The experimental material was further evaluated for biocompatibility using MTT ([3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide)assay and antibacterial activity was evaluated using an agar diffusion test against Enterococcus faecalis. Results: The structural characterization and hydration characteristics revealed that the experimental cement was dicalcium silicate based with favorable biocompatibility and enhanced antibacterial activity. Tricalcium silicate based mineral trioxide aggregate (MTA) also had favourable biocompatibility, however, its antibacterial activity was significantly decreased when compared to the novel cement. Conclusion: All hydraulic cements that are available in the dental market are predominantly tricalcium silicate-based materials. There has been no evidence in the literature to date wherein it has been explored whether a dicalcium silicate-based hydraulic cement can solely be used in root-end cavities. The findings of the study revealed a dicalcium silicate based retrograde filling material with favourable biocompatibility exhibited immediately as well as in the set samples. Incorporation of silver nanoparticles boosted the antibacterial activity when compared to that of ProRoot MTA. This material could potentially reinstate the usual hype created with tricalcium silicate types of cement since dicalcium silicate cements also exhibit similar properties.

Antihepatoma activity of multifunctional polymeric nanoparticles via inhibition of microtubules and tyrosine kinases.

Aim: Synthesis of poly-L-lactic acid nanoparticles comprising of microtubule-inhibitor docetaxel and tyrosine kinase inhibitor sorafenib (PLDS NPs) for hepatoma treatment. Materials & methods: PLDS NPs were prepared by the emulsion solvent evaporation method and the anticancer activity was evaluated in Huh7 hepatoma cells. Results: Real-time imaging of quantum dots incorporating poly-L-lactic acid nanoparticles showed a rapid internalization of the nanoparticles in Huh7 cells. PLDS NPs exerted stronger antiproliferative, apoptotic and antiangiogenic effects than free single drug counterparts. They strongly promoted microtubule bundling, multinucleation and increased mitotic index in Huh7 cells. They also inhibited the expression of pERK1/2, pAKT and cyclin D1. Conclusion: We developed a single-nanoscale platform for dual drug delivery and high-sensitivity quantum dots imaging for hepatoma treatment. [Formula: see text].