In vitro Evaluation of the Cytotoxicity of Different Root Canal Filling Materials

Objective: Aim of the present study was to evaluate the cytotoxicity of Real Seal 1 compared to other commercially available endodontic filling materials: Real Seal (SybronEndo, Orange, CA, USA) and Thermafil (Tulsa Dental, Tulsa, OK, USA). Material and Methods: Periodontal ligament cells from healthy patients were cultured. The eluate of Real Seal 1TM (RS1), Real Seal (RS) and Thermafil (TF) samples was used for the cells viability tests, both diluted (50%) or undiluted (100%). Incubation of the specimens was performed in culture medium for 24 h, 48 h and 72 h at 37 °C under sterile conditions. The cellular mortality was evaluated by MTT test. Results were statistically analysed and the statistical significance was set at p< 0.05. Results: None of the studied materials showed toxic effects during the period of observation (0 -72 h) when compared to the control group. Only RS induced a very modest increase in cell mortality (about 3% at both concentrations used, during the first 24 hours), when increasing the incubation time, however, only the lower concentration continued to show modest toxicity. Conclusions: Results of the present study showed that all tested materials did not exhibit cytotoxic effects when compared to the control group. © Gambarini et al

Biocompatibility of Orthodontic Resins: In vitro Evaluation of Monomer Leaching and Cytotoxic Effects

The aim of this study was to investigate the effect of orthodontic resins on cell survival and to evaluate monomer leaching both before and after resin polymerization. Materials and methods: 3T3 mouse fibroblasts were exposed to three cured and uncured orthodontic resins. Cellular viability was assessed by Alamar Blue assay after 24, 48 and 72 h. High Performance Liquid Chromatography was used to measure the amount of monomers released by the tested samples. Data were analyzed by means of ANOVA and Tukey's test (p<0.05). All tested materials exerted a cytotoxic response. Cytotoxicity tests showed that the uncured samples were more cytotoxic than the polymerized ones. A time-dependent reduction in cellular viability was found. Monomer release analyses indicated a higher elution of Triethylene Glycol Dimethacrylate (TEGDMA) compared to Bisphenol A Glycidyl Methacrylate. TEGDMA release was higher in the uncured samples and showed a time-dependent pattern. Our results showed the role of resin curing in determining the cytotoxic effect of orthodontic resins and suggested that the differences in the chemical composition of resin matrix appeared to be much more related to the decrease in cell viability than the amount of monomer leaching from orthodontic resins. Clinicians should pay greater attention to resin curing after bracket placement in order to reduce the potentially dangerous effect of monomer release

Cinnamaldehyde Loaded poly(lactide-co-glycolide) (PLGA) Microparticles for Antifungal Delivery Application against Resistant Candida albicans and Candida glabrata

Researchers have explored natural products to combat the antibiotic resistance of various microorganisms. Cinnamaldehyde (CIN), a major component of cinnamon essential oil (CC-EO), has been found to effectively inhibit the growth of bacteria, fungi, and mildew, as well as their production of toxins. Therefore, this study aimed to create a delivery system for CIN using PLGA microparticles (CIN-MPs), and to compare the antifungal activity of the carried and free CIN, particularly against antibiotic-resistant strains of Candida spp. The first part of the study focused on synthesizing and characterizing the PLGA MPs, which had no toxic effects in vivo and produced results in line with the existing literature. The subsequent experiments analyzed the antifungal effects of MPs-CIN on Candida albicans and Candida glabrata, both resistant (R) and sensitive (S) strains and compared its efficacy with the conventional addition of free CIN to the culture medium. The results indicated that conveyed CIN increased the antifungal effects of the product, particularly towards C. albicans R. The slow and prolonged release of CIN from the PLGA MPs ensured a constant and uniform concentration of the active principle within the cell

Effects of dental methacrylates on oxygen consumption and redox status of human pulp cells

Several studies have already demonstrated that the incomplete polymerization of resin based dental materials causes the release of monomers which might affect cell metabolism. The aim of this study was to investigate the effects of triethylenglycol-dimethacrylate, 1,4-butanediol-dimethacrylate, urethane-dimethacrylate and 2-hydroxyethyl-methacrylate on 1) cellular energy metabolism, evaluating oxygen consumption rate, glucose consumption, glucose 6-phosphate dehydrogenase activity, and lactate production 2) cellular redox status, through the evaluation of glutathione concentration and of the activities of enzymes regulating glutathione metabolism. Methods: Human pulp cells were used and oxygen consumption was measured by means of a Clark electrode. Moreover, reactive oxygen species production was quantified. Enzymatic activity, glucose and lactate concentrations were determined through a specific kit. Results: triethylenglycol-dimethacrylate, 1,4-butanediol-dimethacrylate and 2-hydroxyethyl-methacrylate induced a decrease in oxygen consumption rate, an enhancement of glucose consumption and lactate production, whilst glucose 6-phosphate dehydrogenase and glutathione reductase activity were not significantly modified. Moreover, the monomers induced an increase of reactive oxygen species production with a consequent increase of superoxide dismutase and catalase enzymatic activities. A depletion of both reduced and total glutathione was also observed. Conclusion: The obtained results indicate that dental monomers might alter energy 44 metabolism and glutathione redox balance in human pulp cell

Recent advances in the label-free characterization of exosomes for cancer liquid biopsy: From scattering and spectroscopy to nanoindentation and nanodevices

Exosomes (EXOs) are nano-sized vesicles secreted by most cell types. They are abundant in bio-fluids and harbor specific molecular constituents from their parental cells. Due to these characteristics, EXOs have a great potential in cancer diagnostics for liquid biopsy and personalized medicine. Despite this unique potential, EXOs are not yet widely applied in clinical settings, with two main factors hindering their translational process in diagnostics. Firstly, conventional extraction methods are time-consuming, require large sample volumes and expensive equipment, and often do not provide high-purity samples. Secondly, characterization methods have some limitations, because they are often qualitative, need extensive labeling or complex sampling procedures that can induce artifacts. In this context, novel label-free approaches are rapidly emerging, and are holding potential to revolutionize EXO diagnostics. These methods include the use of nanodevices for EXO purification, and vibrational spectroscopies, scattering, and nanoindentation for characterization. In this progress report, we summarize recent key advances in label-free techniques for EXO purification and characterization. We point out that these methods contribute to reducing costs and processing times, provide complementary information compared to the conventional characterization techniques, and enhance flexibility, thus favoring the discovery of novel and unexplored EXO-based biomarkers. In this process, the impact of nanotechnology is systematically highlighted, showing how the effectiveness of these techniques can be enhanced using nanomaterials, such as plasmonic nanoparticles and nanostructured surfaces, which enable the exploitation of advanced physical phenomena occurring at the nanoscale level

Controlled Release of 18-β-Glycyrrhetinic Acid from Core-Shell Nanoparticles: Effects on Cytotoxicity and Intracellular Concentration in HepG2 Cell Line

18β-glycyrrhetinic acid (GA) is a pentacyclic triterpene with promising hepatoprotective and anti-Hepatocellular carcinoma effects. GA low water solubility however reduces its biodistribution and bioavailability, limiting its applications in biomedicine. In this work we used core-shell NPs made of PolyD-L-lactide-co-glycolide (PLGA) coated with chitosan (CS), prepared through an osmosis-based methodology, to efficiently entrap GA. NPs morphology was investigated with SEM and TEM and their GA payload was evaluated with a spectrophotometric method. GA-loaded NPs were administered to HepG2 cells and their efficiency in reducing cell viability was compared with that induced by the free drug in in vitro tests. Cell viability was evaluated by the MTT assay, as well as with Electric Cells-Substrate Impedance Sensing (ECIS), that provided a real-time continuous monitoring. It was possible to correlate the toxic effect of the different forms of GA with the bioavailability of the drug, evidencing the importance of real-time tests for studying the effects of bioactive substances on cell cultures

The Challenges of Drug Delivery Systems for Topical Treatments of Local Oral Diseases

The oral mucosa can be affected by numerous local and systemic pathologies [1,2]. To date, most of the topical treatments for local oral disorders are usually based on formulations developed for dermatologic use; consequently, a non-optimal patient compliance may be present because these formulations have a viscid consistency or a bad taste. Moreover, saliva quickly removes the drug from the site of application, reducing its therapeutic efficacy [3-6]. For these reasons, the research of innovative drug delivery systems expressly developed for oral cavity is currently ongoing, with the aim to overcome the above reported obstacles. To solve the problem due to the saliva presence, various possibilities are currently under observation. In particular, it is possible to use hydrogels, able to adhere to mucosa by hydrogen bonds, increasing the permanency of the drug in the oral cavity [7]. Moreover, the active principle, could be administered entrapped inside nanoparticles (NPs) dispersed in the hydrogels [7]. NPs with muco-adhesive properties have been tested to deliver bactericides directly in the oral cavity [8]; interesting results were obtained using NPs constituted by polyethylenimine and dextran sulfate [9], these polymers are able to interact with oral mucosa thanks to ionic bonds formation between the positive NPs and the negative mucosal surface. This type of drug delivery system are very promising but many other studies are necessary, also to evaluate their cytotoxicity and biocompatibility. Surely, topical treatment of oral cancers is one of the most important challenges, especially for the side effects of many chemotherapeutics. A critical aspect in the drug delivery is the need to deliver the active compounds directly into cancer cells at therapeutic concentrations. Many systems are currently under evaluation (i.e. liposomes, viral vectors, polymeric nanoparticles, dendrimers, polymersomes etc. [10,11] and, probably, in the future more systems \u2013 based as nanoparticles - will be available for local drug delivery [12]

BIOSYNTHESIS, CHARACTERIZATION AND BIOMEDICAL APPLICATIONS OF PEPTIDE-BASED HYDROGELS

In recent years, scientific as well as technological interest in the synthesis of peptide-based hydrogel materials have grown dramatically. Applications of such materials are mostly related to the biomedical field, thanks to their biocompatibility and biodegradability. As it is well known, the solid component of a hydrogel can consist of a polymeric network or a supramolecular structure derived from the self-assembly of oligomers or non-polymeric molecules. The ability to control the assembly of such structures by the application of an external stimulus is extremely valuable. Enzyme-catalyzed reactions can be used as selective biological stimuli to trigger hydrogel assembly. In fact, the use of enzymes for the fabrication of peptide-based hydrogels has become an emerging area of scientific research. Recently, we reported the possibility of using microbial lipases to catalyze the synthesis in water of self-assembling peptides. We employed different lipases to efficiently catalyze peptidic bond formation between F-moc phenylalanine and diphenylalanine in aqueous medium. Such biocatalysts were able to synthesize the reaction product F-moc triphenylalanine, with yields ranging from 15 to 33%. The reaction products (Fmoc peptides) spontaneously self-assembled in water to form fibrils, that became entangled to form a three-dimensional structure of fibers with a diameter of approximately 7 nm, as evidenced by AFM measurements. Macroscopically, a stable, self-supporting hydrogel material was produced. Moreover, the influence of the chirality of the aminoacidic moieties on the structure and properties of the hydrogels was investigated. In fact, D aminoacids are interesting building blocks for biomedical applications as they are more stable in vivo. The viscoelastic properties of the synthesized hydrogels were investigated and their biocompatibility with different mammalian cells was assessed. Such hydrogel materials were used to entrap nanostructured drug delivery systems, with the aim of creating a biomaterial that may support cell growth and differentiation of human gingival fibroblasts (HGFs). The release kinetics of dexamethasone (DXM) from biopolymeric nanoparticles entrapped within the hydrogel was studied, confirming the possibility of using such system for the sustained release of a bioactive molecule that is able to promote HGFs differentiation into osteoblasts. Our results suggest the possibility of using F-moc oligopetides as building blocks for a new class of injectable cell scaffolds that could play an important role in bone regeneration, i.e. to reconstruct anatomical defects caused by cancer surgery, malformations and trauma

In vitro Evaluation of the Cytotoxicity of Different Root Canal Filling Materials

Abstract OBJECTIVE: Aim of the present study was to evaluate the cytotoxicity of Real Seal 1 compared to other commercially available endodontic filling materials: Real Seal (SybronEndo, Orange, CA, USA) and Thermafil (Tulsa Dental, Tulsa, OK, USA). MATERIAL AND METHODS: Periodontal ligament cells from healthy patients were cultured. The eluate of Real Seal 1(TM) (RS1), Real Seal (RS) and Thermafil (TF) samples was used for the cells viability tests, both diluted (50%) or undiluted (100%). Incubation of the specimens was performed in culture medium for 24 h, 48 h and 72 h at 37 \ub0C under sterile conditions. The cellular mortality was evaluated by MTT test. Results were statistically analysed and the statistical significance was set at p< 0.05. RESULTS: None of the studied materials showed toxic effects during the period of observation (0 -72 h) when compared to the control group. Only RS induced a very modest increase in cell mortality (about 3% at both concentrations used, during the first 24 hours), when increasing the incubation time, however, only the lower concentration continued to show modest toxicity. CONCLUSIONS: Results of the present study showed that all tested materials did not exhibit cytotoxic effects when compared to the control grou