Facilitating safe and sustained submucosal lift through an endoscopically injectable shear-thinning carboxymethyl starch sodium hydrogel.

Traditional submucosal filling materials frequently show insufficient lifting height and duration during clinical procedures. Here, the anionic polysaccharide polymer sodium carboxymethyl starch and cationic Laponite to prepare a hydrogel with excellent shear-thinning ability through physical cross-linking, so that it can achieve continuous improvement of the mucosal cushion through endoscopic injection. The results showed that the hydrogel (56.54 kPa) had a lower injection pressure compared to MucoUp (68.56 kPa). The height of submucosal lifting height produced by hydrogel was higher than MucoUp, and the height maintenance ability after 2 h was 3.20 times that of MucoUp. At the same time, the hydrogel also showed satisfactory degradability and biosafety, completely degrading within 200 h. The hemolysis rate is as low as 0.76 %, and the cell survival rate > 80 %. Subcutaneous implantation experiments confirmed that the hydrogel showed no obvious systemic toxicity. Animal experiments clearly demonstrated the in vivo feasibility of using hydrogels for submucosal uplift. Furthermore, successful endoscopic submucosal dissection was executed on a live pig stomach, affirming the capacity of hydrogel to safely and effectively facilitate submucosal dissection and mitigate adverse events, such as bleeding. These results indicate that shear-thinning hydrogels have a wide range applications as submucosal injection materials.

Thermally-treated asbestos-cement wastes as supplementary precursor for geopolymeric binders: CO2 emission and properties.

This article explores the impact of thermally treated asbestos-cement waste (ACWT) on metakaolin-based geopolymers, using liquid sodium silicate (LSS) and liquid potassium silicate (LKS) as alkali activators. Through statistical mixture design, various formulations were tested for rheological parameters, mineralogical composition, efflorescence mass, electrical conductivity, compressive strength, and CO2 emissions. Formulations with sodium silicate exhibited higher yield stress compared to those with potassium silicate, while flash setting occurred in LKS-activated mixtures with high ACWT content. Alkali activator content significantly affected mechanical strength and leachate electrical conductivity. CO2 emissions were higher for LKS-activated formulations but lower for those with more ACWT. Finally, by incorporating ACWT, it was possible to optimize the formulations, resulting in high compressive strength, reduced free ions, and reduced negative environmental impact.

Development of a tannic acid- and silicate ion-functionalized PVA-starch composite hydrogel for in situ skeletal muscle repairing.

The repair capacity of skeletal muscle is severely diminished in massive skeletal muscle injuries accompanied by inflammation, resulting in muscle function loss and scar tissue formation. In the current work, we developed a tannic acid (TA)- and silicate ion-functionalized tissue adhesive poly(vinyl alcohol) (PVA)-starch composite hydrogel, referred to as PSTS (PVA-starch-TA-SiO32-). It was formed based on the hydrogen bonding of TA to organic polymers, as well as silicate-TA ligand interaction. PSTS could be gelatinized in minutes at room temperature with crosslinked network formation, making it applicable for injection. Further investigations revealed that PSTS had skeletal muscle-comparable conductivity and modulus to act as a temporary platform for muscle repairing. Moreover, PSTS could release TA and silicate ions in situ to inhibit bacterial growth, induce vascularization, and reduce oxidation, paving the way to the possibility of creating a favorable microenvironment for skeletal muscle regeneration and tissue fibrosis control. The in vivo model confirmed that PSTS could enhance muscle fiber regeneration and myotube formation, as well as reduce infection and inflammation risk. These findings thereby implied the great potential of PSTS in the treatment of formidable skeletal muscle injuries.

Crystal scatter effects in a large-area dual-panel Positron Emission Mammography system.

Positron Emission Mammography (PEM) is a valuable molecular imaging technique for breast studies using pharmaceuticals labeled with positron emitters and dual-panel detectors. PEM scanners normally use large scintillation crystals coupled to sensitive photodetectors. Multiple interactions of the 511 keV annihilation photons in the crystals can result in event mispositioning leading to a negative impact in radiopharmaceutical uptake quantification. In this work, we report the study of crystal scatter effects of a large-area dual-panel PEM system designed with either monolithic or pixelated lutetium yttrium orthosilicate (LYSO) crystals using the Monte Carlo simulation platform GATE. The results show that only a relatively small fraction of coincidences (~20%) arise from events where both coincidence photons undergo single interactions (mostly through photoelectric absorption) in the crystals. Most of the coincidences are events where at least one of the annihilation photons undergoes a chain of Compton scatterings: approximately 79% end up in photoelectric absorption while the rest (<1%) escape the detector. Mean positioning errors, calculated as the distance between first hit and energy weighted (assigned) positions of interaction, were 1.70 mm and 1.92 mm for the monolithic and pixelated crystals, respectively. Reconstructed spatial resolution quantification with a miniDerenzo phantom and a list mode iterative reconstruction algorithm shows that, for both crystal types, 2 mm diameter hot rods were resolved, indicating a relatively small effect in spatial resolution. A drastic reduction in peak-to-valley ratios for the same hot-rod diameters was observed, up to a factor of 14 for the monolithic crystals and 7.5 for the pixelated ones.

Dissolved silica affects the bulk iron redox state and recrystallization of minerals generated by photoferrotrophy in a simulated Archean ocean.

Chemical sedimentary deposits called Banded Iron Formations (BIFs) are one of the best surviving records of ancient marine (bio)geochemistry. Many BIF precursor sediments precipitated from ferruginous, silica-rich waters prior to the Great Oxidation Event at ~2.43 Ga. Reconstructing the mineralogy of BIF precursor phases is key to understanding the coevolution of seawater chemistry and early life. Many models of BIF deposition invoke the activity of Fe(II)-oxidizing photoautotrophic bacteria as a mechanism for precipitating mixed-valence Fe(II,III) and/or fully oxidized Fe(III) minerals in the absence of molecular oxygen. Although the identity of phases produced by ancient photoferrotrophs remains debated, laboratory experiments provide a means to explore what their mineral byproducts might have been. Few studies have thoroughly characterized precipitates produced by photoferrotrophs in settings representative of Archean oceans, including investigating how residual Fe(II)aq can affect the mineralogy of expected solid phases. The concentration of dissolved silica (Si) is also an important variable to consider, as silicate species may influence the identity and reactivity of Fe(III)-bearing phases. To address these uncertainties, we cultured Rhodopseudomonas palustris TIE-1 as a photoferrotroph in synthetic Archean seawater with an initial [Fe(II)aq ] of 1 mM and [Si] spanning 0-1.5 mM. Ferrihydrite was the dominant precipitate across all Si concentrations, even with substantial Fe(II) remaining in solution. Consistent with other studies of microbial iron oxidation, no Fe-silicates were observed across the silica gradient, although Si coprecipitated with ferrihydrite via surface adsorption. More crystalline phases such as lepidocrocite and goethite were only detected at low [Si] and are likely products of Fe(II)-catalyzed ferrihydrite transformation. Finally, we observed a substantial fraction of Fe(II) in precipitates, with the proportion of Fe(II) increasing as a function of [Si]. These experimental results suggest that photoferrotrophy in a Fe(II)-buffered ocean may have exported Fe(II,III)-oxide/silica admixtures to BIF sediments, providing a more chemically diverse substrate than previously hypothesized.

Comparison of Marginal Adaptation, Surface Hardness and Bond Strength of Resected and Retrofilled Calcium Silicate-based Cements Used in Endodontic Surgery: An In Vitro Study.

AIMS: This study compared the effects of orthograde and retrograde methods on marginal adaptation, surface hardness, and push-out bond strength (POBS) of three calcium silicate-based used in endodontic surgery. MATERIALS AND METHODS: Ninety single-rooted human mandibular premolars were randomly assigned into six groups (n = 15/group): groups I and II, ProRoot mineral trioxide aggregate (MTA) with orthograde and retrograde methods; groups III and IV, Biodentine (BD) with orthograde and retrograde methods; groups V and VI, iRoot BP Plus (BP-RPM) with orthograde and retrograde methods. After obturation, the apical 3 mm of each root was sectioned into two 1-mm-thick root slices and evaluated for marginal adaptation using a scanning electron microscope, surface hardness using Vickers hardness tester and POBS using a universal testing machine. RESULTS: Orthograde placement had a higher maximum gap width than retrograde placement (p < 0.05), but there was no significant difference among the tested materials (p > 0.05). Biodentine exhibited lower surface hardness than ProRoot MTA and iRoot BP Plus (p < 0.05), but there was no significant difference between ProRoot MTA and iRoot BP Plus (p > 0.05). Orthograde placement had higher POBS compared with retrograde placement (p < 0.05). Biodentine had higher POBS than iRoot BP Plus (p < 0.05), but no significant difference from ProRoot MTA (p > 0.05). The failure mode was mainly mixed for all the tested materials regardless of material type or placement technique. CONCLUSION: The retrograde method had better marginal adaptation; however, the orthograde method provided better dislodgement resistance. Biodentine had lower surface hardness than MTA and iRoot BP Plus with both techniques, whereas iRoot BP Plus demonstrated lower dislodging resistance than BD. CLINICAL SIGNIFICANCE: The current findings suggest that orthograde technique, a simpler periapical surgery, with ProRoot MTA provides potentially better surface hardness and POBS than BD and iRoot BP Plus in single-canal teeth.

Efeito de diferentes irrigantes finais na resistência união de um cimento de silicato de cálcio: estudo in vitro / Effect of different final irrigants on the bond strength of a calcium silicate cement : in vitro study

Objetivo: Este estudo teve como objetivo avaliar a resistência de união do cimento Biodentine® à dentina radicular após a utilização de diferentes irrigantes finais. Método: Vinte dentes humanos extraídos tiveram seu terço médio radicular cortado em fatias que foram submersas em hipoclorito de sódio 2,5% e posteriormente divididas aleatoriamente em 4 grupos experimentais (n=15) conforme o irrigante final utilizado (1) água destilada (controle), (2) QMixTM, (3) ácido cítrico 10%, (4) EDTA 17%. Após a imersão na substância teste as amostras foram preenchidas com o cimento Biodentine e imersas em solução salina tamponada com fosfato (PBS) por um período de 7 dias. O teste de push out foi realizado e os valores de resistência de união em Mpa foram obtidos. Os dados foram analisados pelos testes de Kruskal Wallis e Studend- Newman-Keuls. Resultados: Os piores valores de união foram obtidos após a utilização do EDTA enquanto a água destilada, o QMix e o ácido cítrico apresentaram resultados estatisticamente semelhantes entre si. Conclusão: A remoção da smear layer não resultou em melhora nos resultados de união do cimento Biodentine.(AU)

Objective: This study aimed to evaluate the bond strength of Biodentine® cement to root dentin after the use of different final irrigants. Method: Twenty extracted human teeth had their middle root third cut into slices that were submerged in 2.5% sodium hypochlorite and then randomly divided into 4 experimental groups (n=15) according to the final irrigant used (1) distilled water (control), (2) QMixTM, (3) 10% citric acid, (4) 17% EDTA. After immersion in the test substance the samples were filled with Biodentine cement and immersed in phosphate buffered saline (PBS) for a period of 7 days. The push out test was performed and the bond strength values in MPa were obtained. The data were analyzed by Kruskal Wallis and Studend- Newman-Keuls tests. Results: The worst bond values were obtained after using EDTA while distilled water, QMix and citric acid showed statistically similar results to each other. Conclusion: Removal of the smear layer did not result in improved bonding results of Biodentine cement.(AU)

Root filling quality and bond strength of endodontic sealers to human and bovine dentin / Qualidade da obturação e resistência de união de cimentos endodônticos à dentina humana e bovina

Objetivo: Este estudo teve como objetivo comparar a qualidade da obturação e a resistência de união de dois cimentos endodônticos, AH Plus e Bio-C Sealer, em dentes humanos e bovinos. Métodos: Os canais radiculares de 60 dentes unirradiculares [30 humanos (H) e 30 bovinos (B)] foram preparados e obturados por condensação lateral da guta-percha e AH Plus (grupos AP-H e AP-B) ou Bio-C Sealer (grupos BC-H e BC-B). Seis fatias de 1,5 mm de espessura foram obtidas de cada raiz. Os espécimes foram observados em estereomicroscópio para avaliar a qualidade da obturação, considerando possíveis espaços vazios no material obturador. Posteriormente, as fatias radiculares foram avaliadas em termos de resistência de união por push-out e modo de falha. Os dados foram analisados pelos testes de Mann-Whitney e coeficientes de correlação de Spearman (α=5%). Resultados: A qualidade de obturação fornecida por AP e BC foi semelhante em ambos os substratos de dentina. No entanto, ao comparar dentes humanos e bovinos, os escores de espaços vazios foram maiores nas amostras bovinas, para ambos os cimentos. AP teve maior resistência de união à dentina humana e bovina do que BC. No entanto, não houve diferença significativa na resistência de união entre os substratos dentinários, para ambos os cimentos testados. Além disso, houve uma correlação positiva e moderada entre os valores de resistência de união de dentes humanos e bovinos. O modo de falha misto foi o mais prevalente. Conclusão: AP e BC fornecem qualidade de obturação semelhante, mas o primeiro apresenta maiores valores de resistência de união à dentina humana e bovina. A utilização de dentes bovinos como substitutos de amostras humanas parece ser adequada em estudos relacionados à resistência de união, mas não naqueles que testam a qualidade da obturação endodôntica.(AU)

Objective: This study aimed to compare the filling quality and bond strength of two endodontic sealers, AH Plus and Bio-C Sealer, in human and bovine teeth. Methods: The root canals of 60 [30 human (H) and 30 bovine (B)] single-rooted teeth were prepared and filled by lateral condensation of gutta-percha and AH Plus (groups AP-H and AP-B) or Bio-C Sealer (groups BC-H and BC-B). Six 1.5-mm-thick slices were obtained from each root. The specimens were observed under a stereomicroscope to assess filling quality, considering possible voids within the filling material. Subsequently, root slices were evaluated in terms of push-out bond strength and failure mode. Data were analyzed by Mann-Whitney tests and Spearman correlation coefficients (α=5%). Results: The filling quality provided by AP and BC was similar in both dentin substrates. However, when comparing human and bovine teeth, void scores were greater in the bovine samples, for both sealers. AP had higher bond strength to human and bovine dentin than BC. However, there was no significant difference in bond strength between dentin substrates, for both sealers tested. Also, there was a positive and moderate correlation between the bond strength values of human and bovine teeth. The mixed failure mode was the most prevalent. Conclusion: AP and BC provide similar filling quality, but the first presents higher bond strength values to human and bovine dentin. The use of bovine teeth as substitutes for human samples seems adequate in studies related to bond strength, but not in those testing root canal filling quality.(AU)

Nicotine-magnesium aluminum silicate complexes processed by blending: Characterization for usage as drug carriers in mucoadhesive buccal discs.

Complexation of nicotine (NCT) and magnesium aluminum silicate (MAS) has been formed in the dispersions that required multiple preparation steps. In this study, physical blending was used to produce NCT-MAS complexes. NCT, a free-base liquid state form, was adsorbed onto the MAS granules, where the diffusion and intercalation of NCT molecules into the MAS silicate layers occurred. These processes required a minimum of the 7-d-resting period to reach NCT complete distribution. FTIR, XRD, and 29Si NMR suggest that NCT could interact with MAS via hydrogen bonding, water bridging, and ionic electrostatic force. The 12 % NCT-MAS complexes enabled a sustained release of NCT, after a 2-min burst, in pH 6 phosphate buffer through a particle diffusion-controlled mechanism. Buccal discs formulated with NCT-MAS complexes and sodium alginate (SA) as drug carriers and matrix former could control NCT released through drug diffusion and swelling-controlled mechanisms. NCT release and membrane permeation increased with increasing NCT-MAS complexes or decreasing SA concentration. All NCT-MAS-containing buccal discs exhibited mucoadhesive properties related to the swelling characteristics of SA and MAS. Conclusively, NCT-MAS complexes can be produced through an uncomplicated single-step blending process, and the complexes obtained presented a potential to serve as drug carriers in buccal matrix formulations.

Biocompatibility, bioactive potential, porosity, and interface analysis calcium silicate repair cements in a dentin tube model.

OBJECTIVES: This study is to evaluate biocompatibility, bioactive potential, porosity, and dentin/material interface of Bio-C Repair (BIOC-R), MTA Repair HP (MTAHP), and Intermediate Restorative Material (IRM). MATERIALS AND METHODS: Dentin tubes were implanted into subcutaneous of rats for 7, 15, 30, and 60 days. Thickness of capsules, number of inflammatory cells (ICs), interleukin-6 (IL-6), osteocalcin (OCN), and von Kossa were evaluated. Porosity and material/dentin interface voids were also analyzed. Data were submitted to ANOVA and Tukey's tests (p < 0.05). RESULTS: IRM capsules were thicker and contained greater ICs and IL-6-immunopositive cells at 7 and 15 days. BIOC-R capsules exhibited higher thickness and ICs at 7 days and greater IL-6 at 7 and 15 days than MTAHP (p < 0.05). At 30 and 60 days, no significant difference was observed among the groups. OCN-immunopositive cells, von Kossa-positive, and birefringent structures were observed in BIOC-R and MTAHP. MTAHP exhibited higher porosity and interface voids (p < 0.05). CONCLUSIONS: BIOC-R, MTAHP, and IRM are biocompatible. Bioceramics materials demonstrate bioactive potential. MTAHP presented the highest porosity and presence of voids. CLINICAL RELEVANCE: BIOC-R and MTAHP have adequate biological properties. BIOC-R demonstrated lower porosity and presence of voids, which may represent better sealing for its clinical applications.

Carbon dioxide sequestration of iron ore mining waste under low-reaction condition of a direct mineral carbonation process.

Mining waste that is rich in iron-, calcium- and magnesium-bearing minerals can be a potential feedstock for sequestering CO2 by mineral carbonation. This study highlights the utilization of iron ore mining waste in sequestering CO2 under low-reaction condition of a mineral carbonation process. Alkaline iron mining waste was used as feedstock for aqueous mineral carbonation and was subjected to mineralogical, chemical, and thermal analyses. A carbonation experiment was performed at ambient CO2 pressure, temperature of 80 °C at 1-h exposure time under the influence of pH (8-12) and particle size (< 38-75 µm). The mine waste contains Fe-oxides of magnetite and hematite, Ca-silicates of anorthite and wollastonite and Ca-Mg-silicates of diopside, which corresponds to 72.62% (Fe2O3), 5.82% (CaO), and 2.74% (MgO). Fe and Ca carbonation efficiencies were increased when particle size was reduced to < 38 µm and pH increased to 12. Multi-stage mineral transformation was observed from thermogravimetric analysis between temperature of 30 and 1000 °C. Derivative mass losses of carbonated products were assigned to four stages between 30-150 °C (dehydration), 150-350 °C (iron dehydroxylation), 350-700 °C (Fe carbonate decomposition), and 700-1000 °C (Ca carbonate decomposition). Peaks of mass losses were attributed to ferric iron reduction to magnetite between 662 and 670 °C, siderite decarbonization between 485 and 513 °C, aragonite decarbonization between 753 and 767 °C, and calcite decarbonization between 798 and 943 °C. A 48% higher carbonation rate was observed in carbonated products compared to raw sample. Production of carbonates was evidenced from XRD analysis showing the presence of siderite, aragonite, calcite, and traces of Fe carbonates, and about 33.13-49.81 g CO2/kg of waste has been sequestered from the process. Therefore, it has been shown that iron mining waste can be a feasible feedstock for mineral carbonation in view of waste restoration and CO2 emission reduction.

Biocompatibility and bioactive potential of an experimental tricalcium silicate-based cement in comparison with Bio-C repair and MTA Repair HP materials.

AIM: To evaluate the tissue reaction of a tricalcium silicate-based repair material associated with 30% calcium tungstate (TCS + CaWO4 ) in comparison to Bio-C Repair (Bio-C; Angelus) and to MTA Repair HP (MTA HP; Angelus). METHODOLOGY: Polyethylene tubes filled with one of the materials or left empty (control group, CG) were implanted into the subcutaneous tissues of rats for 7, 15, 30 and 60 days (n = 32/group). The capsule thickness, number of inflammatory cells, collagen content, interleukin-6 (IL-6), osteocalcin (OCN), von Kossa reaction and analysis under polarized light were evaluated. The data were subjected to generalized linear models for repeated measures, except the OCN. OCN data were submitted to Kruskal-Wallis and Dunn's post hoc test and Friedman followed by Nemenyi's test at significance level of 5%. RESULTS: At all time points, significant differences in the number of inflammatory cells were not observed between TCS + CaWO4 and Bio-C, whereas, at 15, 30 and 60 days, no significant difference was detected between TCS + CaWO4 and MTA HP. At all periods, significant differences were not detected in the number of fibroblasts in TCS + CaWO4 versus MTA HP, and, at 60 days, no significant difference was demonstrated between these groups and CG. Significant differences in the immunoexpression of IL-6 were not detected amongst bioceramic materials at all periods. From 7 to 60 days, significant reduction in the number of inflammatory cells, number of IL-6-immunopositive cells and in the capsule thickness was accompanied by significant increase in the collagen in all groups. OCN-immunolabelled cells, von Kossa-positive structures and amorphous calcite deposits were observed around all materials, whereas, in the CG, these structures were not seen. CONCLUSIONS: These findings indicate that the experimental material (TCS + CaWO4 ) is biocompatible and has a bioactive potential, similar to the MTA HP and Bio-C Repair, and suggest its use as a root repair material.

Effects of a mineralization-promoting peptide on the physical and chemical properties of mineral trioxide aggregate.

Mineral trioxide aggregate (MTA) has been used widely in dentistry due to its sealing ability and biocompatibility. Delayed setting time is one of the major limitations of MTA. Various additives have been studied to further improve the properties of MTA with varied degrees of success. In this study, we have investigated the effect of a calcium phosphate mineralization promoting-peptide (MPP3) on the physical and chemical properties of MTA in comparison with Na2HPO4. Based on the reported effects of MPP3 on calcium-phosphate mineralization reaction, our hypothesis was that MPP3 may also show beneficial effects on the calcium-silicate mineralization system of MTA. Na2HPO4 was used for comparison since its setting accelerant effect on MTA has been well documented. The cements were prepared by mixing with distilled water, 0.40 mM MPP3 solution, 15% Na2HPO4 solution, and a combination of MPP3 and Na2HPO4 solution. Initial and final setting times were measured via Vicat needle. Microhardness values were measured via Vickers indenter at 1,3,7, and 28 days after hydration. Compressive strength after setting was measured via universal testing machine. Morphological and compositional analyses were performed via FESEM imaging, XRD and Raman spectroscopy. The microhardness data was evaluated via repeated-measures ANOVA. Setting time and compressive strength data were evasluated via one-way ANOVA. Initial setting time was reduced to ∼3 min in the Na2HPO4 containing groups but remained at ∼5 min in the control and MPP3 groups. Final setting times were significantly reduced in all groups compared to the control group. The reduction in the final setting times in the Na2HPO4 containing groups were significantly higher compared to the MPP3 group. Microhardness was significantly higher in the MPP3 group at all time points. No statistically significant difference in compressive strength was observed among the groups. FESEM analysis showed presence of ettringite crystals in the MPP3 group, and NaBiO3 crystals in the Na2HPO4 containing groups. XRD analysis showed a broadening of peaks at 2θ = 32° in the Na2HPO4 containing groups, possibly due to presence of NaBiO3. Raman spectroscopy showed statistically higher ettringite content in the MPP3 containing groups. Our findings indicate that MPP3 is a beneficial additive to eliminate some of the drawbacks associated with MTA with no detrimental effects on mechanical properties and without resulting in phases that potentially cause discoloration, such as NaBiO3. We propose that the reduced final setting time and increased microhardness by MPP3 may be associated with the increased ettringite content. Future studies, where wider range of MPP3 concentrations are studied may help elucidate and optimize the beneficial effects of MPP3 observed in this study.

A comprehensive in vitro comparison of the biological and physicochemical properties of bioactive root canal sealers.

OBJECTIVES: To evaluate the biological and physicochemical features of bioactive root canal sealers. MATERIALS AND METHODS: Human periodontal ligament fibroblasts (hPDLF) and human osteoblasts (hOB) were exposed to eluates of three bioactive root canal sealers, GuttaFlow® bioseal (GF), BioRoot™ RCS (BR), and TotalFill® BC Sealer (TF), and the epoxy resin-based sealer AH plus® (AH). Cytotoxicity and cellular inflammatory response were evaluated. The osteogenic potential was examined using human mesenchymal stem cells (hMSC). Film thickness, flowability, and pH were assessed. Root canal treatment was performed on human extracted teeth to evaluate the sealers' tightness towards bacterial penetration. The antibacterial activity against common pathogens in primary root canal infections was tested. RESULTS: AH was severely cytotoxic to hPDLF and hOB (p < 0.001). The bioactive sealers were generally less cytotoxic. IL-6 levels in hPDLF were elevated in the presence of AH (p < 0.05). AH and GF suppressed IL-6 production in hOB (p < 0.05). AH and BR stimulated the PGE2 production in hPDLF and hOB (p < 0.05). BR was the only sealer that led to calcium deposits in hMSC (p < 0.05). TF and AH showed the lowest film thickness and the highest flowability. Bacterial tightness was best in teeth filled with AH and BR. All sealers showed similar antimicrobial activity, but the overall antimicrobial efficacy was moderate as the bacteria were reduced by just one log scale (p < 0.05). CONCLUSIONS: This study revealed favorable in vitro results regarding the biocompatibility of the bioactive root canal sealers. CLINICAL RELEVANCE: Bioactive root canal sealers may be a useful alternative to epoxy resin-based sealers.

CO2-assisted 'Weathering' of Steel Slag-Derived Calcium Silicate Hydrate: A Generalized Strategy for Recycling Noble Metals and Constructing SiO2-Based Nanocomposites.

The spent adsorbent loaded by toxic metals is a solid hazardous waste which could cause significant secondary pollution due to potential possible additional release of metal ions. Therefore, the main subject is direct reutilization of spent adsorbents which can further economically and realistically offer new features, like recycling metal adsorbed, or formation of functional SiO2-based nanocomposites. The nanoporous structure and negative surface charges enable steel slag-derived amorphous calcium silicate hydrate (CSH) to retain effectively the incoming metal ions (e. g. Au3+, Ag+, Pd2+, Fe3+, Co2+, Ni2+, Cu2+, Zn2+, Ce3+, Y3+, and Gd3+) by chemisorption. Sparked by natural carbonation 'weathering', which ultimately sequestrates atmospheric CO2 by alkaline silicate minerals to leach calcium from mineral matrix, the decalcification reactions of metal-bearing CSH results in successful recovery of noble metals (Ag, Au, Pd) upon NaOH etching the resultant SiO2 support. Further, SiO2-based heterostructures, containing nanocrystalline metals (e. g. Au0, Ag0, Pd0, Fe0, Co0, Ni0, Cu0, and Zn0) or rare-earth oxides (e. g. CeO2, Y2O3, and Gd2O3), are formed after reduction in H2/Ar (5 vol% H2) flow, which is also very important for the multipurpose immobilization of diverse hybrid materials on SiO2 surface (e. g. Cu0-Ag0@SiO2, Cu0-CeO2@SiO2, and Cu0-Ag0-CeO2@SiO2).

Supercritical carbon dioxide dried double layer laponite XLS and alginate/polyacrylamide construct and immune response.

Fabrication of immunocompatible tissue constructs for bone-cartilage defect regeneration is of prime importance. In this study, a double layer hydrogel was successfully synthesized, where alginate/polyacrylamide were formulated to represent cartilage layer (5-10 % (w/w) total polymer ratio) and laponite XLS (2-5-8% (w/w))/alginate/polyacrylamide formed bone layer. Hydrogels were dried by supercritical CO2 at 100 and 200 bar, 45 °C, 5 g/min CO2 flow rate for 2 h. Constructs were treated with collagen, then cellularized and embedded in cell-laden GelMA to mimic the cellular microenvironment. The optimum weight ratio of alginate/polyacrylamide:laponite XLS was 10:5 based on mechanical strength test results. The constructs yielded high porosity (91.50 m2/g) and mesoporous structure, owing to the diffusivity of CO2 at 200 bar (0.49 × 10-7 m2/s). Constructs were then treated with collagen to increase cell adhesion and ATDC5 cells were seeded in the cartilage layer, whereas hFOB cells to the bone layer. About 10-15 % higher cell viability was attained. The porous structure of the construct allowed infiltration of macrophages, promoted polarization and positively affected the behavior of macrophages, yielding a decrease in M1 markers, whereas an increase in M2 on day 4. The formulated tissue constructs would be of value in tissue engineering applications.

An in vitro assessment of the toxicity of two-dimensional synthetic and natural layered silicates.

Natural Layered Silicates (NLS) and Synthetic Layered Silicates (SLS) are a diverse group of clay minerals that have attracted great interest in various branches of industry. However, despite growing demand for this class of material, their impact on human health has not been fully investigated. Therefore, the aim of this study was to evaluate and compare the potential toxic effects of a wide range of commercially available SLS and NLS of varying physicochemical properties (lithium (Li) or fluoride (F) content and size). Mouse BALB/c monocyte macrophage (J774A.1) and human monocyte-derived macrophages (MDMs) were chosen as in vitro models of alveolar macrophages. Montmorillonite, hectorite, Medium (med) F/High Li and Low F/Med Li particles, were cytotoxic to cells and induced potent pro-inflammatory responses. The remaining particles (No F/Very (V)Low Li, No F/Med Li, No F/Low Li, High F/Med Li and High F/Med Li washed) were non- to relatively low- cytotoxic and inflammogenic, in both type of cells. In an acellular condition none of the tested samples increased reactive oxygen species (ROS), while ROS generation was observed following exposure to sublethal concentrations of Med F/High Li, Low F/Med Li, montmorillonite and hectorite samples, in J774A.1 cells. Based on the results obtained in this study the toxic potency of tested samples was not associated with lithium or fluoride content, but appeared to be dependent on particle size, with the platelets of larger dimension and lower surface area being more potent than the smaller platelet particles with higher surface area. In addition, the increased bioactivity of Med F/High Li and Low F/Med Li was associated with endotoxin contamination. Obtained results demonstrated that layered silicate materials have different toxicological profiles and suggest that toxicological properties of a specific layered silicate should be investigated on an individual basis.

Facile extrusion 3D printing of gelatine methacrylate/Laponite nanocomposite hydrogel with high concentration nanoclay for bone tissue regeneration.

The extrusion 3D printing of hydrogels has evolved as a promising approach that can be applied for specific tissue repair. However, the printing process of hydrogel scaffolds with high shape fidelity is inseparable from the complex crosslinking strategy, which significantly increases the difficulty and complexity of printing. The aim of this study was to develop a printable hydrogel that can extrude at room temperature and print scaffolds with high shape fidelity without any auxiliary crosslinking during the printing process. To this end, a novel formulation consisting of a Laponite suspension with a high solid concentration and a gelatine methacrylate (GelMA) nanocomposite hydrogel was developed. A homogeneously dispersed high-concentration (up to 20% w/v) Laponite suspension was obtained by stirring at 0 °C. The addition of Laponite with high concentration improved the rheological properties, the degradation stability, and the mechanical strength of the hydrogel. The formulation of 15% (w/v) GelMA and 8% (w/v) Laponite nanocomposite hydrogel exhibited desirable printability and biocompatibility. The GelMA/Laponite hydrogels significantly promoted bone marrow mesenchymal stem cell (BMSC) proliferation and osteogenic differentiation. Both desirable printability under mild conditions and cyto-compatibility enable composite hydrogel a potential candidate as biomaterial inks to be applied for bone tissue regeneration.

Fabrication of substituted hydroxyapatite-starch-clay bio-composite coated titanium implant for new bone formation.

The clay/polymeric matrices have much attention from researchers in bio-medical applications due to their numerous uses. This study introduces new orthopedic titanium (Ti) implant with increasing bio-activity by treating the surface of the Ti implant with bio-compatible composite coating. Wollastonite (WST) clay combined minerals (Mg2+and Gd3+) substituted hydroxyapatite (HAP)/Starch composite was prepared using in-situ co-precipitation method. It was successfully coated on the orthopedic grade Ti plate by the Electrophoretic Deposition (EPD) method. The functionality, phase, morphology, and bio-activity analysis of the composite were evaluated by FT-IR, XRD, HR-TEM, and SEM analysis, respectively. The mechanical property, i.e., Vickers microhardness value of the MHAP/Starch/WST composite coated Ti plate, showed 242 ± 1.92 Hv. The in-vitro MG-63 osteoblast cells viability, differentiation, and Ca mineralization of MHAP/Starch/WST composite suggests that this new implant will be used for bone regeneration application after careful evaluation of in-vivo and clinical studies.

NIR-Triggered Blasting Nanovesicles for Targeted Multimodal Image-Guided Synergistic Cancer Photothermal and Chemotherapy.

Escorting therapeutics for malignancies by nano-encapsulation to ameliorate treatment effects and mitigate side effects has been pursued in precision medicine. However, the majority of drug delivery systems suffer from uncontrollable drug release kinetics and thus lead to unsatisfactory triggered-release efficiency along with severe side effects. Herein, we developed a unique nanovesicle delivery system that shows near-infrared (NIR) light-triggered drug release behavior and minimal premature drug release. By co-encapsulation of superparamagnetic iron oxide (SPIO) nanoparticles, the ultrasound contrast agent perfluorohexane (PFH), and cisplatin in a silicate-polyaniline vesicle, we achieved the controllable release of cisplatin in a thermal-responsive manner. Specifically, vaporization of PFH triggered by the heat generated from NIR irradiation imparts high inner vesicle pressure on the nanovesicles, leading to pressure-induced nanovesicle collapse and subsequent cisplatin release. Moreover, the multimodal imaging capability can track tumor engagement of the nanovesicles and assess their therapeutic effects. Due to its precise inherent NIR-triggered drug release, our system shows excellent tumor eradication efficacy and biocompatibility in vivo, empowering it with great prospects for future clinical translation.