Investigating the effectiveness of iron nanoparticles synthesized by green synthesis method in chemoradiotherapy of colon cancer.

Current methods of colon cancer treatment, especially chemotherapy, require new treatment methods due to adverse side effects. One important area of interest in recent years is the use of nanoparticles as drug delivery vehicles since several studies have revealed that they can improve the target specificity of the treatment thus lowering the dosage of the drugs while preserving the effectiveness of the treatment thus reducing the side effects. The use of traditional medicine has also been a favorite topic of interest in recent years in medical research, especially cancer research. In this research work, the green synthesis of Fe nanoparticles was carried out using Mentha spicata extract and the synthesized nanoparticles were identified using FT-IR, XRD, FE-SEM and EDS techniques. Then the effect of Mentha spicata, Fe nanoparticles, and Mentha spicata -loaded Fe nanoparticles on LS174t colon cancer cells, and our result concluded that all three, especially Mentha spicata -loaded Fe nanoparticles, have great cytotoxic effects against LS174t cells, and exposure to radiotherapy just further intensified these results. The in vitro condition revealed alterations in the expression of pro-apoptotic BAX and anti-apoptotic Bcl2, suggesting a pro-apoptotic effect from all three components, particularly the Mentha spicata-loaded Fe nanoparticles. After further clinical trials, these nanoparticles can be used to treat colon cancer.

Antimicrobial and Mechanical Properties of Orthodontic Acrylic Resin Containing Zinc Oxide and Titanium Dioxide Nanoparticles Supported on 4A Zeolite.

Polymethyl methacrylate (PMMA) is widely used to manufacture removable orthodontic appliances. However, since the porous structure, cold-curing acrylic resins are susceptible to bacterial adhesion and colonization. The aim of this study was to investigate the antibacterial and mechanical properties of a cold-curing PMMA resin containing ZnO and TiO2 nanoparticles supported on the 4A zeolite. ZnO and TiO2 nanoparticles supported on the 4A zeolite were synthesized. Nanoparticles were added in three compositions as ZnO/4A, TiO2/4A, and ZnO/TiO2/4A at 2wt% and 4wt% concentrations to cold-curing acrylic resin powder (SR Triplex® Cold Ivoclar Vivadent AG, FL-9494 Schaan/Liechtenstein). X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FE-SEM), energy dispersive X-ray (EDX), transmission electron microscopy (TEM), and dynamic light scattering (DLS) were performed to investigate the nanocomposite characteristics. A direct test method was used to assess the antibacterial properties against Streptococcus mutans, Klebsiella pneumoniae, and Escherichia coli. The surface roughness of acrylic samples was measured with a profilometer. Flexural strength was evaluated by a three-point bending test, and one-way ANOVA and Tukey's post hoc tests were used for statistical evaluation of the data. A p value of less than 0.05 was considered statistically significant. XRD confirmed the accurate crystalline structure of synthesized nanoparticles; FE-SEM images showed nanoparticle dispersion within polymerized acryl. The addition of 2 and 4 wt% of ZnO/4A, TiO2/4A, and ZnO/TiO2/4A caused colony reduction in all types of tested microorganisms more than 99% and 100%, respectively. The mean flexural strengths of acrylic specimens containing 2wt% and 4wt% of synthesized nanoparticles were significantly lower than those of the resin without nanoparticles. Fabricated samples showed favorable antibacterial properties but decreased flexural strength.

PEGylated Magnetite/Hydroxyapatite: A Green Nanocomposite for T2-Weighted MRI and Curcumin Carrying.

Background: The design of new magnetic resonance imaging (MRI) contrast media with chemotherapy drug-carrying capacity has an important role in diagnostic and therapeutic purposes. This study aimed to synthesize a polyethylene glycol (PEG)-coated magnetite/hydroxyapatite nanocomposite as an MRI contrast agent investigate its curcumin loading/release properties and consider the cytotoxicity effect of the curcumin-loaded nanocomposite on different cell lines. Materials and Methods: PEGylated magnetite/hydroxyapatite (PMHA) nanocomposite was synthesized and characterized using X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, vibrating sample magnetometry, and energy dispersive X-ray analysis. MTT assay was performed to consider the A549, MCF-7, and MRC-5 cells toxicity of the PMHA and the curcumin-loaded nanocomposite. The r2 relaxivity of the nanocomposite was determined by an MRI device. The curcumin loading and its release from the nanocomposite at pH of 7.4 and 5.5 were investigated. Results: The spherical nanocomposite showed an average size of 20 nm and a superparamagnetic property. PMHA nanocomposite was highly cytocompatible, while the curcumin-loaded nanocomposite showed significant cytotoxicity for A549 and a much higher toxic effect on MCF-7 cancer cells. The r2 relaxivity was measured as 120 mM-1S-1. The curcumin loading capacity of PMHA was 1.9 mg/g, and the curcumin release profile showed a pH-dependent sustained release of the anti-cancer drug that was higher for pH of 5.5. Conclusion: The high r2 relaxivity of PMHA nanocomposite and sustained release of curcumin from the loaded one at the pH of tumor environment suggest that the nanocomposite is a potential candidate for T2-weighted MRI and cancer treatment.

Towards Induction of Angiogenesis in Dental Pulp Stem Cells Using Chitosan-Based Hydrogels Releasing Basic Fibroblast Growth Factor.

INTRODUCTION: Chitosan is a natural biopolymer that attracted enormous attention in biomedical fields. The main components of regenerative endodontic procedures (REPs), as well as tissue engineering, are scaffolds, stem cells, and growth factors. As one of the basic factors in the REPs is maintaining vascularization, this study was aimed at developing basic fibroblast growth factor- (bFGF-) loaded scaffolds and investigating their effects on the angiogenic induction in human dental pulp stem cells (hDPSCs). METHODS: Poly (ε-caprolactone) (PCL)/chitosan- (CS-) based highly porous scaffold (PCL/CS) was prepared and evaluated by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) analyses. The adhesion and survival potency of seeded cells were assessed by SEM and MTT assays, respectively. The amount of angiogenic markers was investigated in gene and protein levels by real-time PCR and western blotting assays, respectively. RESULTS: Based on our findings, the SEM and FTIR tests confirmed the appropriate structure of synthesized scaffolds. Besides, the adhesion and survival rate of cells and the levels of VEGFR-2, Tie2, and Angiopoietin-1 genes were increased significantly in the PCL/CS/bFGF group. Also, the western blotting results showed the upregulation of these markers at protein levels, which were considerably higher at the PCL/CS/bFGF group (P < 0.05). CONCLUSIONS: On a more general note, this study demonstrates that the bFGF-loaded PCL/CS scaffolds have the potential to promote angiogenesis of hDPSCs, which could provide vitality of dentin-pulp complex as the initial required factor for regenerative endodontic procedures.

Comparison of the toxicity of pure and samarium-doped zinc oxide nanoparticles to the green microalga Chlorella vulgaris.

Although doping of various rare earth elements such as samarium on zinc oxide nanoparticles (ZnO NPs) can noticeably improve their photocatalytic performance, it may enhance their toxicity to living organisms. Thus, the toxic impacts of samarium-doped ZnO NPs (Sm/ZnO NPs) on different organisms should be carefully evaluated. In this study, an eco-toxicological experimentation system using the green microalga Chlorella vulgaris was established to determine the potential toxicity of ZnO and Sm/ZnO NPs synthesized by polymer pyrolysis method. Accordingly, growth parameters, oxidative stress biomarkers, and morphological features of the algal cells were analyzed. Both ZnO and Sm/ZnO NPs induced a concentration-dependent cytotoxicity by reducing the cell growth, decreasing photosynthetic pigment contents, and causing deformation in the cellular morphology. Moreover, generation of excessive H2O2, increased activity of superoxide dismutase and ascorbate peroxidase, and reduction in total phenolic and flavonoid contents were observed. Catalase activity was inversely influenced by the NPs in a way that its activity significantly increased at the concentrations of 20 and 25 mg L-1 of ZnO NPs, but was lessened by all supplemented dosages (5-25 mg L-1) of Sm/ZnO NPs. Altogether, the obtained results revealed that Sm-doping can play a significant role in ZnO NP-induced toxicity on C. vulgaris cells.

A Novel Developed Bioactive Composite Resin Containing Silver/Zinc Oxide (Ag/ZnO) Nanoparticles as an Antimicrobial Material against Streptococcus mutans, Lactobacillus, and Candida albicans.

AIM: The objectives of this study were to develop a new bioactive composite resin containing silver/zinc oxide (Ag/ZnO) nanoparticles and investigate the effects on mechanical, cytotoxic, biocompatibility, and antimicrobial properties. MATERIALS AND METHODS: Disc-shaped specimens were prepared from composite with and without nanoparticles in separate culture media containing Streptococcus mutans, Lactobacillus, and Candida albicans. Bracket bonding evaluation was performed on composite without nanoparticles (O), composite containing ZnO (Z) nanoparticles, composite containing ZnO nanoparticles and silver ions (A&Z), and composite containing Ag/ZnO nanoparticles (AZ) synthesized using optical precipitation. RESULTS: Composite resin with nanoparticles (AZ, A&Z, and Z) showed significant antimicrobial properties (P < 0.05). The mean shear bond strength of A&Z composite resin (13.61 ± 0.73 MPa) was significantly less than that of conventional composite resin (19.03 ± 4.12 MPa) (P < 0.05). In addition, the mean shear bond strength of AZ composite resin (20.49 ± 1.03 MPa) was significantly higher than that of Z (16.35 ± 1.03 MPa) and A&Z composite resins. CONCLUSIONS: Incorporation of ZnO nanoparticles and their compounds into orthodontic composite resins induced antibacterial properties against oral pathogens, and of all these nanoparticles, the AZ group exhibited the best antimicrobial activity and highest shear bond strength.

Influence of Physical Dimension and Morphological-Dependent Antibacterial Characteristics of ZnO Nanoparticles Coated on Orthodontic NiTi Wires.

White spot lesions (WSLs) are one of the adverse effects of fixed orthodontic treatments. They are the primary sign of caries, which means inhibiting this process by antibacterial agents will reverse the procedure. The current study tested the surface modification of nickel-titanium (NiTi) wires with ZnO nanoparticles (NPs), as antimicrobial agents. As the morphology of NPs is one of the most critical factors for their properties, the antibacterial properties of different morphologies of ZnO nanostructures coated on the NiTi wire were investigated. For the preparation of ZnO nanostructures, five coating methods, including chemical vapor deposition (CVD), chemical precipitation method, polymer composite coating, sol-gel synthesis, and electrospinning process, were used. The antibacterial activity of NPs was assessed against Streptococcus mutans by the colony counting method. The obtained results showed that all the samples had antibacterial effects. The antibacterial properties of ZnO NPs were significantly improved when the specific surface area of particles increased, by the ZnO nanocrystals prepared via the CVD coating method.

Bioactive chitosan biguanidine-based injectable hydrogels as a novel BMP-2 and VEGF carrier for osteogenesis of dental pulp stem cells.

Nowadays, vascularization and mineralization of bone defects is the main bottleneck in the bone regeneration field that is needed to be overcome and developed. Here, we prepared novel in-situ formed injectable hydrogels based on chitosan biguanidine and carboxymethylcellulose loaded with vascular endothelial growth factor (VEGF) and recombinant Bone morphogenetic protein 2 (BMP-2) and studied its influence on osteoblastic differentiation of dental pulp stem cells (DPSCs). The sequential release behavior of the VEGF and BMP-2 from hydrogels adjusted with the pattern of normal human bone growth. MTT assay exhibited that these hydrogels were non-toxic and significantly increased DPSCs proliferation. The Real-time PCR and Western blot analysis on CG11/BMP2-VEGF showed significantly higher gene and protein expression of ALP, COL1α1, and OCN. These results were confirmed by mineralization assay by Alizarin Red staining and Alkaline phosphatase enzyme activity. Based on these evaluations, these hydrogel holds potential as an injectable bone tissue engineering platform.

Nanocomposite films consisting of functional nanoparticles (TiO2 and ZnO) embedded in 4A-Zeolite and mixed polymer matrices (gelatin and polyvinyl alcohol).

In this study, nanocomposite films with enhanced functional properties were prepared by loading titanium dioxide (TiO2) and/or zinc oxide (ZnO) nanoparticles within 4A zeolite (4AZ) particles, and then incorporating these nanocomposites into a poly (vinyl alcohol) (PVA) and gelatin matrix. The composition and morphology of the films were characterized using atomic force microscopy (AFM), scanning electron microscopy (SEM), Fourier transform infrared (FTIR), and X-ray diffraction (XRD). The thermal behavior of the films was established using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). SEM showed the nanoparticles were dispersed throughout the films when used at these levels. FTIR indicated that the inorganic nanoparticles interacted with the PVA/gelatin polymer network through hydrogen bonding. XRD confirmed that the nanoparticles were in a crystalline state within the films. DSC and TGA showed that introduction of the nanoparticles modified the nanocomposite's thermal behavior. Nanoparticle addition had a number of effects: (i) it decreased film transparency from 78.7% to 69.4% 72.0% and 69.7%; (ii) it decreased film water vapor permeability (WVP) from 8.20 × 10-9 to 5.13 × 10-9, 5.71 × 10-9 and 5.24 × 10-9 g/Pa.h.m; (iii) it reduced film oxygen permeability from 4.57 to 3.29, 3.10 and 3.00 mEq/g; and (i) it increased film tensile strength (TS) from 14.6 to 22.0, 20.3 and 18.0 MPa, for PVA/gelatin films containing 0%, 1.5% ZnO, 1.5% TiO2 and 1% (ZnO + TiO2) nanoparticles, respectively (with the nanoparticles being trapped within 4AZ). Moreover, active nanocomposite films exhibited significant antimicrobial effects especially against gram-negative bacteria. Overall, our results show that nanoparticle-loaded PVA/gelatin nanocomposites may be useful as active biodegradable nanocomposite films for application in the packaging industry and that their properties can be modulated by controlling the nature and level of nanoparticles incorporated.

Effect of Ag-doping on cytotoxicity of SnO2 nanoparticles in tobacco cell cultures.

SnO2 nanoparticles (NPs) are promising materials for electrochemical, catalytic, and biomedical applications due to their high photosensitivity, suitable stability characteristics, wide band gap energy potential, and low cost. Doping SnO2 NPs with metallic elements such as Ag has been used to improve their efficiency. Despite their commercial importance, the current literature lacks investigations to determine their toxic effects on plant systems. In this study, SnO2 and Ag/SnO2 NPs were synthesized using polymer pyrolysis method and characterized by means of XRD, TEM, SEM, EDX, and DLS techniques. Subsequently, the toxicity of the synthesized NPs on cell viability, cell proliferation, and a number of oxidative stress markers were measured in tobacco cell cultures. SnO2 and Ag/SnO2 NPs were found to be polygonal in shape with the size range of 10-30 nm. Both NPs induced cytotoxicity by reducing the cell viability and cell proliferation in a dose-dependent manner. Furthermore, the generation of H2O2, phenolics, flavonoids, and increased activities of superoxide dismutase (SOD) and peroxidase (POD) were observed. According to the results, Ag-doping played a key role in the induction of toxicity in tobacco cell cultures. The obtained results confirmed that SnO2 and Ag/SnO2 NPs induced cytotoxicity in tobacco cells through oxidative stress.

Antimicrobial activity of Titanium dioxide and Zinc oxide nanoparticles supported in 4A zeolite and evaluation the morphological characteristic.

In this study, the antimicrobial activity of titanium dioxide (TiO2), zinc oxide (ZnO), and TiO2/ZnO nanoparticles supported into 4A zeolite (4A z) was assessed. Based on antimicrobial experiments, minimum inhibitory concentration (MIC90), minimum bactericidal concentration (MBC), fractional inhibitory concentration (FIC) and disc diffusion test were determined after 24 h of contact with the prepared nanocomposites. These results are in agreements with the results of disc diffusion test. During the experiments, the numbers of viable bacterial cells of Staphylococcus aureus, Pseudomonas fluorescens, Listeria monocytogenes and Escherichia coli O157:H7 decreased significantly. The crystallinity and morphology of nanoparticles were investigated by X-ray diffraction patterns (XRD), elemental mapping at the microstructural level by scanning electron microscopy (SEM) with energy dispersive X-ray spectrometry (EDS), and transmission electron microscopy (TEM). As a result, it was demonstrated that TiO2/ZnO nanoparticles supported in 4A zeolite could lead to an optimum activity as antimicrobial agents.

Nanoparticles and Zeolites: Antibacterial Effects and their Mechanism against Pathogens.

Nowadays, distribution and microorganism resistance against antimicrobial compounds have caused crucial food safety problems. Hence, nanotechnology and zeolite are recognized as new approaches to manage this problem due to their inherent antimicrobial activity. Different studies have confirmed antimicrobial effects of Nano particles (NPs) (metal and metal oxide) and zeolite, by using various techniques to determine antimicrobial mechanism. This review includes an overview of research with the results of studies about antimicrobial mechanisms of nanoparticles and zeolite. Many researches have shown that type, particle size and shape of NPs and zeolite are important factors showing antimicrobial effectiveness. The use of NPs and zeolite as antimicrobial components especially in food technology and medical application can be considered as prominent strategies to overcome pathogenic microorganisms. Nevertheless, further studies are required to minimize the possible toxicity of NPs in order to apply suitable alternatives for disinfectants and antibacterial agents in food applications.

Effect of the of Zeolite Containing Silver-Zinc Nanoparticles on the Push out Bond Strength of Mineral Trioxide Aggregate in Simulated Furcation Perforation.

STATEMENT OF THE PROBLEM: Recently, zeolite has been regarded to improve the properties of dental materials such as mineral trioxide aggregate (MTA). PURPOSE: The aim of the present study was to evaluate the effect of incorporating zeolite/silver/zinc (Ze/Ag/Zn) composite at 2 wt% to MTA powder on the push-out bond strength in simulated furcation perforations. MATERIALS AND METHOD: Furcal perforations, measuring 1.3 mm in diameter and 2 mm in height, were simulated in 40 human mandibular first molars. The samples were allocated to two groups (n=20) based on the material used for the repair of perforations. In the group 1, MTA and in the group 2, MTA plus Ze/Ag/Zn (2%) was used. The samples were incubated at 37°C for 1 week. Then the universal testing machine was employed to measure bond strength. The resistance of materials to dislodgment was recorded in MPa. Data were analyzed using t-test. Statistical significance was set at p< 0.05. RESULTS: The push-out bond strength in the group 1 (6.40±1.98 MPa) was significantly higher than that in the group 2 (2.1±0.6 MPa) with p= 0.001. CONCLUSION: Under the limitations of the present study, it can be concluded that incorporation of Ze/Ag/Zn at 2 wt% to MTA powder had a negative effect on the push-out bond strength.

In vitro induction of odontogenic activity of human dental pulp stem cells by white Portland cement enriched with zirconium oxide and zinc oxide components.

Background . The aim of this in vitro study was to investigate the effect of zinc oxide (ZnO) and zirconium oxide (ZrO2) microparticles (MPs) and nanoparticles (NPs) in combination with white Portland cement (WPC) on odontogenic capacity of human dental pulp stem cells over a period of 21 days. Methods . Synthesized ZnO and ZrO2 particles were characterized using scanning electron microscopy and transmission electron microscopy. The viability of human dental pulp stem cells was measured by a 3-(4,5-dimethylthiazolyl-2-yl)-2,5- diphenyltetrazolium bromide assay at 7-, 14- and 21-day intervals after seeding on WPC disks enriched with ZnO and ZrO2 MPs and NPs. Odontogenic potential of ZnO and ZrO2 particles in combination with WPC was investigated by alkaline phosphatase (ALP) activity and ionized calcium level of supernatant culture media at different time intervals. Data were analyzed using one-way ANOVA and post hoc Tukey tests. Results . All the materials exhibited cell viability over a 21-day period, except for WPC with ZnO NPs on day 7, although it was not statistically significant (P>0.05). The ALP activity and ionized calcium level increased in all the groups compared to the control group (P<0.05). ZnO NPs had superior effect on odontogenic activity and calcium ion release compared to ZnO MPs (P=0.046). There was no significant difference between ZrO2 MPs and NPs in odontogenic activity (P>0.05). Conclusion . WPC enriched with ZnO and ZrO2 increased ALP activity and calcium ion release of human dental pulp stem cells over a period of 21 days in vitro.

Titanium Dioxide Nanoparticle/Gelatin: A Potential Burn Wound Healing Biomaterial.

INTRODUCTION: Over the past few decades, the application of nanotechnology has gained progressive interest for the regeneration of injured and burned tissues. OBJECTIVE: This study evaluates the effects of titanium dioxide (TiO2) nanoparticle (NP)/gelatin on burn wound healing in mice. MATERIALS AND METHODS: Sixty healthy male BALB/c mice with a full-thickness burn wound were randomized into 4 experimental groups of 15 animals each: (1) control group was treated with normal saline; (2) gelatin group was treated with gelatin-based ointment; (3) silver sulfadiazine group was treated with silver sulfadiazine 1% ointment; and (4) TiO2 NP/gelatin group (TNG) received TiO2 NP/gelatin. Wound size was measured on postoperative days 2, 6, 10, 14, 18, and 21, and histopathological studies of tissue samples were performed on postop days 7, 14, and 21. RESULTS: The wound area reduction indicated that there was a significant difference between the TNG and other groups (P < .05). Quantitative histological and morphometric studies and the mean rank gained from the qualitative studies demonstrated that there was a significant difference between the TNG and other groups (P < .05). CONCLUSIONS: In this study, TNG offered potential advantages in burn wound healing acceleration and improvement through angiogenesis stimulation, fibroblast proliferation, and granulation tissue formation in the early phases of healing. In addition, factors such as accelerated wound repair associated with earlier wound contraction and stability of the damaged area by rearrangement of granulation tissue and collagen fibers were also advantages of TNG.

Antibacterial Effect of Two Nano Zinc Oxide Gel Preparations Compared to Calcium Hydroxide and Chlorhexidine Mixture.

INTRODUCTION: The aim of this study was to compare the antibacterial effects of two gels containing zinc oxide and zinc oxide/silver nanoparticles and a mixture of calcium hydroxide and 0.12% chlorhexidine as intracanal medicaments in root canals contaminated with Enterococcus faecalis (E. faecalis) at different time intervals. METHODS AND MATERIALS: After preparation and culturing of E. faecalis in 132 single root teeth, the initial count of bacteria was performed. Then, different materials as intracanal medicaments were used in periods of 3, 7 and 14 days (group 1: calcium hydroxide with 0.12% CHX paste; group 2 zinc oxide nanoparticles gel; group 3: zinc oxide/silver nanoparticles gel; group 4: normal saline as the control group). After the specified time, intracanal medicament was removed and the final count of bacteria was performed. Antibacterial effect of materials was counted by measuring the percentage reduction in the colony counts (RCC). Data were analyzed using the descriptive statistics (Mean±SD) and multi-factorial analysis of variance (by taking into account the effect of the time factor on the dependent variable). RESULTS: There were no statistically significant differences among mean RCC of different time intervals in each group (P=0.09). However, the differences in mean RCC of different dressing materials were significant (P<0.001). The effect of interaction between time and materials was significant (P=0.015). Comparison of the antibacterial effects of experimental agents at different time intervals showed that the mean RCC in group 1 was higher than other groups (P<0.001). The difference in antibacterial effect between groups 2 and 3 was not significant (P>0.05). The minimum antibacterial effect was observed in group 4 (P<0.0001). CONCLUSIONS: The mixture of calcium hydroxide/chlorhexidine as an intracanal medicament was more effective than zinc oxide and zinc oxide/silver nanoparticles gels.

Immobilization and microencapsulation of Lactobacillus caseii and Lactobacillus plantarum using zeolite base and evaluating their viability in gastroesophageal-intestine simulated condition / Inmovilización y microencapsulación de Lactobacillus caseii y Lactobacillus plantarum usando base de zeolita y evaluando su viabilidad en condiciones simuladas de gastroesofágico-intestino

Aims: In order to improve survival in gastrointestinal conditions, probiotic bacteria, i.e. we developed a new encapsulation method of probiotics based on zeolite and by calcium-alginate zeolite-starch as an effective method for safer delivery of probiotics. Material and Methods: Lactobacillus casei (ATCC 39392) and Lactobacillus plantarum (ATCC 29521) were used as probiotics. After microorganism’s immobilization on zeolite base, encapsulation was done by calcium-alginate zeolite-starch with the extrusion method. Afterwards, they were incubated in the simulated gastric and intestinal condition. Viability of these bacteria was calculated on the basis of time required to reduce the logarithmic base in the microbial population. SEM techniques were used to study the appearance of the capsules. Results: after incubation for 120 min under simulated gastric condition and 180 min in intestinal juice conditions (pH=8.2), the count of alive L. casei and L. plantarum cells were 6.3 log cfu/ml and 7.3 log cfu/ ml. However, for controlling the cells, this value was zero and 2.1 log cfu/ml respectively. Conclusion: According to the results, we had an increase of the survival rate of L. casei and L. plantarum in gastroesophageal-intestine simulated condition. These results indicated good efficacy and high performance of zeolite for immobilization and microencapsulation of probiotics

Objetivos: Para mejorar la supervivencia en condiciones gastrointestinales de las bacterias probióticas, hemos desarrollado un nuevo método de encapsulación de probióticos a base de zeolita y almidón de zeolita de alginato de calcio como método eficaz para la administración más segura de probióticos. Material y métodos: se utilizaron Lactobacillus casei (ATCC 39392) y Lactobacillus plantarum (ATCC 29521) como probióticos. Después de la inmovilización del microorganismo en la base de zeolita, la encapsulación se realizó mediante zeolita-almidón de alginato de calcio con el método de extrusión. Posteriormente, se incubaron en la condición gástrica e intestinal simulada. La viabilidad de estas bacterias se calculó sobre la base del tiempo requerido para reducir la base logarítmica en la población microbiana. Las técnicas SEM se usaron para estudiar la apariencia de las cápsulas. Resultados: después de la incubación durante 120 minutos bajo condición gástrica simulada y 180 minutos en condiciones de jugo intestinal (pH = 8,2), el recuento de células vivas de L. casei y L. plantarum fue de 6,3 log ufc / ml y de 7,3 log ufc / ml. Sin embargo, para controlar las células, este valor era cero y 2,1 log cfu / ml respectivamente

The effect of photodynamic therapy and polymer solution containing nano-particles of Ag /ZnO on push-out bond strength of the sealers AH-Plus and MTA Fillapex.

BACKGROUND: The aim of this in vitrostudy was to examine and compare the effect of photodynamic therapy and solution containing nano particles Ag/ZnO on adhesion of endodontic sealers to dentinal walls of human root canal. MATERIAL AND METHODS: Ninty single-rooted human teeth were selected and their clinical crown was cut from the cemento-enamel junction zone. Canals were prepared by RaCe rotary system and the smear layer was removed using 17% EDTA and 5.25% NaOCl. Samples were randomly divided into two groups of AH Plus and MTA Fillapex based on the sealer type and each group based on antimicrobial method was divided into two sub-groups of photodynamic therapy and polymer containing nano particles of Ag / ZnO and a control sub-group (N = 15). After obturation of canals with gutta-percha and sealers mentioned, the samples were incubated for a week at a humidity of 95% and 37°C and then 2mm thick discs were prepared from the middle region of roots for Push-out test. The maximum failure force was recorded in newton and converted to MPa. Then, 3 random specimens of each subgroup were evaluated by scanning electron microscopy. Statistical analysis was performed by Two way ANOVA and (P<0.05) was considered significant. RESULTS: The highest (4.84 ± 1.63) and lowest (0.16 ± 0.075) push-out bond strength values were obtained in (AH Plus-PDT) and (MTA Fillapex-Ag/ZnO) respectively. Independent of antimicrobial method, AH Plus bond strength was significantly higher than the MTA Fillapex (p<0.001). For both sealers, PDT increased the bond strength significantly (p<0.001). CONCLUSIONS: Photodynamic therapy has a positive effect on the bond strength of AH Plus and MTA Fillapex sealers. Key words:AH Plus, MTA Fillapex, Nano particles, Photodynamic therapy, Push-out.

Zeolite-silver-zinc nanoparticles: Biocompatibility and their effect on the compressive strength of mineral trioxide aggregate.

BACKGROUND: This study was carried out to evaluate the biocompatibility of zeolite-silver-zinc (Ze-Ag-Zn) nanoparticles and their effect on the compressive strength of Mineral Trioxide Aggregate (MTA). MATERIAL AND METHODS: Biocompatibility was evaluated by an MTT assay on the pulmonary adenocarcinoma cells with 0.05, 0.1, 0.25, 0.5, 1 and 5 mg/mL concentrations of Ze-Ag-Zn. For compressive strength test, four groups containing 15 stainless-steel cylinders with an internal diameter of 4 and a height of 6 mm were prepared and MTA (groups 1 and 2) or MTA + 2% Ze-Ag-Zn (groups 3 and 4) were placed in the cylinders. The compressive strength was evaluated using a universal testing machine 4 days after mixing in groups 1 and 3, and 21 days after mixing in groups 2 and 4. RESULTS: There was no significant difference between cytotoxicity of different concentrations. The highest (52.22±18.92 MPa) and lowest (19.57±5.76 MPa) compressive strength were observed in MTA group after 21 days and in MTA + 2% Ze-Ag-Zn group after four days, respectively. The effect of time and 2% Ze-Ag-Zn on the compressive strength were significant (P<0.05). Mixing MTA with Ze-Ag-Zn significantly reduced and passage of time from day four to 21 significantly increased the compressive strength. CONCLUSIONS: Mixing MTA with 2% Ze-Ag-Zn had an adverse effect on the compressive strength of MTA, but this combination had no cytotoxic effects. Key words:Compressive strength, Cytotoxicity, Mineral Trioxide Aggregate, Nanoparticle, Zeolite-Silver-Zinc.

Biocompatibility of Mineral Trioxide Aggregate with TiO2 Nanoparticles on Human Gingival Fibroblasts.

BACKGROUND: The New compositions of white mineral trioxide aggregate (WMTA) or use of various additives like nanoparticles might affect MTA's ideal characteristics This study was performed to evaluate the cytotoxicity of WMTA and WMTA with Titanium dioxide (TiO2) nanoparticles (1% weight ratio) at different storage times after mixing on human gingival fibroblasts (HGFs). MATERIAL AND METHODS: HGFs were obtained from the attached gingiva of human premolars. HGFs were cultured in Dulbecco's Modified Eagle medium, supplemented with 10% fetal calf serum, penicillin and streptomycin. The cells were exposed to WMTA (groups 1 and 2) and WMTA+TiO2 (groups 3 and 4). The fifth and sixth groups served as controls. Each group contained 15 wells. After 24h (groups 1, 3 and 5) and 48 h (groups 2, 4 and 6) of exposure, HGF viability was determined by Mosmann's tetrazolium toxicity (MTT) assay. Statistical analysis of the data was performed by using one-way analysis of variance and Tukey post hoc test, with significance of p < 0.05. RESULTS: With both materials, the viability of HGFs significantly decrased with increasing the incubation time from 24h to 48 h (P<0.05). There was no significant difference between the materials regarding HGF viability (P>0.05). CONCLUSIONS: Under the limitations of the present study, incorporation of TiO2 nanoparticles into MTA at 1 wt% had no negative effect on its biocompatibility. Key words:Cytotoxicity, fibroblast, MTA, MTT assay, nanoparticle, TiO2.