Presence Of Phosphate Buffered Saline Research Articles

Effect of cardiolipin on the lamellarity and elongation of liposomes hydrated in PBS

Lamellarity and shape are important factors in the formation of vesicles and determine their role in biological systems and pharmaceutical applications. Cardiolipin (CL) is a major lipid in many biological membranes and exerts a great influence on their structural organization due to its particular structure and physico-chemical properties. Here, we used small-angle X-ray and neutron scattering to study the effects of CL with different acyl chain lengths and saturations (CL14:0, CL18:1, CL18:2) on vesicle morphology and lamellarity in membrane models containing mixtures of phosphatidylcholine and phosphatidylethanolamine with different acyl chain lengths and saturations (C14:0 and C 18:1). Measurements were performed in the presence of Phosphate Buffer Saline (PBS), at 37°C, to better reflect physiological conditions, which resulted in strong effects on vesicle morphology, depending on the type and amount of CL used. The presence of small quantities of CL (from 2.5%) reduced inter-membrane correlations and increased perturbation of the membrane, an effect which is enhanced in the presence of matched shorter saturated acyl chains, and mainly unilamellar vesicles (ULV) are formed. In extruded vesicles, employed for SANS experiments, flattened vesicles are observed partly due to the hypertonic effect of PBS, but also influenced by the type of CL added.Our experimental data from SAXS and SANS revealed a strong dependence on CL content in shaping the membrane microstructure, with an apparent optimum in the PC:CL mixture in terms of promoting reduced correlations, preferred curvature and elongation. However, the use of PBS caused distinct differences from previously published studies in water in terms of vesicle shape, and highlights the need to investigate vesicle formation under physiological conditions in order to be able to draw conclusions about membrane formation in biological systems.

Bioactivity of Calcium Silicate-Based Endodontic Materials: A Comparative in vitro Evaluation

ABSTRACT Background: Bioactivity refers to the ability of a material to interact with living organisms or biological systems in a way that elicits a specific response. In the context of materials science and medicine, bioactivity is particularly important because it can determine the suitability of material for various applications. Objective: To evaluate and compare different commercially available calcium silicate-based materials regarding: 1. Morphological and elemental analysis at the dentin/material interface. 2. Calcium and silicon release and uptake by adjacent root canal dentine by evaluating the calcium and silicon incorporation depth in adjacent root canal dentin. Materials and Methods: This study examined four calcium silicate-based cements: Biodentine, MTA Angelus, BioAggregate, and MTA Plus. One hundred extracted human teeth with intact apices and no cavities were selected. Root sections measuring 3 mm in length were created at the mid-root level using low-speed diamond discs. Bioactivity was evaluated at 1, 7, 30, and 90 days, respectively. Results: The principal composition of the interfacial dentine layer and incorporation of calcium and silicon into dentine was measured at 1, 7, 30, and 90 days. Statistical analysis was performed by multiple comparisons using post hoc Tukey HSD. Conclusion: All the materials have shown bioactivity, i.e. release of calcium, silicon, and their uptake in the adjacent dentin in the presence of phosphate-buffered saline.

Tumor-Selective Cascade-Amplified Dual-Prodrugs Activation for Synergistic Oxidation-Chemotherapy

Tumor-Selective Cascade-Amplified Dual-Prodrugs Activation for Synergistic Oxidation-Chemotherapy

BSA-stabilized manganese phosphate nanoflower with enhanced nanozyme activity for highly sensitive and rapid detection of glutathione

The development of an efficient protein-inorganic nanohybrid with superior nanozyme activity for highly sensitive detection of glutathione (GSH) is essential for early diagnosis of human diseases. Herein, a rapid and highly sensitive colorimetric assay using self-assembled bovine serum albumin-hydrated manganese phosphate nanoflowers (MnPNF) as a biomimic oxidase is developed for GSH detection in human serum. The BSA can complex with Mn2+ to serve the nucleation center to produce MnPNF in the presence of phosphate-buffered saline (PBS). The morphology and surface characterization results show that the MnPNF is assembled with hierarchical nanoplates to form 500 nm nanoflowers. The oxidase-like activity of MnPNF is based on the redox reaction with 3,3′,5,5′-tetramethylbenzidine. However, the addition of GSH can reduce MnPNF to Mn2+, and subsequently supresses the oxidase-like activity and a yellow color at 450 nm is observed in the presence of H2SO4. The MnPNF-based nanozyme exhibits excellent sensing ability toward GSH detection, and a good linear relationship between the change in absorbance at 450 nm and the added amounts of GSH at 50 nM–10 μM with low limits of detection of 20 and 26.6 nM in the PBS and diluted human serum, respectively, is observed. Moreover, the sensing probe shows a superior selectivity over the other 16 interferences, which drive the determination of GSH feasible in real human serum. Since the MnPNF can be simply prepared at room temperature and no functionalization is required, this assay can be used to design the highly efficient biomimic oxidase for effective sensing of GSH and other disease-related biomolecules in biological fluid samples.

Development of Gelatin-Silk Sericin Incorporated with Poly(vinyl alcohol) Hydrogel-Based Nanocomposite for Articular Cartilage Defects in Rat Knee Joint Repair.

Sericin, a silk protein, has a high potential for use as an extracellular matrix in tissue engineering applications. In this study, novel gelatin (GEL) and silk sericin (SS) were incorporated with a polyvinyl alcohol) PVA hydrogel nanocomposite (GEL-SS-PVA) scaffold that can be applied to repair cartilage. Glutaraldehyde was used as a cross-linking agent, with hydrochloric acid acting as an initiator. The microstructure characteristics of the obtained GEL-SS and GEL-SS-PVA scaffolds were also examined using FTIR and XRD spectra and their enhanced thermal stability was assessed by TGA. The blended GEL-SS and GEL-SS-PVA scaffolds were confirmed by SEM analysis to be highly porous with optimum pore sizes of 172 and 58 µm, respectively. Smaller pore sizes and improved uniformity were observed as the concentration of PVA in the GEL-SS-PVA scaffold increased. PVA decreased the tensile strength and elongation of the membranes but increased the modulus. Swelling studies showed high swellability and complete degradation in the presence of phosphate-buffered saline. Cytocompatibility of the GEL-SS-PVA scaffolds showed that these had the highest potential to promote cell proliferation as evaluated with standard microscopy using L929 fibroblasts. The prepared GEL-SS composite scaffold incorporated with the PVA hydrogel was implanted in full-thickness articular cartilage defects in rats. The repair effect of cartilage defects was observed and evaluated among the GEL-SS-PVA, GEL-SS, and control operation groups. The defects were almost completely repaired after 14 weeks in the GEL-SS-PVA group, thereby indicating that the GEL-SS-PVA composite had a favorable effect on articular cartilage defects in rat knee joint repair.

Preparation and characterization of curcumin-loaded polymeric nanomicelles to interference with amyloidogenesis through glycation method.

Amyloid fibrils, including β-amyloid (Aβ) fibrils, are protein aggregates that form under certain conditions, associated with neurodegeneration that interfere with neural synaptic transmission resulting in some neural disorders, such as Alzheimer's disease. The aim of this study is to inhibit amyloidogenesis by using preparatory polymeric nanomicelles as therapeutic agents and also as nanocarriers for curcumin to target Aβ fibrils through the glycation method of bovine serum albumin (BSA) in the presence of phosphate-buffered saline. Polymeric nanomicelles were prepared from phosphatidylethanolamine-distearoyl methoxypolyethylene glycol conjugates in the presence and absence of curcumin and then the morphological and structural characteristics of the nanomicelles were characterized in detail. Following the preparation of unloaded and curcumin-loaded nanomicelles with the desired size and properties, their effects on BSA glycation/fibrillation process were investigated. The samples were analyzed by thioflavin T (ThT) fluorescence and advanced glycation end (AGE) products autofluorescence measurements. The results showed that ThT fluorescence related to the formation of β-sheets and AGE autofluorescence (associated with AGE production) decreased in the presence of curcumin-loaded nanomicelles more than other samples. In conclusion, the promising effect of curcumin-loaded nanomicelles on inhibition of amyloidogenesis through glycation process due to curcumin release and thus their ability to prevent the formation and accumulation of amyloid fibrils and so to suppress the Alzheimer's disease progression has been proven and can go for further investigations.

Development of co-solvent freeze-drying method for the encapsulation of water-insoluble thiostrepton in sterically stabilized micelles

The purpose of this work was to develop a practical and scalable method to encapsulate the hydrophobic antibiotic thiostrepton (TST) in sterically stabilized micelles (SSM). Using the conventional method of thin-film hydration, we encapsulated up to 5 drug molecules per SSM (diameter ∼ 16 nm). However, since this method is not suitable for large-scale production – a limiting factor for clinical translation – we applied the co-solvent freeze-drying method using tert-butanol (TBA): water co-solvent system. We found that the presence of phosphate-buffered saline (PBS) salts in the lyophilized cake accelerated the reconstitution time and allowed efficient drug encapsulation without the formation of larger drug particles. In addition, TBA proportion of 50% (v/v) was sufficient to maintain both phospholipid and drug in solution prior to the freeze-drying. The increase of drug and phospholipid concentrations in the formulation extended the reconstitution time and led to drug precipitation. Therefore, to increase the strength of the formulation, we prepared lyophilized cakes with lower phospholipid content (5 mM) and reconstituted them in one-third of the fill volume. In conclusion, we found optimum conditions to prepare TST-SSM using the co-solvent freeze-drying method. This scalable production method can facilitate the further clinical development and industrial production of TST-SSM nanomedicine.

On-Chip Stochastic Detection of Silver Nanoparticles without a Reference Electrode.

We report the electrochemical detection of 20 nm silver nanoparticles at a chip-based microelectrode array (MEA) without the need for a conventional reference electrode. This is possible due to the system's open-circuit potential allowing the oxidation of silver nanoparticles in the presence of phosphate-buffered saline (PBS). The hypothesis is confirmed by modulating the open-circuit potential via addition of ascorbic acid in solution, effectively inhibiting the detection of silver nanoparticle events. Employing the reference-free detection concept, we observe a linear relationship between the nanoparticle impact frequency at the microelectrodes and the nanoparticle concentration. This allows for viable quantification of silver nanoparticle concentrations in situ. The presented concept is ideal for the development of simple lab-on-a-chip or point-of-use systems enabling fast and low-cost screening of nanoparticles.

Potential of surfactant-coated nanoparticles to improve brain delivery of arylsulfatase A

The lysosomal storage disorder (LSD) metachromatic leukodystrophy (MLD) is caused by a deficiency of the soluble, lysosomal hydrolase arylsulfatase A (ASA). The disease is characterized by accumulation of 3-O-sulfogalactosylceramide (sulfatide), progressive demyelination of the nervous system and premature death. Enzyme replacement therapy (ERT), based on regular intravenous injections of recombinant functional enzyme, is in clinical use for several LSDs. For MLD and other LSDs with central nervous system (CNS) involvement, however, ERT is limited by the blood-brain barrier (BBB) restricting transport of therapeutic enzymes from the blood to the brain. In the present study, the potential of different types of surfactant-coated biodegradable nanoparticles to increase brain delivery of ASA was evaluated. Three different strategies to bind ASA to nanoparticle surfaces were compared: (1) adsorption, (2) high-affinity binding via the streptavidin-biotin system, and (3) covalent binding. Adsorption allowed binding of high amounts of active ASA. However, in presence of phosphate-buffered saline or serum rapid and complete desorption occurred, rendering this strategy ineffective for in vivo applications. In contrast, stable immobilization with negligible dissociation was achieved by high-affinity and covalent binding. Consequently, we analyzed the brain targeting of two stably nanoparticle-bound ASA formulations in ASA−/− mice, an animal model of MLD. Compared to free ASA, injected as a control, the biodistribution of nanoparticle-bound ASA was altered in peripheral organs, but no increase of brain levels was detectable. The failure to improve brain delivery suggests that the ASA glycoprotein interferes with processes required to target surfactant-coated nanoparticles to brain capillary endothelial cells.

Influence of salivary washout on drug delivery to the oral cavity using coated microneedles: An in vitro evaluation

The objective of this study was to determine whether in buccal tissues, after insertion and removal of coated microneedles, the presence of saliva over the insertion site can lead to loss of the deposited drug, and if saliva can influence in vitro permeation of the drug across the tissue. Microneedles were coated with sulforhodamine (SRD), which was used as a model drug, and inserted in to porcine buccal mucosa in vitro. Fluorescence microscopy was used to study microneedle coating quality and the diffusion of SRD through the mucosa. Permeation experiments were conducted for simulated dynamic or static salivary flow by adding 100μL/h or 100, 200 or 300μL of phosphate buffered saline (PBS) in the donor compartment of the Franz diffusion cells, into which buccal tissue after insertion of SRD-coated microneedles was placed. Microscopy showed that microneedles were uniformly coated with SRD and that SRD was successfully delivered in to the mucosa. Some SRD remained in the tissue even after 24h, despite presence of PBS on top of the coated microneedle insertion site. It was found that salivary washout can result in loss of drug that has been deposited in oral cavity mucosal tissues using coated microneedles, and presence of fluid over the coated microneedle insertion site can increase flux across the tissue. Thus, it is advisable to include salivary flow during in vitro studies related to the use of coated microneedles for drug delivery to the oral cavity in order to not obtain misleading results.

Carbon Nanotube-Based Dual-Gated Junctionless Field-Effect Transistor for Acetylcholine Detection

A compact n-type carbon nanotube (CNT)-based junctionless field-effect transistor (FET) for acetylcholine detection has been fabricated by integrating chitosan/nickel oxide as sensing membrane with CNTFET using chemical solution process. To improve the sensing performances higher than Nernstian, dual-gated junctionless CNTFET has been considered here. Electrical response has been carried out after immobilization of acetylcholine esterase using digital multimeter in presence of phosphate buffer saline of 50 mM and pH 7 in a glass pot. Experimental results show good linearity for acetylcholine concentration from 0.01 to 0.2 mM and improved sensitivity of 1.25 V/decade at room temperature. Limit of detection and Michaelis–Menten constant have been found to be 0.37 $\mu \text{M}$ and 0.2 mM, respectively. Insignificant interference observed while the sensor was tested with other clinical parameters.

Co-delivery of siRNA and hypericin into cancer cells by hyaluronic acid modified PLGA-PEI nanoparticles

Context: Malignant tumors cause more death because of the resistance of the hypoxic cancer cell toward radiotherapy. Targeting for hypoxic cancer area and gene silencing to overcome the hypoxia are two kinds of important therapeutic strategies for treating tumors.Objective: In order to explore the combined effects of gene therapy and hypericin (Hy) on tumor cells, hypoxia-inducible factor 1 alpha (HIF-1α) small interfering ribonucleic acid (siRNA) was transfected into the hypoxic human nasopharyngeal carcinoma (CNE2) cells using Hy-encapsulated nanocomplexes (Hy-HPP NPs) as a carrier which would achieve dual targeting to the tumor necrosis area.Materials and methods: NPs were prepared by emulsion–diffusion–evaporation method. Formulations were evaluated by conducting in vitro physicochemical studies, electrophoresis, in vivo study, and biochemical studies.Results and discussions: Hy-loaded nanoparticles with a mean size of around 160 nm was able to enhance the accumulation in the tumors by enhanced permeability and retention effect. The electrophoresis confirmed the good stability of siRNA/Hy-HPP NPs in the presence of phosphate-buffered saline (pH 7.4), competitive heparin, and RNase. The results of transfection showed that the uptake of siRNA was significantly increased up to 50% in CNE2 cells. The level of the HIF-1α with Hy-encapsulated nanocomplexes was significantly reduced to 30% in the transfected CNE2 cells. In vivo studies, the carrier exhibited higher intensity at the tumor tissue cells and higher affinity toward the necrotic tumor tissue.Conclusion: Results demonstrated that Hy-HPP NPs could significantly enhance the tranfection efficiency of siRNA, suggesting Hy-encapsulated nanoparticle as an efficient gene carrier. The co-delivery of HIF-1α siRNA (siHIF-1α) and Hy could efficiently decrease the level of HIF-1α and increase the affinity toward necrotic tissues. Hence, this is a promising strategy for further application in radiotherapy.

Carbon nanofillers incorporated electrically conducting poly ε-caprolactone nanocomposite films and their biocompatibility studies using MG-63 cell line

Poly e-caprolactone (PCL)-based nanocomposite films were prepared by solvent casting method with different electrically conducting carbon nanofillers like carbon nanofiber (CNF), nanographite and liquid exfoliated graphite. These nanocomposite films show remarkable increase in both surface and bulk electrical conductivity. Continuous network of nanofillers in polymer matrix was observed under high-resolution transmission electron microscopy (HRTEM). The spreading resistance images in AFM showed the presence of nanofillers on the nanocomposite films. These films reveal strong directional effect in electrical conductivity towards longitudinal direction than transverse. PCL film dispersed with 10 % (w/w) CNF showed an electrical conductivity of 19 S/m at longitudinal direction as compared to 1 S/m at transverse direction. This can be best explained with the arrangement of nanofillers along longitudinal direction during solution casting method which is evident from HRTEM images. The electrical conductivity of the nanocomposite films increased in the presence of phosphate buffer saline and simulated body fluid with time. MTT and nuclear staining experiments with osteoblast MG63 cells clearly demonstrated good biocompatibility of these materials. Among all the nanofillers, CNF looks most promising for biomedical applications of PCL-based conducting nanocomposites, as it shows high electrical conductivity and good cell proliferation.

Fabrication and characterization of junctionless carbon nanotube field effect transistor for cholesterol detection

We have reported fabrication and characterization of polyaniline (PANI)/zinc oxide (ZnO) membrane-based junctionless carbon nanotube field effect transistor deposited on indium tin oxide glass plate for the detection of cholesterol (0.5–22.2 mM). Cholesterol oxidase (ChOx) has been immobilized on the PANI/ZnO membrane by physical adsorption technique. Electrical response has been recorded using digital multimeter (Agilent 3458A) in the presence of phosphate buffer saline of 50 mM, pH 7.0, and 0.9% NaCl contained in a glass pot. The results of response studies for cholesterol reveal linearity as 0.5–16.6 mM and improved sensitivity of 60 mV/decade in good agreement with Nernstian limit ∼59.2 mV/decade. The life time of this sensor has been found up to 5 months and response time of 1 s. The limit of detection with regression coefficient (r) ∼ 0.998 and Michaelis-Menten constant (Km) were found to be ∼0.25 and 1.4 mM, respectively, indicating high affinity of ChOx to cholesterol. The results obtained in this work show negligible interference with glucose and urea.

Highly sensitive potassium-doped polypyrrole/carbon nanotube-based enzyme field effect transistor (ENFET) for cholesterol detection.

Highly sensitive potassium (K)-doped carbon nanotube (CNT) and polypyrrole (PPy) nanocomposite membrane-based enzyme field effect transistor (ENFET) has been fabricated on indium tin oxide (ITO) for detection of cholesterol. P-type graphene has been deposited as substrate on ITO glass electrochemically. N-type graphene has been deposited in source and drain regions. Zirconium dioxide (ZrO2) has been deposited on the channel region as gate insulator. K/PPy/CNT composite has been deposited as sensing membrane on the top of ZrO2 layer; 1μl of cholesterol oxidase (ChOx) has been immobilized on K/PPy/CNT membrane via physical adsorption technique. The response of K/PPy/CNT/FET has been studied using Agilent 3458A digital multimeter in presence of phosphate buffer saline (PBS) of 50mM, pH7.0 and 0.9% NaCl contained in a glass pot. During measurement, 20μl cholesterol solutions (0.5 to 25mM) were poured into the pot through micropipette each time. It has been found that K/PPy/CNT/FET has linearly varied from 0.5 to 20mM. The sensitivity of this FET has been found to be ~400μA/mM/mm(2) with regression coefficient (r) ~ 0.998. The proposed ENFET has response time of 1s and stability up to 6months. The experiment has been repeated 10 times, and only 2.0% output variation has been observed. The limit of detection (LoD) and Michaelis-Menten constant (K m) were found to be ~1.4 and 2.5mM, respectively. The results obtained in this work show negligible interference (3.7%) with uric acid, glucose and urea.

Wound healing properties of a 3-D scaffold comprising soluble silkworm gland hydrolysate and human collagen

Biomaterials that serve as scaffolds for cell proliferation and differentiation are increasingly being used in wound repair. In this study, the potential regenerative properties of a 3-D scaffold containing soluble silkworm gland hydrolysate (SSGH) and human collagen were evaluated. The scaffold was generated by solid–liquid phase separation and a freeze–drying method using a homogeneous aqueous solution. The porosity, swelling behavior, protein release, cytotoxicity, and antioxidative properties of scaffolds containing various ratios of SSGH and collagen were evaluated. SSGH/collagen scaffolds had a high porosity of 61–81% and swelling behavior studies demonstrated a 50–75% increase in swelling, along with complete protein release in the presence of phosphate-buffered saline. Cytocompatibility of the SSGH/collagen scaffold was demonstrated using mesenchymal stem cells from human umbilical cord. Furthermore, SSGH/collagen efficiently attenuated oxidative stress-induced cell damage. In an in vivo mouse model of wound healing, the SSGH/collagen scaffold accelerated wound re-epithelialization over a 15-day period. Overall, the microporous SSGH/collagen 3-D scaffold maintained optimal hydration of the exposed tissues and decreased wound healing time. These results contribute to the generation of advanced wound healing materials and may have future therapeutic implications.

Evaluation of biocidal efficacy of copper alloy coatings in comparison with solid metal surfaces: generation of organic copper phosphate nanoflowers

To analyse the biocidal efficacy of thermal sprayed copper surfaces. Copper alloy sheet metals containing >60% copper have been shown to exhibit potent biocidal activity. Surface biocidal activity was assessed by epifluorescence microscopy. After 2-h exposure at 20 °C in phosphate-buffered saline (PBS), contact killing of Gram-negative Escherichia coli and Gram-positive Staphylococcus epidermidis by brass sheet metal and phosphor bronze was 3-4-times higher than that by stainless steel. SEM observations revealed that the surface membranes of both bacterial strains were slightly more irregular when exposed to brass sheet metal than stainless steel. However, when exposed to phosphor bronze coating, E. coli were 3-4 times larger with irregular membrane morphology. In addition, the majority of the cells were associated with spherical carbon-copper-phosphate crystalline nanostructures characteristic of nanoflowers. The membranes of many of the S. epidermidis exhibited blebbing, and a small subset was also associated with nanoflowers. Our data indicate that increasing the surface roughness of copper alloys had a pronounced impact on the membrane integrity of Gram-positive and, to a lesser degree, Gram-negative bacteria. In the presence of PBS, carbon-copper-phosphate-containing nanoflowers were formed, likely nucleated by components derived from killed bacteria. The intimate association of the bacteria with the nanoflowers and phosphor bronze coating likely contributed to their nonreversible adhesion. Thermal spraying of copper alloys provides a strategy for the rapid coating of three-dimensional organic and inorganic surfaces with biocidal copper alloys. Our study demonstrates that the macroscale surface roughness generated by the thermal spray process enhances the biocidal activity of copper alloys compared with the nanoscale surface roughness of copper sheet metals. Moreover, the coating surface topography provides conditions for the rapid formation of organic copper phosphate nanocrystals/nanoflowers.

Irreversible Heavy Chain Transfer to Hyaluronan Oligosaccharides by Tumor Necrosis Factor-stimulated Gene-6

The covalent transfer of heavy chains (HCs) from inter-α-inhibitor (IαI) to hyaluronan (HA) via the protein product of tumor necrosis factor-stimulated gene-6 (TSG-6) forms the HC-HA complex, a pathological form of HA that promotes the adhesion of leukocytes to HA matrices. The transfer of HCs to high molecular weight (HMW) HA is a reversible event whereby TSG-6 can shuffle HCs from one HA molecule to another. Therefore, HMW HA can serve as both an HC acceptor and an HC donor. In the present study, we show that transfer of HCs to low molecular weight HA oligosaccharides is an irreversible event where subsequent shuffling does not occur, i.e. HA oligosaccharides from 8 to 21 monosaccharide units in length can serve as HC acceptors, but are unable to function as HC donors. We show that the HC-HA complex is present in the synovial fluid of mice subjected to systemic and monoarticular mouse models of rheumatoid arthritis. Furthermore, we demonstrate that HA oligosaccharides can be used, with TSG-6, to irreversibly shuffle HCs from pathological, HMW HC-HA to HA oligosaccharides, thereby restoring HC-HA matrices from the inflamed joint to their normal state, unmodified with HCs. This process was also effective for HC-HA in the synovial fluid of human rheumatoid arthritis patients (in vitro).

Development of a Novel Polygalacturonic Acid-Gelatin Blend Scaffold Fabrication and Biocompatibility Studies for Tissue-Engineering Applications

In this study, we report the enhanced osteoblast differentiation of mouse embryonic stem cell (mESC) on a novel polygalacturonic acid (PGA)/gelatin scaffold. The matrices of various PGA/geletin ratios were fabricated, biophysically characterized, and optimized for cell culture applications. Blended 2% PGA/gelatin scaffolds were highly porous and were robust with enhanced mechanical strength. Swelling studies showed they had high swelling capacity (six-fold higher than only gelatin scaffold) along with complete degradation in the presence of phosphate-buffered saline. Cytocompatibility of the matrices was evaluated using mouse fibroblast 3T3-L1 cell line showing normal spreading and proliferation as assessed by scanning electron microscopy (SEM) and MTT assay. Among different blends of PGA/gelatin, 2% PGA/gelatin (2PG) scaffold showed the optimum physical and biological compatibility for use in cell culture and differentiation of mESC, especially for osteoblast differentiation. The scaffold, as reported in this study, presents a promising tool for tissue engineering applications.

Uptake of calcium and silicon released from calcium silicate–based endodontic materials into root canal dentine

To compare Biodentine and White ProRoot mineral trioxide aggregate (MTA) with regard to Ca and Si uptake by adjacent root canal dentine in the presence of phosphate-buffered saline (PBS). Root canals of bovine incisor root segments were instrumented, filled with either Biodentine or MTA (n = 20 each) and then immersed in Ca-and Mg-free PBS for 1, 7, 30 or 90 days (n = 5 each). Unfilled, unimmersed dentine specimens (n = 5) served as controls. The specimens were sectioned longitudinally, and the ultrastructure of the dentine-material interface and the elemental composition/distribution in the material-adjacent dentine were analysed using a wavelength-dispersive X-ray spectroscopy electron probe microanalyser with image observation function. Data were statistically analyzed using one-way anova and Tukey's honestly significant difference test or the Mann-Whitney U-test. Along the material-dentine interface, both materials formed a tag-like structure that was composed of either Ca- and P-rich crystalline deposits or the material itself. The width of a Ca- and Si-rich layer detected along the dentine layer of the material-dentine interface showed increases over time. The Ca- and Si-rich layer width was significantly larger (P < 0.05) in Biodentine than MTA at 30 and 90 days. Both Biodentine and MTA caused the uptake of Ca and Si in the adjacent root canal dentine in the presence of PBS. The dentine element uptake was more prominent for Biodentine than MTA.