Concentration Of CaCl2 Solution Research Articles

The Study of Calcium Chloride Effect on Silver Nanoparticles Capping with Roselle Extract Granule against Aggregatibacter actinomycetemcomitans

Abstract Objectives The primary aim of this research is to investigate the influence of calcium chloride on the synthesis of silver nanoparticles coated with roselle extract and enclosed within alginate and calcium chloride (SNP-Ro-CaCl2) beads, designated as SNP-Ro-CaCl2 beads. Additionally, the study aims to assess their antimicrobial activity. Materials and Methods For the preparation of SNP-Ro-CaCl2 beads, SNPs and alginate gel were mixed, followed by dropping in three different concentrations of CaCl2 solution (1%, 3%, and 5% w/v). The morphological structure of the SNP-Ro-CaCl2 beads was analyzed using a stereoscope and scanning electron microscope (SEM). Over a period of 14 days, the release of SNPs was monitored using ultraviolet-visible (UV-Vis) spectroscopy. Additionally, the activity against Aggregatibacter actinomycetemcomitans was evaluated using the disk diffusion technique. Statistical Analysis The data for this experiment were analyzed using one-way analysis of variance (ANOVA) and Scheffe's method. Results The results revealed that varying concentrations of calcium chloride had distinct crosslinking effects on alginate, resulting in different voids and porosity within the SNP-Ro-CaCl2 beads. In the SNP-Ro-1% CaCl2 beads, the inner element exhibited higher porosity, facilitating faster activation and greater efficiency in releasing SNPs. Regarding activity against A. actinomycetemcomitans after 14 days, SNP-Ro-1% CaCl2 beads showed a larger inhibition zone diameter compared to other concentrations, while no statistically significant difference in the inhibition zone diameter was observed between SNP-Ro-3% CaCl2 and SNP-Ro-5% CaCl2 beads. Additionally, it was observed that the antimicrobial effectiveness diminished after 17 days through testing of the lifetimes of the three concentrations. Conclusions This study developed a method for depositing SNP-Ro into alginate gel and crosslinking it with CaCl2 to produce small beads for the sustained release of SNP-Ro in periodontal lesions. Consequently, the SNP-Ro-CaCl2 beads have the potential to be developed as adjunctive locally delivered antimicrobial agents in periodontal therapy.

Composite Alginate Dialdehyde-Gelatin (ADA-GEL) Hydrogel Containing Short Ribbon-Shaped Fillers for Skeletal Muscle Tissue Biofabrication.

Skeletal muscle tissue can be severely damaged by disease or trauma beyond its ability to self-repair, necessitating the further development of biofabrication and tissue-engineering tools for reconstructive processes. Hence, in this study, a composite bioink of oxidized alginate (ADA) and gelatin (GEL) including cell-laden ribbon-shaped fillers is used for enhancing cell alignment and the formation of an anisotropic structure. Different plasma treatments combined with protein coatings were evaluated for the improvement of cell adhesion to poly(lactic-co-glycolic acid) (PLGA) ribbon surfaces. Oxygen plasma activation of 30 W for 5 min showed high immobilization of fibronectin as a protein coating on the PLGA ribbon surface, which resulted in enhanced cell adhesion and differentiation of muscle cells. Furthermore, the effect of various concentrations of CaCl2 solution, used for ionic cross-linking of ADA, on ADA-GEL physical and mechanical properties as well as encapsulated C2C12 cell viability and proliferation behavior was investigated. The pore area was measured via two approaches, cryofixation and lyophilization, which, in accordance with degradation tests and mechanical analysis, showed that 60 mM CaCl2 concentration is the optimum range for cross-linking of the formulation of ADA 2.5%w/v-GEL 3.75%w/v. These cross-linked hydrogels showed a compression modulus of 11.5 kPa (similar to the native skeletal muscle tissue), a high viability of C2C12 muscle cells (>80%), and a high proliferation rate during 7 days of culture. Rheological characterization of the ADA-GEL composite hydrogel containing short fillers (100 μm long) showed its suitability as a bioink with shear-thinning and flow behavior compared to ADA-GEL.

Encapsulation of Pomelo Peel Essential oil (Citrus maxima) Using the Alginate/Chitosan complex

Objective: This study aimed to determine appropriate parameters for encapsulating pomelo peel essential oil (Citrus maxima) using the alginate/chitosan complex. Methods: The investigated parameters included the concentration of sodium alginate solution (2 ‒ 3.5% w/v based on the volume of mixture), the concentration of pomelo essential oil (20 ‒ 40% w/w based on dry matter of wall marerials), the concentration of Tween 80 (0 ‒ 20% w/w based on dry matter of wall marerials), the concentration of CaCl2 solution (0.5 ‒ 3.5% w/v based on the volume of mixture), time (10 min – 20 min) and speed of emulsion homogenization (489-4402 × g), the concentration of chitosan solution (0.5 ‒ 2% w/v based on the volume of mixture), and pH of chitosan solution (4 ‒ 6). Results: The results showed encapsulation yield (EY%) and encapsulation efficiency (EE%) of 91.64% and 85.18%, respectively, when using the concentration of sodium alginate solution as 3% (w/v based on the volume of mixture), the concentration of essential oil as 30% (w/w based on dry matter of wall marerials), the concentration of Tween 80 as 15% (w/w based on dry matter of wall marerials), the concentration of CaCl2 solution as 1.5% (w/v based on the volume of mixture), homogenization time as 10 min and homogenization speed as 4402 × g, the concentration of chitosan as 2% (w/v based on the volume of mixture) and pH of Chitosan solution as 5. Conclusion: The alginate/chitosan complex was proven effective in encapsulating pomelo essential oil (Citrus maxima) on a laboratory scale. The resulting encapsulated particles had a relatively uniform size and a high ability to retain essential oils in the core of the particles. Further studies should be conducted to elucidate the mechanism of the encapsulation process and to additionally evaluate the physical and chemical properties of the encapsulated particles.

Preparation and Properties of Egg White Dual Cross-Linked Hydrogel with Potential Application for Bone Tissue Engineering

In this study, an egg white dual cross-linked hydrogel was developed based on the principle that the external stimulus can denature proteins and cause them to aggregate, forming hydrogel. The sodium hydroxide was used to induce gelation of the egg white protein, subsequently introducing calcium ions to cross-link with protein chains, thereby producing a dual cross-linked hydrogel. The characteristics of the dual cross-linked hydrogels-including the secondary structure, stability, microstructure, swelling performance, texture properties, and biosafety-were investigated to determine the effects of calcium ion on the egg white hydrogel (EWG) and evaluate the potential application in the field of tissue engineering. Results showed that calcium ions could change the β-sheet content of the protein in EWG after soaking it in different concentrations of CaCl2 solution, leading to changes in the hydrogen bonds and the secondary structure of polypeptide chains. It was confirmed that calcium ions promoted the secondary cross-linking of the protein chain, which facilitated polypeptide folding and aggregation, resulting in enhanced stability of the egg white dual cross-linked hydrogel. Furthermore, the swelling capacity of the EWG decreased with increasing concentration of calcium ions, and the texture properties including hardness, cohesiveness and springiness of the hydrogels were improved. In addition, the calcium cross-linked EWG hydrogels exhibited biocompatibility and cell-surface adhesion in vitro. Hence, this work develops a versatile strategy to fabricate dual cross-linked protein hydrogel with biosafety and cell-surface adhesion, and both the strategy and calcium-egg white cross-linked hydrogels have potential for use in bone tissue engineering.

Modeling the effect of physical crosslinking degree of pH and temperature responsive poly(NIPAAm-co-VSA)/alginate IPN hydrogels on drug release behavior

There is a growing demand to design and development of hydrogel based stimuli responsive drug-delivery systems due to possess several advantages, namely high drug loading capacity, target specific delivery, biocompatibility, reduced drug toxicity and controlled drug release. Because their drug release behavior is dependent on many factors, it is very difficult to accurately characterize these behaviors. So, the characterization of drug loading and release behaviors is very important from an industrial and academic point of view. In this study, pH and temperature responsive poly(NIPAAm-co-VSA)/Alginate interpenetrating polymer network (IPN) hydrogel was synthesized by free radical polymerization in the presence of Poly(NIPA-co-VSA) nano gels. Na-Alginate natural polymer was used to physically cross-link the hydrogels with the Ca2+ ions. To obtain physically crosslinked hydrogel series at different rates, hydrogels were kept in various concentrations of CaCl2 solutions. The mechanical, chemical and morphological properties of obtained hydrogel series were characterized by compression test, FT-IR and SEM analysis techniques. As a result of the mechanical tests, it was determined that the fracture strengths varied between 137 and 830 kPa. The doxorubicin (DOX) loading capacities of the hydrogels were determined to be between 86 and 161 mg DOX/g polymer by the solution impregnation method. Their DOX release behavior have been investigated as a function of time, pH, temperature and physical crosslinking degree of hydrogel. Experimentally obtained and highly complex DOX release behaviors were successfully modeled with the artificial neural network (ANN) technique.

Experimental investigation of influence of calcium ion (Ca2+) and pH on the shear strength of Taipei silty clay

ABSTRACT Electroosmotic chemical treatment is a technique for improving the strength of soft soil. This study examined the effects of injection duration, Ca2+ions concentration, and pH distribution on the shear strength of Taipei silty clay. Experimental tests were conducted by injecting calcium chloride (CaCl2) solution into Taipei silty clay during electroosmosis for various durations. After testing, the water content, pH, Ca2+ ions concentration, injection volume, drainage volume, and cone resistance were measured. The results indicated that the injection volume, drainage volume, Ca2+ ions concentration, and strength of the silty clay were low compared with the same measurements for kaolinite because Taipei silty clay consists mainly of illite, which results in the soil having a lower coefficient of electroosmotic permeability. The treatments of 12–48 h were insufficient for improving soil strength. However, the 120-h 1.5 M C120 injection treatment resulted in a moderate increase in soil strength due to consolidation and Ca2+ ions precipitation. By comparing our results with those of studies on kaolinite, we established a suitable injection procedure, which includes solutions for treatment duration and concentration of CaCl2 solution (i.e. 1.5 M C48, 0.2 M C120, and 0.75 M C120).

Molecular Dynamics Simulation of the Diffusion Mechanism of Chloride Ion between Different Phases of Cement-Based Concrete

The diffusion of chloride ions can cause corrosion of concrete buildings, thus reducing their service life. The diffusion of chloride ion in concrete is mainly carried out between the interfaces of different phases. In this article, Hamid model and Jennite model are used to represent C-S-H gel phase with different ratios of calcium to silicon (C/S), and Fe crystal is used to represent stainless steel phase. The diffusion behavior of chloride ion in calcium chloride (CaCl2) solution layer with a certain thickness, which is between gel phases, gel phase and stainless steel phase, was studied. A supercell molecular model containing upper and lower surface phases and CaCl2 solution in the middle was established. The effect of upper and lower surface type, the thickness of solution layer, and concentration of CaCl2 solution were investigated by molecular dynamics simulation. The results show that when the upper and lower surfaces are Fe and C-S-H crystals, respectively, the diffusion coefficient of chloride ion is one order of magnitude larger than that of both C-S-H crystals, where the diffusion coefficient of chloride ions decreases with the increase of C/S on the whole. The relative concentration distribution of calcium ion and chloride ion in the solution layer were analyzed, demonstrating that the surface of C-S-H crystals are negatively charged near the side of the solution and the diffusion of chloride ions is related to the number of charges; the diffusion coefficients of chloride ions increase with both the concentration and thickness of CaCl2 solution layer.

The Effect of Calcium Chloride on Drought Tolerance of Mulberry

Drought stress greatly affects the quality and yield of mulberry leaves, which eventually influences the production of silkworm cocoon. In this study, the effect of calcium chloride on drought tolerance of mulberry was investigated. Different concentrations of CaCl2 solutions were sprayed on the leaves of mulberry under drought condition, and the physiological and biochemical responses were measured. As a result, the spray of CaCl2 on leaves (CaCl2-spray-on-leaves) was proved to have gradual increases in measure parameters as compared to CaCl2-untreated case under the same drought condition; furthermore, 20mM CaCl2-treated group showed a significant increase (P<0.05), which indicates the optimal CaCl2 concentration for improving the drought tolerance of mulberry. This study demonstrated that CaCl2-spray-on-leaves can be an effective measure to ameliorate the drought tolerance of mulberry in the severe-drought areas.

Chemical Route for Synthesis of Citric Acid from Citrus Juices

Citric acid is the main tricarboxylic acid present in citrus fruits such as lemons, lime, oranges, grapefruit, grapes, etc. These fruits contain sufficient citric acid. The properties of citric acid make it an important additive for application in various industries such as the food, pharmaceuticals, disinfection, and cleaning industries. The aim of this experimental study is to produce citric acid from orange and grape juices. The chemical route for the synthesis of citric acid from citrus juices involves three steps: (i) Neutralization to adjust pH to 9-10 with 2.5 M NaOH solution, (ii) Addition of CaCl2 solution, and (iii) Acidification with H2SO4 solution to produce citric acid. Juice containing citric acid is neutralized with NaOH solution to obtain trisodium citrate. Then, trisodium citrate is added with CaCl2 solution to produce calcium citrate. Finally, calcium citrate is acidified with H2SO4 solution to collect crystals of citric acid. In this study, the fruits were crushed, juice filtered, neutralized, added CaCl2 solution, and acidified to obtain citric acid. The experiments were carried out by varying different volumes of 2.5 M NaOH solution during neutralization, concentrations of CaCl2 solution, and volume of H2SO4 solution. The percentage of citric acid yield collected from grape juice varied from 44.1 to 79.53%. Similarly, the percentage yield of citric acid was calculated to be from 60.1 to 96.3%. It was found that the percentage of citric acid yield increased with increasing pH and decreased with increasing CaCl2 concentration. Thus, it could be concluded that the orange juice yielded more citric acid than grape juice.

Inductive effects of exogenous calcium on the defense of kidney bean plants against Frankliniella occidentalis (Thysanoptera: Thripidae)

Calcium (Ca) is an essential macronutrient for plant growth. It can confer plants with resistance to abiotic stresses. However, little is understood about its role on biotic stresses. Frankliniella occidentalis (Thysanoptera: Thripidae) is one of the world’s most important invasive pests and poses a great threat to crops; meanwhile, it is hard to control due to its polyphagia and rapid reproduction. In order to clarify the effects of Ca on the induced defense of kidney bean plants against F. occidentalis by different application methods, we treated plants with different concentrations of CaCl2 solution using three methods, including spraying on leaf, root-irrigation, and seed soaking. The activities of defensive enzymes in leaves of kidney bean plants in response to F. occidentalis feeding as well as the developmental time of F. occidentalis were examined. The results showed that all the three treatment methods with different concentrations of CaCl2 solution could obviously induce activities of lipoxygenase (LOX), phenylalanine ammonia lyase (PAL), and β-1, 3-glucanase in leaves of kidney bean plants against F. occidentalis, while inductive effects of spraying the 10 mM CaCl2 on leaves were the best among all the treatments. Furthermore, we found that the developmental time of the whole immature stage of F. occidentalis feeding on plants sprayed with 10 mM CaCl2 was longer than those on control plants. Overall, our results indicated that the exogenous CaCl2 could enhance enzymatic activities in plants by thrips-induced effects, and spraying 10 mM CaCl2 on leaves of kidney bean plants showed the highest resistance against F. occidentalis.

Ion-exchanging dialysis as an effective method for protein entrapment in curdlan hydrogel.

The purpose of this study was to determine whether dialysis method allows for efficient protein entrapment in curdlan-based hydrogel. Thus, bovine serum albumin, a model of bioactive protein, was incorporated into curdlan matrix using ion-exchanging dialysis method against two concentrations of CaCl2 solution - 2% and 10%, respectively. Then, physicochemical, mechanical, and biological properties of the bovine serum albumin-loaded curdlan hydrogels were evaluated. Received results show that neither the polymer nor the entrapment procedure change the bovine serum albumin conformation (as proven by Fourier transform infrared spectroscopy and circular dichroism spectroscopy) and the process guarantees high protein entrapment efficiency (above 95%). The curdlan-based carrier obtained against 2% of CaCl2 solution was found to possess higher swelling ability, release greater amounts of bovine serum albumin (up to 4 weeks), and exhibit superior biocompatibility compared to curdlan-based carrier obtained against 10% of CaCl2 solution. Thus, dialysis method enables efficient protein entrapment in curdlan hydrogel and obtained protein carrier via dialysis method into 2% of CaCl2 solution may be considered as a promising protein delivery system especially for tissue engineering applications. It should be noted that we are the first who presented effective method for protein entrapment in curdlan hydrogel.

Improving Hydrophilic Barriers of Encapsulated Compounds in Ca-Alginate Microgel Particles through a New Ionotropic Gelation Method for Double Emulsion Droplets

The ability of encapsulation to protect hydrophilic–bioactive food compounds from harsh environments can be improved by strengthening the hydrophilic barriers of encapsulated food compounds in Ca-alginate microgel particles via the integration of oil into the microgels. This study introduces a one-step procedure to integrate water-in-oil (W/O) emulsion droplets directly into Ca-alginate microgels during the production using the impinging aerosols system. A water-in-oil-in-water (20 kg m−3 alginate solution) (W1/O/W2) double emulsion was prepared using a high speed homogeniser followed by a microfluidiser. The microstructure of the W1/O/W2 emulsion was analysed using optical and fluorescence microscopy. The mean diameters of the W1/O/W2 emulsion droplets and resultant microgels were in the range of 27.8–65.4 μm and 160–420 μm, respectively. Food dye was used as a proxy for a hydrophilic food compound and its release from the microgels was significantly decreased when it was encapsulated in the W/O emulsion droplets. Based on the numerical analysis, the presence of the W/O emulsion droplets in the gel network reduced the degree of gelation of the microgel because the diffusion rate of Ca2+ cation in the microgel is reduced. The degree of gelation of the W/O emulsion droplets encapsulated microgel is 0.6 when the diameter of the droplet is reduced to 77.5 μm and the concentration of CaCl2 solution is doubled to 22 kg m−3. The potentiality of the impinging aerosol system to produce Ca-alginate microgels to encapsulate hydrophilic compounds with improved barriers is presented in this work.

The surface wettability of brine in a tight oil reservoir

ABSTRACTBased on DSA100 instrumentation, the interactions between the chemical groups on the rock surface and brine were analyzed to study the abilities and microscopic mechanisms on reservoir characteristics of wettability controlled by Na+, Ca2+and Mn2+. The results show that that in the same solution, static and dynamic angle of each ions are consistent. When the concentration of CaCl2 solution is more than 0.5 mol/L, the contact angle will change greatly. Ca2+, Mn2+ can change the structural characteristics of tight reservoirs. This provides a theoretical basis for our study of low salinity water flooding and recovery ratio.

Use of non-adherent hydrogels to control the behaviour of human hepatocarcinoma cell lines

Event Abstract Back to Event Use of non-adherent hydrogels to control the behaviour of human hepatocarcinoma cell lines Jordi Gonzalez-Molina1*, Natasha Maurmann1* and Clare Selden1* 1 University College London, Institute for Liver and Digestive Health, United Kingdom Introduction: Cells are able to sense the physical and chemical properties of their surroundings mainly via proteins located in the plasma membrane. Integrins are transmembrane receptors that bind to components of the extracellular matrix sending information to the interior of the cell. The mechanical characteristics of the cellular environment have been shown to have a variety of effects on different cell types including differentiation and proliferation. Here we used non-adherent hydrogels, polymers that do not contain integrin-binding motifs, to study the effect of their mechanical properties on the behaviour of liver-derived cell lines capable of surviving in the absence of integrin signalling. Also, we studied the effect of high viscosity media applying these polymers, to mimic the viscosity of biological fluids, such as blood or mucus, on cells. Materials and Methods: Experiments were conducted with the hepatocarcinoma cell lines HepG2 and Huh7. To study the effect of the environmental stiffness of a complete non-adherent three-dimensional (3D) milieu, we encapsulated HepG2 cells in alginate or agarose hydrogels with varying stiffness. To achieve higher stiffness, greater percentages of polymer were used, and for alginate gels two different concentrations of CaCl2 solutions were applied to cross-link it. Also, addition of non-cross-linked alginate was used to study the effect of culture medium viscosity on HepG2 and Huh7 cells attached to conventional rigid polystyrene plates. Results and Discussion: In 3D cultures, cell proliferation in the softest alginate was 4 times greater than the cells in the stiffest alginate and spheroids were significantly larger (p<0.01). This was not explained by a loss of cell viability (always >95%) or reduced proliferation potential as demonstrated by releasing encapsulated cells from the alginate and re-seeding them on polystyrene plates. Flow cytometry analysis revealed an arrest at the G0/G1 (>92% of the cells) phases of the cell cycle in stiff hydrogels at early time points, however, later time points showed an accumulation of cells in the G2/M phases (40-50% of the cells) in all encapsulated cells. These data indicates that mechanical stimuli produced by the hydrogels are sensed by the cell cycle control machinery. Cells incubated for 4 days with viscous media (>1% alginate) changed to a fibroblast-like morphology, a reduced proliferation (p<0.05) and enhanced migration, suggesting that increased media viscosity might be involved in epithelial-mesenchymal transition. Conclusion: Using non-adherent hydrogels we demonstrated that cells are able to sense the mechanical properties of their environment without attaching to it. These results suggest modulation of the mechanical properties of the cellular environment or the signalling pathways involved in these processes may provide novel tools to control cancer cell proliferation and the metastatic process. Liver Group Charity; Wellcome Trust Keywords: Cell Proliferation, Hydrogel, cell phenotype, 3D scaffold Conference: 10th World Biomaterials Congress, Montréal, Canada, 17 May - 22 May, 2016. Presentation Type: Poster Topic: Mechanobiology of cells on biomaterials Citation: Gonzalez-Molina J, Maurmann N and Selden C (2016). Use of non-adherent hydrogels to control the behaviour of human hepatocarcinoma cell lines. Front. Bioeng. Biotechnol. Conference Abstract: 10th World Biomaterials Congress. doi: 10.3389/conf.FBIOE.2016.01.01062 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 27 Mar 2016; Published Online: 30 Mar 2016. * Correspondence: Dr. Jordi Gonzalez-Molina, University College London, Institute for Liver and Digestive Health, London, United Kingdom, Email1 Dr. Natasha Maurmann, University College London, Institute for Liver and Digestive Health, London, United Kingdom, n.maurmann@ucl.ac.uk Dr. Clare Selden, University College London, Institute for Liver and Digestive Health, London, United Kingdom, c.selden@ucl.ac.uk Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Jordi Gonzalez-Molina Natasha Maurmann Clare Selden Google Jordi Gonzalez-Molina Natasha Maurmann Clare Selden Google Scholar Jordi Gonzalez-Molina Natasha Maurmann Clare Selden PubMed Jordi Gonzalez-Molina Natasha Maurmann Clare Selden Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. 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Comparison of ultrasonic-assisted and regular leaching of germanium from by-product of zinc metallurgy

A major source of germanium recovery and also the source of this research is the by-product of lead and zinc metallurgical process. The primary purpose of the research is to investigate the effects of ultrasonic assisted and regular methods on the leaching yield of germanium from roasted slag containing germanium. In the study, the HCl–CaCl2 mixed solution is adopted as the reacting system and the Ca(ClO)2 used as the oxidant. Through six single factor (leaching time, temperature, amount of Ca(ClO)2, acid concentration, concentration of CaCl2 solution, ultrasonic power) experiments and the comparison of the two methods, it is found the optimum collective of germanium for ultrasonic-assisted method is obtained at temperature 80°C for a leaching duration of 40min. The optimum concentration for hydrochloric acid, CaCl2 and oxidizing agent are identified to be 3.5mol/L, 150g/L and 58.33g/L, respectively. In addition, 700W is the best ultrasonic power and an over-high power is adverse in the leaching process. Under the optimum condition, the recovery of germanium could reach up to 92.7%. While, the optimum leaching condition for regular leaching method is same to ultrasonic-assisted method, except regular method consume 100min and the leaching rate of Ge 88.35% is lower about 4.35%. All in all, the experiment manifests that the leaching time can be reduced by as much as 60% and the leaching rate of Ge can be increased by 3–5% with the application of ultrasonic tool, which is mainly thanks to the mechanical action of ultrasonic.

Fabrication of shape controllable alginate microparticles based on drop-on-demand jetting

Drop-on-demand jetting was combined with a gelation technique to fabricate alginate microparticles into varied shapes. First, uniform alginate microdroplets were generated by adjusting the parameters of the voltage waveform which is applied to a piezoelectric print-head. Next, the alginate microdroplets were solidified by calcium ions, resulting in the formation of alginate microparticles. The collision of alginate microdroplets with the surface of CaCl2 solution and a cross-linking reaction caused formation of microparticles of spherical, elliptical, tail-shaped, and other shapes. The effect of printing parameters including microdroplet velocity and concentration of CaCl2 solution on microparticle shape was systematically studied. We found that tail-shaped microparticles were better to form lines compared to spherical microparticles. Our findings can guide efforts for more precise fabrication of differently shaped alginate microparticles using drop-on-demand jetting for application in bioprinting, drug delivery, and cell encapsulation.

Fibroblasts attachment to CaCl2 hydrothermally treated titanium implant

Background/PurposeThis study investigated the effect of hydrothermal treatment with calcium chloride (CaCl2) solutions on fibroblast attachment and proliferation to titanium implants in the presence and absence of fetal bovine serum. Materials and methodsPure titanium specimens were prepared, polished (1500 grit), cleaned with ethanol, hydrothermally treated with CaCl2 solutions at 200 °C for 24 h (Ti–CaCl2). Two concentrations of CaCl2 solution were used (Ti–CaCl2 10 mM/L and Ti–CaCl2 20 mM/L). Titanium specimens without CaCl2 treatment were used as a control. Then, specimens were exposed to L-929 fibroblasts to test cellular attachment and proliferation after 30 min, 1 h, 2 h, 5 h, 1 day, 3 day and 1 week with and without fetal bovine serum (FBS). The percentage of viable attached cells (cells/ml) for each surface treatment was measured using trypan blue assay. Cellular growth on just culture plate material was used as a negative control. The data (n = 5) were statistically analyzed by ANOVA/Tukey test (p < 0.05). ResultsWithout FBS after 1 week, a statistically significant higher cell attachment to titanium control than to Ti–CaCl2 10 mM/L or Ti–CaCl2 20 mM/L was revealed. With FBS after 1 week, there was a significant lower cell attachment to Ti–CaCl2 20 mM/L than to titanium control. ConclusionsThe CaCl2 hydrothermally treated titanium showed lower evidence of fibroblasts attachment than pure titanium did, which means decreasing the liability of fibrosis, and hence, stronger bonding of CaCl2 hydrothermally treated titanium implant to bone (better osseointegration).

Investigation of charge inversion in silicon nanochannels with molecular dynamics simulation

Through molecular dynamics simulation, the ionic distributions in NaCl and CaCl2 solutions confined in 3-nm-high nanochannels were investigated. Different from the previous simulation model with artificial electrical neutrality, our model would reach equilibrium and electrical neutrality through ion exchange among the nanochannel region and the bulk sinks. It is observed that when the surface charge density is −0.101 C/m2, charge inversion occurs at 1.0 M concentration of CaCl2 solution, but not in NaCl solution due to the stronger correlation effect between Ca2+ ions near the charged surface, which is not considered in the mean field Poisson–Boltzmann equation. Our simulation results agree well with the experimental results by F.H.J. Van Der Heyden et al. In addition, with the increase in the surface charge density, the charge inversion can be induced in the monovalent solution and be strengthened in the divalent ionic solution.

Abstract 3232: Anticancer drug delivery utilizing a mucoadhesive hybrid gel for local regional gynecologic applications

Abstract Cervical cancer is one of the leading gynecological malignancies affecting women worldwide. Although surgical cytoreduction and systemic chemotherapy combined with radiation are standard therapies, accessibility to such treatment as well as nonspecific toxicity limit its efficacy. We hypothesize that the site-specific local application of anticancer drugs utilizing innovative delivery technologies will improve efficacy, reduce toxicity and provide cost-effective, accessible therapeutic options. To test this hypothesis, we developed a mucoadhesive, polymeric hybrid chitosan gel embedding drug containing alginate beads. An optimized gel was achieved by mixing 1% chitosan (w/v) with glycerol dissolved in acetic acid (AA) solution at a volume ratio of 1:2 or 1:3 (2% AA:glycerol). Alginate beads were formed by dropping alginate solution (2%, w/v) into various concentrations of CaCl2 solution. In testing swelling properties, dried alginate beads transforming into wet ones were capable of releasing the drug load. Beads obtained from 1% CaCl2 solution demonstrated optimal and stable swelling properties that were 40 times greater than other formulations. Such beads, loaded with cisplatin (CDDP) dissolved in 0.9% NaCl were prepared. The loaded CDDP concentration was confirmed by colorimetric assay with Sn2Cl2 after re-swelling of the dried beads. Drug loaded-beads contained an average of 0.2mg of CDDP per 10 mg of dried beads. There was a linear correlation (R2 = 0.92) between the swelling ratio of the alginate beads and the amount of CDDP released, allowing the ability to estimate CDDP concentration based on the swelling ratio. Drug-loaded dried alginate beads were placed into a chitosan solution resulting in a hybrid hydrogel. To test the feasibility of local application of the gel on a mucosal surface, we investigated the swelling and mucoadhesive properties on a 4cm2 section of mouse peritoneal sidewall. We confirmed the complete swelling of beads within the hybrid gel suggested sufficient release of CDDP from the beads onto a biological surface. Mucoadhesive properties and toxicity were evaluated in vivo by surgically placing a 1cm2 sized gel pellet into the left peritoneal sidewall of immune competent female mice. The hybrid gel remained in place for 72 hours exhibiting no signs of local inflammation, tissue damage or systemic toxicity. Our results strongly suggest the feasibility of application of this hybrid gel to various mucosal surfaces. Ongoing experiments will evaluate the efficacy and safety of our hybrid gel/CDDP as a radiation enhancer in the treatment of cervical cancer and for the treatment of cervical dysplasia. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3232. doi:10.1158/1538-7445.AM2011-3232

Characteristic parameters and operational curves of γ-Al2O3 nanofiltration membranes

The γ-Al2O3 nanofiltration membranes were manufactured by the sol-gel technique. The result of N2 adsorption and desorption test indicates that the characteristic parameters of the membranes: BJH desorption average pore diameter, BJH desorption cumulative volume of pores and BET surface area are about 3.9 nm, 0.33 cm3/g and 245 m2/g respectively, and the pore size distribution is very narrow. The operational curves of γ-Al2O3 nanofiltration membranes of the Ca2+ retention rate vs the trans-membrane pressure, feed concentration of solution treated and pH of solution treated were studied for the first time. It is found that the retention rate for Ca2+increases with the transmembrane pressure increasing and decreases with the feed concentration of CaCl2 solution increasing. The retention of Ca2+ is very much dependent on the pH of the solution. Minimal Ca2+ retention rate is found at the isoelectric point (pH = 7.5).