F. L. La Mantia, M. Ceraulo, M. Mistretta, M. Morreale
Purpose Biodegradable polymers are currently gaining importance in several fields, because they allow mitigation of the impact on the environment related to disposal of traditional, nonbiodegradable polymers, as well as reducing the utilization of oil-based sources (when they also come from renewable resources). Fibers made of biodegradable polymers are of particular interest, though, it is not easy to obtain polymer fibers with suitable mechanical properties and to tailor these to the specific application. The main ways to tailor the mechanical properties of a given biodegradable polymer fiber are based on crystallinity and orientation control. However, crystallinity can only marginally be modified during processing, while orientation can be controlled, either during hot drawing or cold stretching. In this paper, a systematic investigation of the influence of cold stretching on the mechanical and thermomechanical properties of fibers prepared from different biodegradable polymer systems was carried out. Methods Rheological and thermal characterization helped in interpreting the orientation mechanisms, also on the basis of the molecular structure of the polymer systems. Results and conclusions It was found that cold drawing strongly improved the elastic modulus, tensile strength and thermomechanical resistance of the fibers, in comparison with hot-spun fibers. The elastic modulus showed higher increment rates in the biodegradable systems upon increasing the draw ratio.
{"title":"Effect of Cold Drawing on Mechanical Properties of Biodegradable Fibers","authors":"F. L. La Mantia, M. Ceraulo, M. Mistretta, M. Morreale","doi":"10.5301/jabfm.5000328","DOIUrl":"https://doi.org/10.5301/jabfm.5000328","url":null,"abstract":"Purpose Biodegradable polymers are currently gaining importance in several fields, because they allow mitigation of the impact on the environment related to disposal of traditional, nonbiodegradable polymers, as well as reducing the utilization of oil-based sources (when they also come from renewable resources). Fibers made of biodegradable polymers are of particular interest, though, it is not easy to obtain polymer fibers with suitable mechanical properties and to tailor these to the specific application. The main ways to tailor the mechanical properties of a given biodegradable polymer fiber are based on crystallinity and orientation control. However, crystallinity can only marginally be modified during processing, while orientation can be controlled, either during hot drawing or cold stretching. In this paper, a systematic investigation of the influence of cold stretching on the mechanical and thermomechanical properties of fibers prepared from different biodegradable polymer systems was carried out. Methods Rheological and thermal characterization helped in interpreting the orientation mechanisms, also on the basis of the molecular structure of the polymer systems. Results and conclusions It was found that cold drawing strongly improved the elastic modulus, tensile strength and thermomechanical resistance of the fibers, in comparison with hot-spun fibers. The elastic modulus showed higher increment rates in the biodegradable systems upon increasing the draw ratio.","PeriodicalId":51074,"journal":{"name":"Journal of Applied Biomaterials & Biomechanics","volume":"15 1","pages":"70 - 76"},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5301/jabfm.5000328","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70593279","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Y. Maruo, G. Nishigawa, M. Irie, K. Yoshihara, T. Matsumoto, S. Minagi
Background This study evaluated the surface morphology, chemical composition and adhesiveness of lithium disilicate glass ceramic after acid etching with hydrofluoric acid or phosphoric acid. Methods Lithium disilicate glass ceramic specimens polished by 600-grit silicon carbide paper were subjected to one or a combination of these surface treatments: airborne particle abrasion with 50-μm alumina (AA), etching with 5% hydrofluoric acid (HF) or 36% phosphoric acid (Phos), and application of silane coupling agent (Si). Stainless steel rods of 3.6-mm diameter and 2.0-mm height were cemented onto treated ceramic surfaces with a self-adhesive resin cement (Clearfil SA Cement). Shear bond strengths between ceramic and cement were measured after 24-hour storage in 37°C distilled water. Results SEM images of AA revealed the formation of conventional microretentive grooves, but acid etching with HF or Phos produced a porous surface. Bond strengths of AA+HF+Si (28.1 ± 6.0 MPa), AA+Phos+Si (17.5 ± 4.1 MPa) and HF+Si (21.0 ± 3.0 MPa) were significantly greater than those of non-pretreated controls with Si (9.7 ± 3.7 MPa) and without Si (4.1 ± 2.4 MPa) (p<0.05). In addition, HF etching alone (26.2 ± 7.5 MPa) had significantly higher bond strength than AA alone (11.5 ± 4.0 MPa) (p<0.05). AA+HF, AA+Phos and HF showed cohesive failures. Conclusions Etching with HF or Phos yielded higher bond strength between lithium disilicate glass ceramic and self-adhesive resin cement without microcrack formation.
{"title":"Does Acid Etching Morphologically and Chemically Affect Lithium Disilicate Glass Ceramic Surfaces?","authors":"Y. Maruo, G. Nishigawa, M. Irie, K. Yoshihara, T. Matsumoto, S. Minagi","doi":"10.5301/jabfm.5000303","DOIUrl":"https://doi.org/10.5301/jabfm.5000303","url":null,"abstract":"Background This study evaluated the surface morphology, chemical composition and adhesiveness of lithium disilicate glass ceramic after acid etching with hydrofluoric acid or phosphoric acid. Methods Lithium disilicate glass ceramic specimens polished by 600-grit silicon carbide paper were subjected to one or a combination of these surface treatments: airborne particle abrasion with 50-μm alumina (AA), etching with 5% hydrofluoric acid (HF) or 36% phosphoric acid (Phos), and application of silane coupling agent (Si). Stainless steel rods of 3.6-mm diameter and 2.0-mm height were cemented onto treated ceramic surfaces with a self-adhesive resin cement (Clearfil SA Cement). Shear bond strengths between ceramic and cement were measured after 24-hour storage in 37°C distilled water. Results SEM images of AA revealed the formation of conventional microretentive grooves, but acid etching with HF or Phos produced a porous surface. Bond strengths of AA+HF+Si (28.1 ± 6.0 MPa), AA+Phos+Si (17.5 ± 4.1 MPa) and HF+Si (21.0 ± 3.0 MPa) were significantly greater than those of non-pretreated controls with Si (9.7 ± 3.7 MPa) and without Si (4.1 ± 2.4 MPa) (p<0.05). In addition, HF etching alone (26.2 ± 7.5 MPa) had significantly higher bond strength than AA alone (11.5 ± 4.0 MPa) (p<0.05). AA+HF, AA+Phos and HF showed cohesive failures. Conclusions Etching with HF or Phos yielded higher bond strength between lithium disilicate glass ceramic and self-adhesive resin cement without microcrack formation.","PeriodicalId":51074,"journal":{"name":"Journal of Applied Biomaterials & Biomechanics","volume":"15 1","pages":"100 - 93"},"PeriodicalIF":0.0,"publicationDate":"2016-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5301/jabfm.5000303","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70592384","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Background The aim of this study was to investigate the effectiveness of different remineralization agents by quantitative light-induced fluorescence digital Biluminator™ (QLF-D). Methods Artificial caries lesions were created, and the teeth were divided according to the tested materials: (i) distilled water, (ii) acidulated phosphate fluoride (APF), (iii) Curodont Repair (CR), (iv) ammonium hexafluorosilicate (SiF) and (v) ammonium hexafluorosilicate plus cetylpyridinium chloride (SiF + CPC). After treatment procedures, each of the samples was placed in artificial saliva. After demineralization and 1 and 4 weeks of remineralization procedures, fluorescence loss and lesion areas were measured with QLF-D. Data were statistically analyzed (α = 0.05). Results The fluorescence values of the demineralized enamel specimens treated with the various agents differed significantly compared with pretreatment values for both 1 and 4 weeks (p<0.05). At 4 weeks, the highest fluorescence gain was calculated in the CR, APF and SiF groups compared with the control (p<0.05). Conclusions APF, SiF and CR groups yielded greater remineralization ability than SiF + CPC and control groups.
{"title":"Measuring the Remineralization Potential of Different Agents with Quantitative Light-Induced Fluorescence Digital Biluminator","authors":"E. Kucukyilmaz, S. Savaş","doi":"10.5301/jabfm.5000317","DOIUrl":"https://doi.org/10.5301/jabfm.5000317","url":null,"abstract":"Background The aim of this study was to investigate the effectiveness of different remineralization agents by quantitative light-induced fluorescence digital Biluminator™ (QLF-D). Methods Artificial caries lesions were created, and the teeth were divided according to the tested materials: (i) distilled water, (ii) acidulated phosphate fluoride (APF), (iii) Curodont Repair (CR), (iv) ammonium hexafluorosilicate (SiF) and (v) ammonium hexafluorosilicate plus cetylpyridinium chloride (SiF + CPC). After treatment procedures, each of the samples was placed in artificial saliva. After demineralization and 1 and 4 weeks of remineralization procedures, fluorescence loss and lesion areas were measured with QLF-D. Data were statistically analyzed (α = 0.05). Results The fluorescence values of the demineralized enamel specimens treated with the various agents differed significantly compared with pretreatment values for both 1 and 4 weeks (p<0.05). At 4 weeks, the highest fluorescence gain was calculated in the CR, APF and SiF groups compared with the control (p<0.05). Conclusions APF, SiF and CR groups yielded greater remineralization ability than SiF + CPC and control groups.","PeriodicalId":51074,"journal":{"name":"Journal of Applied Biomaterials & Biomechanics","volume":"15 1","pages":"101 - 106"},"PeriodicalIF":0.0,"publicationDate":"2016-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5301/jabfm.5000317","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70592449","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Duarte, D. Maniglio, Nuno Sousa, J. Mano, R. Reis, C. Migliaresi
Background This study investigated the preparation of ordered patterned surfaces and/or microspheres from a natural-based polymer, using the breath figure and reverse breath figure methods. Methods Poly(D,L-lactic acid) and starch poly(lactic acid) solutions were precipitated in different conditions – namely, polymer concentration, vapor atmosphere temperature and substrate – to evaluate the effect of these conditions on the morphology of the precipitates obtained. Results The possibility of fine-tuning the properties of the final patterns simply by changing the vapor atmosphere was also demonstrated here using a range of compositions of the vapor phase. Porous films or discrete particles are formed when the differences in surface tension determine the ability of polymer solution to surround water droplets or methanol to surround polymer droplets, respectively. In vitro cytotoxicity was assessed applying a simple standard protocol to evaluate the possibility to use these materials in biomedical applications. Moreover, fluorescent microscopy images showed a good interaction of cells with the material, which were able to adhere on the patterned surfaces after 24 hours in culture. Conclusions The development of patterned surfaces using the breath figure method was tested in this work for the preparation of both poly(lactic acid) and a blend containing starch and poly(lactic acid). The potential of these films to be used in the biomedical area was confirmed by a preliminary cytotoxicity test and by morphological observation of cell adhesion.
本研究利用呼吸图法和反呼吸图法研究了从天然聚合物制备有序图案表面和/或微球的方法。方法将聚乳酸(D, l -乳酸)和淀粉型聚乳酸(淀粉型聚乳酸)溶液在不同的条件下(即聚合物浓度、蒸汽气氛温度和底物)进行沉淀，评价这些条件对所得沉淀物形貌的影响。结果利用气相的一系列组成，简单地通过改变蒸汽气氛来微调最终图案性质的可能性也得到了证明。当表面张力的差异分别决定了聚合物溶液包围水滴的能力或甲醇包围聚合物水滴的能力时，形成多孔膜或离散颗粒。采用简单的标准方案评估体外细胞毒性，以评估在生物医学应用中使用这些材料的可能性。此外，荧光显微镜图像显示细胞与材料的良好相互作用，在培养24小时后，细胞能够粘附在图案表面上。结论在制备聚乳酸和含有淀粉和聚乳酸的共混物时，使用呼吸图法测试了图案表面的发展。初步的细胞毒性试验和细胞粘附的形态学观察证实了这些薄膜在生物医学领域的应用潜力。
{"title":"From Honeycomb- to Microsphere-Patterned Surfaces of Poly(Lactic Acid) and a Starch-Poly(Lactic Acid) Blend via the Breath Figure Method","authors":"A. Duarte, D. Maniglio, Nuno Sousa, J. Mano, R. Reis, C. Migliaresi","doi":"10.5301/jabfm.5000281","DOIUrl":"https://doi.org/10.5301/jabfm.5000281","url":null,"abstract":"Background This study investigated the preparation of ordered patterned surfaces and/or microspheres from a natural-based polymer, using the breath figure and reverse breath figure methods. Methods Poly(D,L-lactic acid) and starch poly(lactic acid) solutions were precipitated in different conditions – namely, polymer concentration, vapor atmosphere temperature and substrate – to evaluate the effect of these conditions on the morphology of the precipitates obtained. Results The possibility of fine-tuning the properties of the final patterns simply by changing the vapor atmosphere was also demonstrated here using a range of compositions of the vapor phase. Porous films or discrete particles are formed when the differences in surface tension determine the ability of polymer solution to surround water droplets or methanol to surround polymer droplets, respectively. In vitro cytotoxicity was assessed applying a simple standard protocol to evaluate the possibility to use these materials in biomedical applications. Moreover, fluorescent microscopy images showed a good interaction of cells with the material, which were able to adhere on the patterned surfaces after 24 hours in culture. Conclusions The development of patterned surfaces using the breath figure method was tested in this work for the preparation of both poly(lactic acid) and a blend containing starch and poly(lactic acid). The potential of these films to be used in the biomedical area was confirmed by a preliminary cytotoxicity test and by morphological observation of cell adhesion.","PeriodicalId":51074,"journal":{"name":"Journal of Applied Biomaterials & Biomechanics","volume":"15 1","pages":"31 - 42"},"PeriodicalIF":0.0,"publicationDate":"2016-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5301/jabfm.5000281","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70592489","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Campos-Delgado, K. L. Castro, J. Munguia-Lopez, Ana K. González, M. Mendoza, B. Fragneaud, R. Verdan, J. Araujo, F. J. González, H. Navarro‐Contreras, I. Pérez-Maldonado, A. De León-Rodríguez, C. Achete
Background Driven by the potential biological applications of graphene, many groups have studied the response of cells exposed to graphene oxide (GO). In particular, investigations of bacteria indicate that there are 2 crucial parameters, which so far have only been investigated separately: GO size and exposure methodology. Our study took into account both parameters. We carefully characterized the samples to catalog sizes and structural properties, and tested different exposure methodologies: exposure in saline solution and in the presence of growth media. Furthermore, we performed experiments with peripheral blood mononuclear cells exposed to our GO materials. Methods Atomic force microscopy, scanning electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and transmission electron microscopy were used to characterize the morphology and composition of different samples of GO: GO-H2O, GO-PBS and GO-MG. Our samples had 2D sizes of ∼100 nm (GO-H2O and GO-PBS) and >2 µm (GO-MG). We tested antibacterial activity and cytotoxicity toward peripheral blood mononuclear cells of 3 different GO samples. Results A size-dependent growth inhibition of Escherichia coli (DH5 α) in suspension was found, which proved that this effect depends strongly on the protocol followed for exposure. Hemocompatibility was confirmed by exposing peripheral blood mononuclear cells to materials for 24 hours; viability and apoptosis tests were also carried out. Conclusions Our experiments provide vital information for future applications of GO in suspension. If its antibacterial properties are to be potentiated, care should be taken to select 2D sizes in the micrometer range, and exposure should not be carried out in the presence of grow media.
{"title":"Effect of Graphene Oxide on Bacteria and Peripheral Blood Mononuclear Cells","authors":"J. Campos-Delgado, K. L. Castro, J. Munguia-Lopez, Ana K. González, M. Mendoza, B. Fragneaud, R. Verdan, J. Araujo, F. J. González, H. Navarro‐Contreras, I. Pérez-Maldonado, A. De León-Rodríguez, C. Achete","doi":"10.5301/jabfm.5000325","DOIUrl":"https://doi.org/10.5301/jabfm.5000325","url":null,"abstract":"Background Driven by the potential biological applications of graphene, many groups have studied the response of cells exposed to graphene oxide (GO). In particular, investigations of bacteria indicate that there are 2 crucial parameters, which so far have only been investigated separately: GO size and exposure methodology. Our study took into account both parameters. We carefully characterized the samples to catalog sizes and structural properties, and tested different exposure methodologies: exposure in saline solution and in the presence of growth media. Furthermore, we performed experiments with peripheral blood mononuclear cells exposed to our GO materials. Methods Atomic force microscopy, scanning electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and transmission electron microscopy were used to characterize the morphology and composition of different samples of GO: GO-H2O, GO-PBS and GO-MG. Our samples had 2D sizes of ∼100 nm (GO-H2O and GO-PBS) and >2 µm (GO-MG). We tested antibacterial activity and cytotoxicity toward peripheral blood mononuclear cells of 3 different GO samples. Results A size-dependent growth inhibition of Escherichia coli (DH5 α) in suspension was found, which proved that this effect depends strongly on the protocol followed for exposure. Hemocompatibility was confirmed by exposing peripheral blood mononuclear cells to materials for 24 hours; viability and apoptosis tests were also carried out. Conclusions Our experiments provide vital information for future applications of GO in suspension. If its antibacterial properties are to be potentiated, care should be taken to select 2D sizes in the micrometer range, and exposure should not be carried out in the presence of grow media.","PeriodicalId":51074,"journal":{"name":"Journal of Applied Biomaterials & Biomechanics","volume":"14 1","pages":"423 - 430"},"PeriodicalIF":0.0,"publicationDate":"2016-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5301/jabfm.5000325","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70592945","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Matteoli, A. Virga, I. Paladini, R. Mencucci, A. Corvi
Background The aim of this work was to evaluate the effect of cross-linking (CXL) on ex vivo porcine corneal elastic properties, using an inflation procedure. Methods Twelve corneas were subjected to standard CXL (370 nm, 3 mW/cm2, 30 minutes), while 12 were used as controls. Corneal thickness was measured by Visante optical coherence tomography, before and immediately after treatment, and before inflation test. Both intraocular pressure and radial apical cornea displacement were measured during inflation. Stress-strain curves were obtained by applying the linear shell theory. The elastic modulus was evaluated by calculating the slope of the stress-strain curves. Results Results showed a statistically significant increase in elastic modulus (p<0.0001), with a mean of 3,868 ± 502 kPa for cross-linked corneas and 2,727 ± 238 kPa for untreated corneas, when subjected to high pressure (40-60 kPa). CXL significantly increased porcine cornea stiffness by about 42%. Findings did not show any significant difference within the physiological range of pressure (2-4 kPa). Conclusions The inflation test has been proven to be a valuable tool for the investigation of corneal biomechanics, maintaining both integrity and geometry of corneal tissue.
{"title":"Investigation into the Elastic Properties of ex vivo Porcine Corneas Subjected to Inflation Test after Cross-Linking Treatment","authors":"S. Matteoli, A. Virga, I. Paladini, R. Mencucci, A. Corvi","doi":"10.5301/jabfm.5000262","DOIUrl":"https://doi.org/10.5301/jabfm.5000262","url":null,"abstract":"Background The aim of this work was to evaluate the effect of cross-linking (CXL) on ex vivo porcine corneal elastic properties, using an inflation procedure. Methods Twelve corneas were subjected to standard CXL (370 nm, 3 mW/cm2, 30 minutes), while 12 were used as controls. Corneal thickness was measured by Visante optical coherence tomography, before and immediately after treatment, and before inflation test. Both intraocular pressure and radial apical cornea displacement were measured during inflation. Stress-strain curves were obtained by applying the linear shell theory. The elastic modulus was evaluated by calculating the slope of the stress-strain curves. Results Results showed a statistically significant increase in elastic modulus (p<0.0001), with a mean of 3,868 ± 502 kPa for cross-linked corneas and 2,727 ± 238 kPa for untreated corneas, when subjected to high pressure (40-60 kPa). CXL significantly increased porcine cornea stiffness by about 42%. Findings did not show any significant difference within the physiological range of pressure (2-4 kPa). Conclusions The inflation test has been proven to be a valuable tool for the investigation of corneal biomechanics, maintaining both integrity and geometry of corneal tissue.","PeriodicalId":51074,"journal":{"name":"Journal of Applied Biomaterials & Biomechanics","volume":"14 1","pages":"163 - 170"},"PeriodicalIF":0.0,"publicationDate":"2016-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5301/jabfm.5000262","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70591989","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nathan Zaltsman, Dana Kesler-Shvero, E. Weiss, N. Beyth
Background Resin-based dental materials allow bacterial growth on their surface and lack antibacterial activity, leading to functional and esthetic failure. Quaternary ammonium polyethyleneimine (QPEI) nanoparticles (NPs) incorporated in resin-based composite at 2% wt/wt have demonstrated prolonged and complete inhibition of bacterial growth. This study focused on optimization of QPEI NP synthesis to reduce the concentration required for bacterial growth inhibition. The objective here was to enhance antimicrobial efficacy by excess base neutralization, using phosphoric or hydrochloric acid, and by using surfactants. Methods QPEI NP variants were prepared (i) under controlled neutralization of acid, using NaHCO3, (ii) under controlled carbonate ion neutralization with HCl or H3PO4 and (iii) by treatment with N-lauroylsarcosine or glycerol monostearate. NPs incorporated in the dental materials were examined for their antibacterial effect against Enterococcus faecalis. Results Controlled addition of NaHCO3 resulted in modified QPEI NPs with an increased ability to inhibit bacterial growth. Surface treatment with N-lauroylsarcosine resulted in enhanced antibacterial activity at 0.5% wt/wt concentration in acrylate and epoxy resin-based dental materials. Conclusions The antimicrobial efficacy of QPEI NP may be improved significantly by controlling the addition of NaHCO3, neutralization of excess base and the surface-agent effect.
{"title":"Synthesis Variants of Quaternary Ammonium Polyethyleneimine Nanoparticles and Their Antibacterial Efficacy in Dental Materials","authors":"Nathan Zaltsman, Dana Kesler-Shvero, E. Weiss, N. Beyth","doi":"10.5301/jabfm.5000269","DOIUrl":"https://doi.org/10.5301/jabfm.5000269","url":null,"abstract":"Background Resin-based dental materials allow bacterial growth on their surface and lack antibacterial activity, leading to functional and esthetic failure. Quaternary ammonium polyethyleneimine (QPEI) nanoparticles (NPs) incorporated in resin-based composite at 2% wt/wt have demonstrated prolonged and complete inhibition of bacterial growth. This study focused on optimization of QPEI NP synthesis to reduce the concentration required for bacterial growth inhibition. The objective here was to enhance antimicrobial efficacy by excess base neutralization, using phosphoric or hydrochloric acid, and by using surfactants. Methods QPEI NP variants were prepared (i) under controlled neutralization of acid, using NaHCO3, (ii) under controlled carbonate ion neutralization with HCl or H3PO4 and (iii) by treatment with N-lauroylsarcosine or glycerol monostearate. NPs incorporated in the dental materials were examined for their antibacterial effect against Enterococcus faecalis. Results Controlled addition of NaHCO3 resulted in modified QPEI NPs with an increased ability to inhibit bacterial growth. Surface treatment with N-lauroylsarcosine resulted in enhanced antibacterial activity at 0.5% wt/wt concentration in acrylate and epoxy resin-based dental materials. Conclusions The antimicrobial efficacy of QPEI NP may be improved significantly by controlling the addition of NaHCO3, neutralization of excess base and the surface-agent effect.","PeriodicalId":51074,"journal":{"name":"Journal of Applied Biomaterials & Biomechanics","volume":"29 1","pages":"205 - 211"},"PeriodicalIF":0.0,"publicationDate":"2016-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5301/jabfm.5000269","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70592014","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Background The amniotic membrane is a favorable biomaterial to apply in the field of tissue engineering because of its unique biological properties. Human amniotic membranes consist of 2-layered sheets containing numerous growth factors, cytokines and other bioactive substances. Methods In this study, we explored the potential of amnion membrane extracts (AME) and amnion/chorion membrane extracts (A/CME) to promote osteogenic differentiation of osteoblast-like (MG-63) cells. MG-63 cells were cultured in osteogenic induction medium (OIM) with or without 100 µg/mL of AME or A/CME. To determine the early and late differentiation of osteogenesis, alkaline phosphatase (ALP) activity and calcium deposition were measured at 3, 7, 10 and 24 days. Expression of specific genes associated with osteogenic differentiation, including osteocalcin (OCN), osteopontin (OPN), runt domain-containing transcription factor (Runx2) and osterix (OSX) was also determined. Results In vitro experiments demonstrated that A/CME increased ALP activity, osteogenic gene expression and mineralization under osteogenic-inducing conditions. Notably, we found that A/CME contained growth factors related to osteogenesis, including fibroblast growth factors and transforming growth factors, which potentially promoted osteogenic differentiation of MG-63 cells to a greater extent than AME. Conclusions These results indicate that A/CME is capable of providing growth factors and other substrates for osteogenic differentiation, which significantly increased the efficacy of osteogenesis in MG-63 cells. Taken together, the results of this study suggest that human A/CME is a promising biomaterial with therapeutic potential in bone regeneration applications.
{"title":"Promotion of Osteogenic Differentiation by Amnion/Chorion Membrane Extracts","authors":"Y. Go, Sung Eun Kim, G. Cho, S. Chae, J. Song","doi":"10.5301/jabfm.5000264","DOIUrl":"https://doi.org/10.5301/jabfm.5000264","url":null,"abstract":"Background The amniotic membrane is a favorable biomaterial to apply in the field of tissue engineering because of its unique biological properties. Human amniotic membranes consist of 2-layered sheets containing numerous growth factors, cytokines and other bioactive substances. Methods In this study, we explored the potential of amnion membrane extracts (AME) and amnion/chorion membrane extracts (A/CME) to promote osteogenic differentiation of osteoblast-like (MG-63) cells. MG-63 cells were cultured in osteogenic induction medium (OIM) with or without 100 µg/mL of AME or A/CME. To determine the early and late differentiation of osteogenesis, alkaline phosphatase (ALP) activity and calcium deposition were measured at 3, 7, 10 and 24 days. Expression of specific genes associated with osteogenic differentiation, including osteocalcin (OCN), osteopontin (OPN), runt domain-containing transcription factor (Runx2) and osterix (OSX) was also determined. Results In vitro experiments demonstrated that A/CME increased ALP activity, osteogenic gene expression and mineralization under osteogenic-inducing conditions. Notably, we found that A/CME contained growth factors related to osteogenesis, including fibroblast growth factors and transforming growth factors, which potentially promoted osteogenic differentiation of MG-63 cells to a greater extent than AME. Conclusions These results indicate that A/CME is capable of providing growth factors and other substrates for osteogenic differentiation, which significantly increased the efficacy of osteogenesis in MG-63 cells. Taken together, the results of this study suggest that human A/CME is a promising biomaterial with therapeutic potential in bone regeneration applications.","PeriodicalId":51074,"journal":{"name":"Journal of Applied Biomaterials & Biomechanics","volume":"26 1","pages":"171 - 180"},"PeriodicalIF":0.0,"publicationDate":"2016-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5301/jabfm.5000264","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70592117","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Riccardo Beltrami, M. Chiesa, A. Scribante, J. Allegretti, C. Poggio
Background The purpose of this study was to evaluate the effect of surface pretreatment with 37% phosphoric acid on the enamel bond strength of different universal adhesives. Methods One hundred and sixty bovine permanent mandibular incisors freshly extracted were used as a substitute for human teeth. The materials tested in this study included 6 universal adhesives, and 2 self-etch adhesives as control. The teeth were assigned into 2 groups: In the first group, etching was performed using 37% phosphoric acid for 30 seconds. In the second group, no pretreatment agent was applied. After adhesive application, a nanohybrid composite resin was inserted into the enamel surface by packing the material into cylindrical-shaped plastic matrices. After storing, the specimens were placed in a universal testing machine. The normality of the data was calculated using the Kolmogorov-Smirnov test. Analysis of variance (ANOVA) was applied to determine whether significant differences in debond strength values existed among the various groups. Results Groups with phosphoric acid pretreatment showed significantly higher shear bond strength values than groups with no enamel pretreatment (p<0.001). No significant variation in shear strength values was detected when comparing the different adhesive systems applied onto enamel after orthophosphoric acid application (p>0.05). Conclusions All adhesives provide similar bond strength values when enamel pretreatment is applied even if compositions are different. Bond strength values are lower than promised by manufacturers.
{"title":"Comparison of Shear Bond Strength of Universal Adhesives on Etched and Nonetched Enamel","authors":"Riccardo Beltrami, M. Chiesa, A. Scribante, J. Allegretti, C. Poggio","doi":"10.5301/jabfm.5000261","DOIUrl":"https://doi.org/10.5301/jabfm.5000261","url":null,"abstract":"Background The purpose of this study was to evaluate the effect of surface pretreatment with 37% phosphoric acid on the enamel bond strength of different universal adhesives. Methods One hundred and sixty bovine permanent mandibular incisors freshly extracted were used as a substitute for human teeth. The materials tested in this study included 6 universal adhesives, and 2 self-etch adhesives as control. The teeth were assigned into 2 groups: In the first group, etching was performed using 37% phosphoric acid for 30 seconds. In the second group, no pretreatment agent was applied. After adhesive application, a nanohybrid composite resin was inserted into the enamel surface by packing the material into cylindrical-shaped plastic matrices. After storing, the specimens were placed in a universal testing machine. The normality of the data was calculated using the Kolmogorov-Smirnov test. Analysis of variance (ANOVA) was applied to determine whether significant differences in debond strength values existed among the various groups. Results Groups with phosphoric acid pretreatment showed significantly higher shear bond strength values than groups with no enamel pretreatment (p<0.001). No significant variation in shear strength values was detected when comparing the different adhesive systems applied onto enamel after orthophosphoric acid application (p>0.05). Conclusions All adhesives provide similar bond strength values when enamel pretreatment is applied even if compositions are different. Bond strength values are lower than promised by manufacturers.","PeriodicalId":51074,"journal":{"name":"Journal of Applied Biomaterials & Biomechanics","volume":"14 1","pages":"78 - 83"},"PeriodicalIF":0.0,"publicationDate":"2016-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5301/jabfm.5000261","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70592314","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
G. Accardo, C. Ferone, R. Cioffi, D. Frattini, L. Spiridigliozzi, G. Dell’Agli
Background Gadolinium-doped ceria (GDC) is a promising alternative as a solid electrolyte for intermediate temperature solid oxide fuel cells (ITSOFCs) due to its low operating temperature and its high electrical conductivity. The traditional synthesis processes require extended time for powder preparation. Sol-gel methodology for electrolyte fabrication is more versatile and efficient. Methods In this work, nanocrystalline ceria powders, with 10 and 20 mol% of gadolinium (Ce0.9Gd0.1O1.95 and Ce0.8Gd0.2O1.9) were synthesized by a modified sol-gel technique, featuring a nitrate-fuel exothermic reaction. GDC tablets were prepared from powders and sintered at 1500°C with a dwell time of 3 hours. The sintered pellets’ microstructure (by SEM) and electrical conductivity (by EIS) were evaluated. The powder properties, such as crystalline structure (by XRD), thermal properties (TGA/DTA), particle size and morphology (TEM) and textural properties (BET method) were determined and, in addition, for the first time an accurate chemical structural evolution (FTIR) was studied. Results Sintered GDC0.8 samples exhibited the maximum theoretical density of 97% and an average grain size of 700 nm. The electrical conductivity vs. temperature showed values ranging from 1.9∙10−2 to 5.5∙10−2 S·cm−1 at 600°C and 800°C for GDC with 20 mol% of gadolinium. Conclusions The methodology investigated showed reduced reaction time, a better control of stoichiometry and low cost. Characterization results demonstrated that these materials can be applied in ITSOFCs due to high conductivity, even at 550°C-600°C. The increased conductivity is related to the improved mobility of gadolinium ions in a high-density structure, with nanometric grains.
{"title":"Electrical and Microstructural Characterization of Ceramic Gadolinium-Doped Ceria Electrolytes for ITSOFCs by Sol-Gel Route","authors":"G. Accardo, C. Ferone, R. Cioffi, D. Frattini, L. Spiridigliozzi, G. Dell’Agli","doi":"10.5301/jabfm.5000265","DOIUrl":"https://doi.org/10.5301/jabfm.5000265","url":null,"abstract":"Background Gadolinium-doped ceria (GDC) is a promising alternative as a solid electrolyte for intermediate temperature solid oxide fuel cells (ITSOFCs) due to its low operating temperature and its high electrical conductivity. The traditional synthesis processes require extended time for powder preparation. Sol-gel methodology for electrolyte fabrication is more versatile and efficient. Methods In this work, nanocrystalline ceria powders, with 10 and 20 mol% of gadolinium (Ce0.9Gd0.1O1.95 and Ce0.8Gd0.2O1.9) were synthesized by a modified sol-gel technique, featuring a nitrate-fuel exothermic reaction. GDC tablets were prepared from powders and sintered at 1500°C with a dwell time of 3 hours. The sintered pellets’ microstructure (by SEM) and electrical conductivity (by EIS) were evaluated. The powder properties, such as crystalline structure (by XRD), thermal properties (TGA/DTA), particle size and morphology (TEM) and textural properties (BET method) were determined and, in addition, for the first time an accurate chemical structural evolution (FTIR) was studied. Results Sintered GDC0.8 samples exhibited the maximum theoretical density of 97% and an average grain size of 700 nm. The electrical conductivity vs. temperature showed values ranging from 1.9∙10−2 to 5.5∙10−2 S·cm−1 at 600°C and 800°C for GDC with 20 mol% of gadolinium. Conclusions The methodology investigated showed reduced reaction time, a better control of stoichiometry and low cost. Characterization results demonstrated that these materials can be applied in ITSOFCs due to high conductivity, even at 550°C-600°C. The increased conductivity is related to the improved mobility of gadolinium ions in a high-density structure, with nanometric grains.","PeriodicalId":51074,"journal":{"name":"Journal of Applied Biomaterials & Biomechanics","volume":"14 1","pages":"35 - 41"},"PeriodicalIF":0.0,"publicationDate":"2016-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5301/jabfm.5000265","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70592196","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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