The Experts below are selected from a list of 945 Experts worldwide ranked by ideXlab platform
Aleksandra Radtke - One of the best experts on this subject based on the ideXlab platform.
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Assessment of Titanate Nanolayers in Terms of Their Physicochemical and Biological Properties
Materials (Basel Switzerland), 2021Co-Authors: Michalina Ehlert, Aleksandra Radtke, Katarzyna Roszek, Tomasz Jędrzejewski, Piotr PiszczekAbstract:The surface modification of titanium substrates and its alloys in order to improve their osseointegration properties is one of widely studied issues related to the design and production of modern orthopedic and dental implants. In this paper, we discuss the results concerning Ti6Al4V substrate surface modification by (a) alkaline treatment with a 7 M NaOH solution, and (b) production of a porous coating (anodic oxidation with the use of potential U = 5 V) and then treating its surface in the abovementioned alkaline solution. We compared the apatite-forming ability of unmodified and surface-modified titanium alloy in simulated body fluid (SBF) for 1–4 weeks. Analysis of the X-ray diffraction patterns of synthesized coatings allowed their structure characterization before and after immersing in SBF. The obtained nanolayers were studied using Raman spectroscopy, diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), and scanning electron microscopy (SEM) images. Elemental analysis was carried out using X-ray energy dispersion spectroscopy (SEM EDX). Wettability and Biointegration activity (on the basis of the degree of integration of MG-63 osteoblast-like cells, L929 fibroblasts, and adipose-derived mesenchymal stem cells cultured in vitro on the sample surface) were also evaluated. The obtained results proved that the surfaces of Ti6Al4V and Ti6Al4V covered by TiO2 nanoporous coatings, which were modified by titanate layers, promote apatite formation in the environment of body fluids and possess optimal Biointegration properties for fibroblasts and osteoblasts.
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Titania Nanofiber Scaffolds with Enhanced Biointegration Activity—Preliminary In Vitro Studies
International journal of molecular sciences, 2019Co-Authors: Michalina Ehlert, Katarzyna Roszek, Tomasz Jędrzejewski, Michał Bartmański, Aleksandra RadtkeAbstract:The increasing need for novel bone replacement materials has been driving numerous studies on modifying their surface to stimulate osteogenic cells expansion and to accelerate bone tissue regeneration. The goal of the presented study was to optimize the production of titania-based bioactive materials with high porosity and defined nanostructure, which supports the cell viability and growth. We have chosen to our experiments TiO2 nanofibers, produced by chemical oxidation of Ti6Al4V alloy. Fibrous nanocoatings were characterized structurally (X-ray diffraction (XRD)) and morphologically (scanning electron microscopy (SEM)). The wettability of the coatings and their mechanical properties were also evaluated. We have investigated the direct influence of the modified titanium alloy surfaces on the survival and proliferation of mesenchymal stem cells derived from adipose tissue (ADSCs). In parallel, proliferation of bone tissue cells—human osteoblasts MG-63 and connective tissue cells - mouse fibroblasts L929, as well as cell viability in co-cultures (osteoblasts/ADSCs and fibroblasts/ADSCs has been studied. The results of our experiments proved that among all tested nanofibrous coatings, the amorphous titania-based ones were the most optimal scaffolds for the integration and proliferation of ADSCs, fibroblasts, and osteoblasts. Thus, we postulated these scaffolds to have the osteopromotional potential. However, from the co-culture experiments it can be concluded that ADSCs have the ability to functionalize the initially unfavorable surface, and make it suitable for more specialized and demanding cells.
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titania nanofiber scaffolds with enhanced Biointegration activity preliminary in vitro studies
International Journal of Molecular Sciences, 2019Co-Authors: Michalina Ehlert, Katarzyna Roszek, Michał Bartmański, Tomasz Jedrzejewski, Aleksandra RadtkeAbstract:The increasing need for novel bone replacement materials has been driving numerous studies on modifying their surface to stimulate osteogenic cells expansion and to accelerate bone tissue regeneration. The goal of the presented study was to optimize the production of titania-based bioactive materials with high porosity and defined nanostructure, which supports the cell viability and growth. We have chosen to our experiments TiO2 nanofibers, produced by chemical oxidation of Ti6Al4V alloy. Fibrous nanocoatings were characterized structurally (X-ray diffraction (XRD)) and morphologically (scanning electron microscopy (SEM)). The wettability of the coatings and their mechanical properties were also evaluated. We have investigated the direct influence of the modified titanium alloy surfaces on the survival and proliferation of mesenchymal stem cells derived from adipose tissue (ADSCs). In parallel, proliferation of bone tissue cells—human osteoblasts MG-63 and connective tissue cells - mouse fibroblasts L929, as well as cell viability in co-cultures (osteoblasts/ADSCs and fibroblasts/ADSCs has been studied. The results of our experiments proved that among all tested nanofibrous coatings, the amorphous titania-based ones were the most optimal scaffolds for the integration and proliferation of ADSCs, fibroblasts, and osteoblasts. Thus, we postulated these scaffolds to have the osteopromotional potential. However, from the co-culture experiments it can be concluded that ADSCs have the ability to functionalize the initially unfavorable surface, and make it suitable for more specialized and demanding cells.
Daniel S Kohane - One of the best experts on this subject based on the ideXlab platform.
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New improvements in Boston Keratoprosthesis (KPro): titanium surface modifications
Acta Ophthalmologica, 2012Co-Authors: B Salvador Culla, Kj Jeong, Ei Paschalis, Hh Chiang, Ik Gipson, C. H. Dohlman, Daniel S KohaneAbstract:Purpose Improve Biointegration and esthetics of Boston KPro through Ti coating. Methods Polydopamine (PDA) was used to form a Ti oxide (TiO2) film on polymethylmethacrylate (PMMA) rods through liquid phase deposition. The rods were inserted in porcine corneas and kept in culture for two weeks. Biointegration was assessed by measuring the force required to pull the rods out of the corneas with an Instron 5542 tensiometer, followed by SEM examination of their surface. Color modification (blue or brown) of Ti backplates of the Boston KPro was achieved using oxide formation in an anodization setup, and biocompatibility was studied using human corneal limbal epithelial cells. Results Mechanical pull-out showed that TiO2 significantly increased the force required to separate the rods from the corneas (0.354 N), compared to bare PMMA (0.039 N) and PDA (0.098 N). SEM images showed residual cellular and extracellular materials only on TiO2-coated rods. Ti oxidation produced blue or brown-coated backplates. No difference was observed in proliferation, migration or cytotoxicity between coated and uncoated groups in cell culture (p>0.745). Conclusion TiO2 coating enhanced corneal tissue integration with PMMA rods. Oxidation also improved the esthetics of the Ti backplates of the Boston KPro, without compromising its safety or biocompatibility.
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Hydroxyapatite for Keratoprosthesis Biointegration
Investigative ophthalmology & visual science, 2011Co-Authors: Liqiang Wang, Kyung Jae Jeong, Claes H Dohlman, James Chodosh, Homer H. Chiang, David Zurakowski, Irmgard Behlau, Robert Langer, Daniel S KohaneAbstract:According to the World Health Organization, corneal disease accounted for 8 million cases of blindness in 2009.1 Corneal allograft surgery is often successful in such cases, but in some patients and conditions the success rate is low. In a large outcome study, only 20% of regrafts remained clear for 5 years2; more recent reports have confirmed this trend.3,4 With repeated allograft failure, few treatments are available, and tissue-engineered corneas are not yet suitable for clinical use. Corneal prostheses (keratoprosthesis; KPro) are the only viable option for restoring sight. There are several KPros on the global market that vary in terms of indications, surgical complexity regarding placement, and outcomes. The primary material used in the optic axis of many devices is polymethylmethacrylate (PMMA) because of its transparency, high mechanical strength, ease of processing, and low cost. Firm bonding of any KPro to the surrounding cornea is clinically critical; it is the main challenge in the development of most keratoprostheses. For example, in the case of the Boston KPro, which is relatively simple to construct and implant and which continues to have improved outcomes and expanded indications thanks to design enhancements and optimized postoperative management,5,6 the poor adhesion of PMMA to the surrounding tissue creates opportunities for bacteria to enter the eye, resulting in infection, leakage of aqueous humor, and even extrusion of the implant.7,8 Hydroxyapatite (HAp) is a main component of bone and teeth and has been widely used for surface modification of bone implants9 because it can bind electrostatically with charged biological molecules.10,11 HAp induces a relatively limited inflammatory and foreign body response12 and supports the adhesion and growth of human keratocytes (corneal fibroblasts) better than glass, polytetrafluoroethylene, and polyhydroxymethacrylate in vitro.13 These properties make it a desirable material for use in a KPro. However, the poor mechanical properties of bulk HAp ceramics make them challenging to work with. Here we have developed or adapted a variety of related approaches to coating PMMA with HAp and assessed their effectiveness in enhancing integration with the cornea. HAp coating can be achieved through biomineralization using simulated body fluid (SBF).14–16 Deposition on PMMA can be enhanced by treatment with highly concentrated sodium hydroxide (NaOH), which produces negatively charged carboxyl groups on the surface.17 Coating with polydopamine, which can form on a wide range of surfaces,18 can also induce HAp deposition on various substrates in SBF.19 We have hypothesized that further coating the polydopamine-modified PMMA discs with 11-mercaptoundecanoic acid (11-MUA) would enhance apatite deposition. The carboxyl groups of 11-MUA can act as nucleation sites for Ca/P deposition.20 We have characterized these HAp-coated PMMAs in vitro, alone and in the presence of corneal fibroblasts. In addition to the cell-based experiments commonly performed in studies of Biointegration, we have used a custom-made 3D printed device to determine whether coating with HAp improves the mechanical strength of the tissue interaction ex vivo. Finally, we studied the effect of coating with HAp on biocompatibility in vivo.
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Polydopamine coatings enhance Biointegration of a model polymeric implant
Soft Matter, 2011Co-Authors: Kyung Jae Jeong, Cristina F. Stefanescu, Julia Polat, Michael W Lawlor, Claes H Dohlman, Robert S. Langer, Liqiang Wang, Daniel S KohaneAbstract:The Biointegration of implants affects their function{,} stability and safety. Although most research on this topic has focused on bone and other hard tissues{,} Biointegration with soft tissues is important in numerous applications{,} such as in prosthetic corneas. Here{,} we have adapted polydopamine-based adhesive surface chemistry to enhance the Biointegration with soft tissue of a model polymer-poly(methyl methacrylate) (PMMA){,} commonly used in prosthetic corneas. Polydopamine coating (PDA) and subsequent modification with the cell-adhesive peptide RGD (PDA-PEG-RGD) significantly enhanced cellular proliferation of corneal epithelial cells and keratocytes without causing excessive secretion of pro-inflammatory cytokines (e.g.IL-6) by either cell type. PDA adhered tightly to collagen gels{,} while PDA-PEG-RGD and uncoated PMMA did not. PDA{'}s adhesion to collagen was greatly reduced by preincubation in serum. Tissue reaction to both polydopamine-coated surfaces was benign after 45 days of subcutaneous implantation. However{,} in contrast to the findings with collagen gels{,} PDA-PEG-RGD bound much more tightly to tissue than did PDA-although both bound better than unmodified PMMA. Polydopamine-based surface chemistries are potentially useful in enhancing tissue integration of implants with soft tissues.
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Surface modification and drug delivery for Biointegration
Therapeutic delivery, 2011Co-Authors: Kyung Jae Jeong, Daniel S KohaneAbstract:Biointegration refers to the interconnection between a biomedical device and the recipient tissue. In many implant devices, the lack of proper Biointegration can cause device failure and potentially serious medical problems. This review summarizes the recent progress in surface chemistry, drug delivery and antifouling methods to improve the Biointegration of implants. Much progress has been made as our understanding of biological systems and material properties expands and as new technologies become available. This article addresses methods of enhancing Biointegration by means of modifying implant surface chemistry and by drug-delivery approaches.
Walter L. Siqueira - One of the best experts on this subject based on the ideXlab platform.
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Evaluating protein binding specificity of titanium surfaces through mass spectrometry-based proteomics.
Clinical oral investigations, 2020Co-Authors: David Zuanazzi, Yizhi Xiao, Walter L. SiqueiraAbstract:To evaluate whether surface characteristics of different titanium modifications may influence the composition of the salivary pellicle on each surface by analyzing the salivary proteome through mass spectrometry–based proteomics. Titanium discs with three surfaces modifications (PT (machined titanium), SLA (sandblasted/large-grit/acid-etched), and SLActive (modified SLA)) were characterized (topography, chemistry, and energy) prior to being exposed to saliva for 2 h to form a protein pellicle. The resultant protein layer was retrieved and analyzed through mass spectrometry (nLC-ESI-MS/MS) to examine the surface specificity for protein binding, while the proteome profile of each surface was classified. The proteome analysis showed that the salivary pellicle composition was more complex on rough surfaces (SLA and SLActive). Although variability in protein composition was observed between surfaces, most proteins were detected on more than one surface, indicating a limited surface specificity for protein binding. Additionally, the salivary pellicle formed on the SLActive presented a larger number of proteins associated with immune response, biological adhesion, and biomineralization. Although topography, chemistry, and energy differed between the surfaces, they were not determinant to produce a salivary pellicle with high surface specificity. Also, we showed that several salivary proteins adsorbed on Ti surfaces are involved in biological functions important to the Biointegration. This study sheds light on the necessity for the development of bioactive surfaces that favors the formation of a specific protein layer that can enhance tissue response to assist the Biointegration of dental implants.
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Evaluating protein binding specificity of titanium surfaces through mass spectrometry–based proteomics
Clinical Oral Investigations, 2020Co-Authors: David Zuanazzi, Yizhi Xiao, Walter L. SiqueiraAbstract:Objectives To evaluate whether surface characteristics of different titanium modifications may influence the composition of the salivary pellicle on each surface by analyzing the salivary proteome through mass spectrometry–based proteomics. Materials and methods Titanium discs with three surfaces modifications (PT (machined titanium), SLA (sandblasted/large-grit/acid-etched), and SLActive (modified SLA)) were characterized (topography, chemistry, and energy) prior to being exposed to saliva for 2 h to form a protein pellicle. The resultant protein layer was retrieved and analyzed through mass spectrometry (nLC-ESI-MS/MS) to examine the surface specificity for protein binding, while the proteome profile of each surface was classified. Results The proteome analysis showed that the salivary pellicle composition was more complex on rough surfaces (SLA and SLActive). Although variability in protein composition was observed between surfaces, most proteins were detected on more than one surface, indicating a limited surface specificity for protein binding. Additionally, the salivary pellicle formed on the SLActive presented a larger number of proteins associated with immune response, biological adhesion, and biomineralization. Conclusions Although topography, chemistry, and energy differed between the surfaces, they were not determinant to produce a salivary pellicle with high surface specificity. Also, we showed that several salivary proteins adsorbed on Ti surfaces are involved in biological functions important to the Biointegration. Clinical relevance This study sheds light on the necessity for the development of bioactive surfaces that favors the formation of a specific protein layer that can enhance tissue response to assist the Biointegration of dental implants.
Michalina Ehlert - One of the best experts on this subject based on the ideXlab platform.
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Assessment of Titanate Nanolayers in Terms of Their Physicochemical and Biological Properties
Materials (Basel Switzerland), 2021Co-Authors: Michalina Ehlert, Aleksandra Radtke, Katarzyna Roszek, Tomasz Jędrzejewski, Piotr PiszczekAbstract:The surface modification of titanium substrates and its alloys in order to improve their osseointegration properties is one of widely studied issues related to the design and production of modern orthopedic and dental implants. In this paper, we discuss the results concerning Ti6Al4V substrate surface modification by (a) alkaline treatment with a 7 M NaOH solution, and (b) production of a porous coating (anodic oxidation with the use of potential U = 5 V) and then treating its surface in the abovementioned alkaline solution. We compared the apatite-forming ability of unmodified and surface-modified titanium alloy in simulated body fluid (SBF) for 1–4 weeks. Analysis of the X-ray diffraction patterns of synthesized coatings allowed their structure characterization before and after immersing in SBF. The obtained nanolayers were studied using Raman spectroscopy, diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), and scanning electron microscopy (SEM) images. Elemental analysis was carried out using X-ray energy dispersion spectroscopy (SEM EDX). Wettability and Biointegration activity (on the basis of the degree of integration of MG-63 osteoblast-like cells, L929 fibroblasts, and adipose-derived mesenchymal stem cells cultured in vitro on the sample surface) were also evaluated. The obtained results proved that the surfaces of Ti6Al4V and Ti6Al4V covered by TiO2 nanoporous coatings, which were modified by titanate layers, promote apatite formation in the environment of body fluids and possess optimal Biointegration properties for fibroblasts and osteoblasts.
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Titania Nanofiber Scaffolds with Enhanced Biointegration Activity—Preliminary In Vitro Studies
International journal of molecular sciences, 2019Co-Authors: Michalina Ehlert, Katarzyna Roszek, Tomasz Jędrzejewski, Michał Bartmański, Aleksandra RadtkeAbstract:The increasing need for novel bone replacement materials has been driving numerous studies on modifying their surface to stimulate osteogenic cells expansion and to accelerate bone tissue regeneration. The goal of the presented study was to optimize the production of titania-based bioactive materials with high porosity and defined nanostructure, which supports the cell viability and growth. We have chosen to our experiments TiO2 nanofibers, produced by chemical oxidation of Ti6Al4V alloy. Fibrous nanocoatings were characterized structurally (X-ray diffraction (XRD)) and morphologically (scanning electron microscopy (SEM)). The wettability of the coatings and their mechanical properties were also evaluated. We have investigated the direct influence of the modified titanium alloy surfaces on the survival and proliferation of mesenchymal stem cells derived from adipose tissue (ADSCs). In parallel, proliferation of bone tissue cells—human osteoblasts MG-63 and connective tissue cells - mouse fibroblasts L929, as well as cell viability in co-cultures (osteoblasts/ADSCs and fibroblasts/ADSCs has been studied. The results of our experiments proved that among all tested nanofibrous coatings, the amorphous titania-based ones were the most optimal scaffolds for the integration and proliferation of ADSCs, fibroblasts, and osteoblasts. Thus, we postulated these scaffolds to have the osteopromotional potential. However, from the co-culture experiments it can be concluded that ADSCs have the ability to functionalize the initially unfavorable surface, and make it suitable for more specialized and demanding cells.
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titania nanofiber scaffolds with enhanced Biointegration activity preliminary in vitro studies
International Journal of Molecular Sciences, 2019Co-Authors: Michalina Ehlert, Katarzyna Roszek, Michał Bartmański, Tomasz Jedrzejewski, Aleksandra RadtkeAbstract:The increasing need for novel bone replacement materials has been driving numerous studies on modifying their surface to stimulate osteogenic cells expansion and to accelerate bone tissue regeneration. The goal of the presented study was to optimize the production of titania-based bioactive materials with high porosity and defined nanostructure, which supports the cell viability and growth. We have chosen to our experiments TiO2 nanofibers, produced by chemical oxidation of Ti6Al4V alloy. Fibrous nanocoatings were characterized structurally (X-ray diffraction (XRD)) and morphologically (scanning electron microscopy (SEM)). The wettability of the coatings and their mechanical properties were also evaluated. We have investigated the direct influence of the modified titanium alloy surfaces on the survival and proliferation of mesenchymal stem cells derived from adipose tissue (ADSCs). In parallel, proliferation of bone tissue cells—human osteoblasts MG-63 and connective tissue cells - mouse fibroblasts L929, as well as cell viability in co-cultures (osteoblasts/ADSCs and fibroblasts/ADSCs has been studied. The results of our experiments proved that among all tested nanofibrous coatings, the amorphous titania-based ones were the most optimal scaffolds for the integration and proliferation of ADSCs, fibroblasts, and osteoblasts. Thus, we postulated these scaffolds to have the osteopromotional potential. However, from the co-culture experiments it can be concluded that ADSCs have the ability to functionalize the initially unfavorable surface, and make it suitable for more specialized and demanding cells.
Yong Han - One of the best experts on this subject based on the ideXlab platform.
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Magnetic Silicium Hydroxyapatite Nanorods for Enhancing Osteoblast Response in Vitro and Biointegration in Vivo.
ACS biomaterials science & engineering, 2019Co-Authors: Fang Dai, Ting Yan, Yang Xue, Lan Zhang, Yong HanAbstract:Osteoblast behavior playing an important role in the Biointegration of the Ti implant with host bone in vivo can be regulated by surface properties and magnetic field. In order to endow the Ti surface with good osteogenesis activity, Si monosubstituted and Fe and Si cosubstituted hydroxyapatite (HAp) nanorods were fabricated on microporous TiO2 by microarc oxidation (MAO) followed with hydrothermal treatment (HT). The surface properties including microstructure, microroughness, hydrophilicity, ion release, magnetic property, cytocompatibility, and Biointegration of substituted HAp nanorods were observed and evaluated, together with pure HAp nanorods and microarc oxidated (MAOed) TiO2 as controls. After being doped with Fe, MAOed TiO2 has no changes in phase composition and microroughness, whereas it displays weakly ferromagnetic behavior and can enhance osteoblast differentiation in vitro and formation of new bone in vivo, compared with the undoped one. The substituted HAp nanorods adhere firmly to TiO2 and have almost the same wettability and microroughness but additional Si, Fe, and/or Ca released into the medium, compared with pure HAp nanorods. Moreover, the cosubstituted HAp has a small ferromagnetic signal, while its saturation magnetization value is less than that of the MAOed doped with Fe. Compared to pure HA nanorods, the substituted HAp nanorods not only improve cell proliferation and differentiation in vitro, but also enhance the ability of bone integration in vivo, especially for the cosubstituted one, which should be ascribed to the combined effect of microstructure, magnetic property, and released ions.
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Magnetic Silicium Hydroxyapatite Nanorods for Enhancing Osteoblast Response in Vitro and Biointegration in Vivo
2019Co-Authors: Fang Dai, Ting Yan, Yang Xue, Lan Zhang, Yong HanAbstract:Osteoblast behavior playing an important role in the Biointegration of the Ti implant with host bone in vivo can be regulated by surface properties and magnetic field. In order to endow the Ti surface with good osteogenesis activity, Si monosubstituted and Fe and Si cosubstituted hydroxyapatite (HAp) nanorods were fabricated on microporous TiO2 by microarc oxidation (MAO) followed with hydrothermal treatment (HT). The surface properties including microstructure, microroughness, hydrophilicity, ion release, magnetic property, cytocompatibility, and Biointegration of substituted HAp nanorods were observed and evaluated, together with pure HAp nanorods and microarc oxidated (MAOed) TiO2 as controls. After being doped with Fe, MAOed TiO2 has no changes in phase composition and microroughness, whereas it displays weakly ferromagnetic behavior and can enhance osteoblast differentiation in vitro and formation of new bone in vivo, compared with the undoped one. The substituted HAp nanorods adhere firmly to TiO2 and have almost the same wettability and microroughness but additional Si, Fe, and/or Ca released into the medium, compared with pure HAp nanorods. Moreover, the cosubstituted HAp has a small ferromagnetic signal, while its saturation magnetization value is less than that of the MAOed doped with Fe. Compared to pure HA nanorods, the substituted HAp nanorods not only improve cell proliferation and differentiation in vitro, but also enhance the ability of bone integration in vivo, especially for the cosubstituted one, which should be ascribed to the combined effect of microstructure, magnetic property, and released ions