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R D K Misra - One of the best experts on this subject based on the ideXlab platform.
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degradation mechanism and increased stability of Chitosan based hybrid scaffolds cross linked with nanostructured carbon process structure functional property relationship
Polymer Degradation and Stability, 2013Co-Authors: Dilip Depan, J.s. Shah, R D K MisraAbstract:Abstract The degradation behavior of porous scaffolds plays an important role in the synthesis of new tissue. In this study, three-dimensional hybrid porous scaffolds of Chitosan (CS) comprised of nanostructured carbon (graphene oxide (GO) and single-walled carbon nanohorns (SWCNH)) were prepared by freeze-drying method. In-vitro degradation behavior of scaffolds was investigated up to 8 weeks in phosphate buffer saline (PBS) solution at 37 °C. The characteristics of scaffolds explored as a function of degradation time include crystalline structure, pore morphology, molecular weight, and wet/dry weight. The pH value of the PBS solution during degradation was also monitored. The study demonstrates for the first time that hybrid Chitosan scaffolds with nanostructured carbon (GO and SWCNH) are potentially more stable than Pure Chitosan scaffolds during the time period required for tissue regeneration. The stability of hybrid scaffolds is attributed to nanostructured carbon that was processed with the objective that it is present in a robust manner via a highly cross-linked dense network structure. The chemical structure of Chitosan was disrupted within a short period of two weeks, while disruption occurred in hybrid scaffolds after eight weeks. This was accompanied by a weight loss of ∼28% in Pure Chitosan and ∼20% in hybrid scaffolds. Furthermore, the degraded products were of low molecular weight in Pure Chitosan and high molecular weight in hybrid Chitosan scaffolds. This led to significant decrease in the pH of solution to ∼6.2 in Pure Chitosan and to ∼7.2 in hybrid scaffolds. The observations clearly underscore that the introduction of GO and SWCNH via cross-link mechanism in CS is a potentially viable approach to tune the degradation rate of hybrid scaffolds in tissue engineering.
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organic inorganic hybrid network structure nanocomposite scaffolds based on grafted Chitosan for tissue engineering
Acta Biomaterialia, 2011Co-Authors: Dilip Depan, P Venkata K C Surya, B Girase, R D K MisraAbstract:Abstract We describe the first study of structure–processing–property relationship in organic/inorganic hybrid network structure nanocomposite scaffolds based on grafted Chitosan for bone tissue engineering. Chitosan was first grafted with propylene oxide to form hydroxypropylated Chitosan, which was subsequently linked with ethylene glycol functionalized nanohydroxyapatite to form an organic/inorganic network structure. The resulting scaffold was characterized by a highly porous structure and significantly superior physico-chemical, mechanical and biological properties compared to Pure Chitosan. The scaffolds exhibited high modulus, controlled swelling behavior and reduced water uptake, but the water retention ability was similar to Pure Chitosan scaffold. MTT assay studies confirmed the non-cytotoxic nature of the scaffolds and enabled degradation products to be analyzed. The nanocomposite scaffolds were biocompatible and supported adhesion, spreading, proliferation and viability of osteoblasts cells. Furthermore, the cells were able to infiltrate and colonize into the pores of the scaffolds and establish cell–cell interactions. The study suggests that hydroxypropylation of Chitosan and forming a network structure with a nano-inorganic constituent is a promising approach for enhancing physico-chemical, functional and biological properties for utilization in bone tissue engineering applications.
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controlled and extended drug release behavior of Chitosan based nanoparticle carrier
Acta Biomaterialia, 2010Co-Authors: Q. Yuan, San Hein, J.s. Shah, R D K MisraAbstract:Abstract Controlled drug release is presently gaining significant attention. In this regard, we describe here the synthesis (based on the understanding of chemical structure), structural morphology, swelling behavior and drug release response of Chitosan intercalated in an expandable layered aluminosilicate. In contrast to Pure Chitosan, for which there is a continuous increase in drug release with time, the Chitosan–aluminosilicate nanocomposite carrier was characterized by controlled and extended release. Drug release from the nanocomposite particle carrier occurred by degradation of the carrier to its individual components or nanostructures with a different composition. In both the layered aluminosilicate-based mineral and Chitosan–aluminosilicate nanocomposite carriers the positively charged chemotherapeutic drug strongly bound to the negatively charged aluminosilicate and release of the drug was slow. Furthermore, the pattern of drug release from the Chitosan–aluminosilicate nanocomposite carrier was affected by pH and the Chitosan/aluminosilicate ratio. The study points to the potential application of this hybrid nanocomposite carrier in biomedical applications, including tissue engineering and controlled drug delivery.
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biomimetic Chitosan nanohydroxyapatite composite scaffolds for bone tissue engineering
Acta Biomaterialia, 2009Co-Authors: Wahwah Theinhan, R D K MisraAbstract:Abstract We describe a comparative assessment of the structure–property–process relationship of three-dimensional Chitosan–nanohydroxyapatite (nHA) and Pure Chitosan scaffolds in conjunction with their respective biological response with the aim of advancing our insight into aspects that concern bone tissue engineering. High- and medium-molecular-weight (MW) Chitosan scaffolds with 0.5, 1 and 2 wt.% fraction of nHA were fabricated by freezing and lyophilization. The nanocomposites were characterized by a highly porous structure and the pore size (∼50 to 120 μm) was in a similar range for the scaffolds with different content of nHA. A combination of X-ray diffraction, Fourier transform infrared spectroscopy and electron microscopy indicated that nHA particles were uniformly dispersed in Chitosan matrix and there was a chemical interaction between Chitosan and nHA. The compression modulus of hydrated Chitosan scaffolds was increased on the addition of 1 wt.% nHA from 6.0 to 9.2 kPa in high-MW scaffold. The water uptake ability of composites decreased with an increase in the amount of nHA, while the water retention ability was similar to Pure Chitosan scaffold. After 28 days in physiological condition, nanocomposites indicated about 10% lower degree of degradation in comparison to Chitosan scaffold. The biological response of pre-osteoblasts (MC 3T3-E1) on nanocomposite scaffolds was superior in terms of improved cell attachment, higher proliferation, and well-spread morphology in relation to Chitosan scaffold. In composite scaffolds, cell proliferation was about 1.5 times greater than Pure Chitosan after 7 days of culture and beyond, as implied by qualitative analysis via fluorescence microscopy and quantitative study through MTT assay. The observations related to well-developed structure morphology, physicochemical properties and superior cytocompatibility suggest that Chitosan–nHA porous scaffolds are potential candidate materials for bone regeneration although it is necessary to further enhance the mechanical properties of the nanocomposite.
Miqin Zhang - One of the best experts on this subject based on the ideXlab platform.
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Chitosan alginate as scaffolding material for cartilage tissue engineering
Journal of Biomedical Materials Research Part A, 2005Co-Authors: Zhensheng Li, Miqin ZhangAbstract:Tissue compatibility of Chitosan–alginate scaffolds was studied in vitro in terms of cell morphology, proliferation, and functionality using HTB-94 cells. The scaffold has an interconnected 3D porous structure, and was fabricated by thermally induced phase separation followed by freeze drying. Cell proliferation on the Chitosan–alginate scaffold was found to be faster than on a Pure Chitosan scaffold. After cell culture for 2 weeks in vitro, the cells on the Chitosan scaffold gradually assumed a fibroblast-like morphology while the cells on the Chitosan–alginate scaffold retained their spherical morphology throughout the period of study. SDS-PAGE electrophoresis and Western blot assays for proteins extracted from cells grown on scaffolds indicated that production of cartilage-specific collagen type II, a marker for chondrocytic phenotype, increased from week 2 to week 3 on the Chitosan–alginate scaffold but decreased on the Chitosan scaffold. This study suggested that Chitosan–alginate scaffolds promote cell proliferation, enhance phenotype expression of HTB-94 chondrocytes, and may potentially serve as an improved alternative to Chitosan scaffolds for cartilage tissue engineering. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
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Chitosan-alginate as scaffolding material for cartilage tissue engineering
Journal of Biomedical Materials Research - Part A, 2005Co-Authors: Zhensheng Li, Miqin ZhangAbstract:Tissue compatibility of Chitosan-alginate scaffolds was studied in vitro in terms of cell morphology, proliferation, and functionality using HTB-94 cells. The scaffold has an interconnected 3D porous structure, and was fabricated by thermally induced phase separation followed by freeze drying. Cell proliferation on the Chitosan-alginate scaffold was found to be faster than on a Pure Chitosan scaffold. After cell culture for 2 weeks in vitro, the cells on the Chitosan scaffold gradually assumed a fibroblast-like morphology while the cells on the Chitosan-alginate scaffold retained their spherical morphology throughout the period of study. SDS-PAGE electrophoresis and Western blot assays for proteins extracted from cells grown on scaffolds indicated that production of cartilage-specific collagen type II, a marker for chondrocytic phenotype, increased from week 2 to week 3 on the Chitosan-alginate scaffold but decreased on the Chitosan scaffold. This study suggested that Chitosan-alginate scaffolds promote cell proliferation, enhance phenotype expression of HTB-94 chondrocytes, and may potentially serve as an improved alternative to Chitosan scaffolds for cartilage tissue engineering.
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calcium phosphate Chitosan composite scaffolds for controlled in vitro antibiotic drug release
Journal of Biomedical Materials Research, 2002Co-Authors: Yong Zhang, Miqin ZhangAbstract:Macroporous Chitosan scaffolds reinforced by β-tricalcium phosphate (β-TCP) and calcium phosphate invert glasses were fabricated using a thermally induced phase separation technique. These porous composite materials were specially designed as both a drug carrier for controlled drug release and a scaffold for bone regeneration. The controlled drug release of antibiotic gentamicin-sulfate (GS) loaded scaffolds and morphology of osteosarcoma MG63 cells cultured on the scaffolds were studied. In comparison with the GS loaded Pure Chitosan scaffolds, the initial burst release of GS was decreased through incorporating calcium phosphate crystals and glasses into the scaffolds, and the sustained release for more than 3 weeks was achieved. The possible mechanisms for the controlled drug release were investigated by SEM, FTIR, and measurements of the pH values of the PBS solution during the drug release test. SEM micrographs showed no apparent morphological differences for osteoblastic cells grown on the Pure Chitosan scaffolds and those grown on composite scaffolds. The cells were attached and migrated on these scaffolds, and exhibited a biological appearance, suggesting a good cellular compatibility. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 62: 378–386, 2002
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synthesis and characterization of macroporous Chitosan calcium phosphate composite scaffolds for tissue engineering
Journal of Biomedical Materials Research, 2001Co-Authors: Yong Zhang, Miqin ZhangAbstract:Chitosan scaffolds reinforced by beta-tricalcium phosphate (beta-TCP) and calcium phosphate invert glass were fabricated with a low-cost, bioclean freeze-drying technique via thermally induced phase separation. The microstructure, mechanical performance, biodegradation, and bioactivity of the scaffolds were studied. The composite scaffolds were macroporous, and the pore structures of the scaffolds with beta-TCP and the glass appeared very different. Both the compressive modulus and yield strength of the scaffolds were greatly improved, and reinforced microstructures were achieved. The bioactivity tests showed a continuous decrease in both Ca and P concentrations of a simulated body fluid (SBF) after the scaffolds with beta-TCP were immersed in the SBF for more than 20 h, which suggests that an apatite layer might be formed on the scaffolds. However, the same was not observed for the Pure Chitosan scaffolds or the scaffolds incorporated with the glass. This was further confirmed by micrographs from scanning electron microscopy. This study suggests that the desirable pore structure, biodegradation rate, and bioactivity of the composite scaffolds might be achieved through controlling the ratio of Chitosan and calcium phosphates or beta-TCP and the glass.
Lobat Tayebi - One of the best experts on this subject based on the ideXlab platform.
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mechanical properties of natural Chitosan hydroxyapatite magnetite nanocomposites for tissue engineering applications
Materials Science and Engineering: C, 2016Co-Authors: Fatemeh Heidari, Mehdi Razavi, M E Bahrololoom, Reza Bazarganlari, Daryoosh Vashaee, Hari Kotturi, Lobat TayebiAbstract:Chitosan (CS), hydroxyapatite (HA), and magnetite (Fe3O4) have been broadly employed for bone treatment applications. Having a hybrid biomaterial composed of the aforementioned constituents not only accumulates the useful characteristics of each component, but also provides outstanding composite properties. In the present research, mechanical properties of Pure CS, CS/HA, CS/HA/magnetite, and CS/magnetite were evaluated by the measurements of bending strength, elastic modulus, compressive strength and hardness values. Moreover, the morphology of the bending fracture surfaces were characterized using a scanning electron microscope (SEM) and an image analyzer. Studies were also conducted to examine the biological response of the human Mesenchymal Stem Cells (hMSCs) on different composites. We conclude that, although all of these composites possess in-vitro biocompatibility, adding hydroxyapatite and magnetite to the Chitosan matrix can noticeably enhance the mechanical properties of the Pure Chitosan.
Peter I Lelkes - One of the best experts on this subject based on the ideXlab platform.
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electrospun hydroxyapatite containing Chitosan nanofibers crosslinked with genipin for bone tissue engineering
Biomaterials, 2012Co-Authors: Michael Frohbergh, Anna Katsman, Gregory P Botta, Phillip Lazarovici, Caroline L Schauer, Ulrike G K Wegst, Peter I LelkesAbstract:Abstract Reconstruction of large bone defects remains problematic in orthopedic and craniofacial clinical practice. Autografts are limited in supply and are associated with donor site morbidity while other materials show poor integration with the host's own bone. This lack of integration is often due to the absence of periosteum, the outer layer of bone that contains osteoprogenitor cells and is critical for the growth and remodeling of bone tissue. In this study we developed a one-step platform to electrospin nanofibrous scaffolds from Chitosan, which also contain hydroxyapatite nanoparticles and are crosslinked with genipin. We hypothesized that the resulting composite scaffolds represent a microenvironment that emulates the physical, mineralized structure and mechanical properties of non-weight bearing bone extracellular matrix while promoting osteoblast differentiation and maturation similar to the periosteum. The ultrastructure and physicochemical properties of the scaffolds were studied using scanning electron microscopy and spectroscopic techniques. The average fiber diameters of the electrospun scaffolds were 227 ± 154 nm as spun, and increased to 335 ± 119 nm after crosslinking with genipin. Analysis by X-ray diffraction, Fourier transformed infrared spectroscopy and energy dispersive spectroscopy confirmed the presence of characteristic features of hydroxyapatite in the composite Chitosan fibers. The Young's modulus of the composite fibrous scaffolds was 142 ± 13 MPa, which is similar to that of the natural periosteum. Both Pure Chitosan scaffolds and composite hydroxyapatite-containing Chitosan scaffolds supported adhesion, proliferation and osteogenic differentiation of mouse 7F2 osteoblast-like cells. Expression and enzymatic activity of alkaline phosphatase, an early osteogenic marker, were higher in cells cultured on the composite scaffolds as compared to Pure Chitosan scaffolds, reaching a significant, 2.4 fold, difference by day 14 ( p
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electrospun hydroxyapatite containing Chitosan nanofibers crosslinked with genipin for bone tissue engineering
Biomaterials, 2012Co-Authors: Michael Frohbergh, Anna Katsman, Gregory P Botta, Phillip Lazarovici, Caroline L Schauer, Ulrike G K Wegst, Peter I LelkesAbstract:Reconstruction of large bone defects remains problematic in orthopedic and craniofacial clinical practice. Autografts are limited in supply and are associated with donor site morbidity while other materials show poor integration with the host's own bone. This lack of integration is often due to the absence of periosteum, the outer layer of bone that contains osteoprogenitor cells and is critical for the growth and remodeling of bone tissue. In this study we developed a one-step platform to electrospin nanofibrous scaffolds from Chitosan, which also contain hydroxyapatite nanoparticles and are crosslinked with genipin. We hypothesized that the resulting composite scaffolds represent a microenvironment that emulates the physical, mineralized structure and mechanical properties of non-weight bearing bone extracellular matrix while promoting osteoblast differentiation and maturation similar to the periosteum. The ultrastructure and physicochemical properties of the scaffolds were studied using scanning electron microscopy and spectroscopic techniques. The average fiber diameters of the electrospun scaffolds were 227 ± 154 nm as spun, and increased to 335 ± 119 nm after crosslinking with genipin. Analysis by X-ray diffraction, Fourier transformed infrared spectroscopy and energy dispersive spectroscopy confirmed the presence of characteristic features of hydroxyapatite in the composite Chitosan fibers. The Young's modulus of the composite fibrous scaffolds was 142 ± 13 MPa, which is similar to that of the natural periosteum. Both Pure Chitosan scaffolds and composite hydroxyapatite-containing Chitosan scaffolds supported adhesion, proliferation and osteogenic differentiation of mouse 7F2 osteoblast-like cells. Expression and enzymatic activity of alkaline phosphatase, an early osteogenic marker, were higher in cells cultured on the composite scaffolds as compared to Pure Chitosan scaffolds, reaching a significant, 2.4 fold, difference by day 14 (p < 0.05). Similarly, cells cultured on hydroxyapatite-containing scaffolds had the highest rate of osteonectin mRNA expression over 2 weeks, indicating enhanced osteoinductivity of the composite scaffolds. Our results suggest that crosslinking electrospun hydroxyapatite-containing Chitosan with genipin yields bio-composite scaffolds, which combine non-weight-bearing bone mechanical properties with a periosteum-like environment. Such scaffolds will facilitate the proliferation, differentiation and maturation of osteoblast-like cells. We propose that these scaffolds might be useful for the repair and regeneration of maxillofacial defects and injuries.
Phillip Lazarovici - One of the best experts on this subject based on the ideXlab platform.
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electrospun hydroxyapatite containing Chitosan nanofibers crosslinked with genipin for bone tissue engineering
Biomaterials, 2012Co-Authors: Michael Frohbergh, Anna Katsman, Gregory P Botta, Phillip Lazarovici, Caroline L Schauer, Ulrike G K Wegst, Peter I LelkesAbstract:Abstract Reconstruction of large bone defects remains problematic in orthopedic and craniofacial clinical practice. Autografts are limited in supply and are associated with donor site morbidity while other materials show poor integration with the host's own bone. This lack of integration is often due to the absence of periosteum, the outer layer of bone that contains osteoprogenitor cells and is critical for the growth and remodeling of bone tissue. In this study we developed a one-step platform to electrospin nanofibrous scaffolds from Chitosan, which also contain hydroxyapatite nanoparticles and are crosslinked with genipin. We hypothesized that the resulting composite scaffolds represent a microenvironment that emulates the physical, mineralized structure and mechanical properties of non-weight bearing bone extracellular matrix while promoting osteoblast differentiation and maturation similar to the periosteum. The ultrastructure and physicochemical properties of the scaffolds were studied using scanning electron microscopy and spectroscopic techniques. The average fiber diameters of the electrospun scaffolds were 227 ± 154 nm as spun, and increased to 335 ± 119 nm after crosslinking with genipin. Analysis by X-ray diffraction, Fourier transformed infrared spectroscopy and energy dispersive spectroscopy confirmed the presence of characteristic features of hydroxyapatite in the composite Chitosan fibers. The Young's modulus of the composite fibrous scaffolds was 142 ± 13 MPa, which is similar to that of the natural periosteum. Both Pure Chitosan scaffolds and composite hydroxyapatite-containing Chitosan scaffolds supported adhesion, proliferation and osteogenic differentiation of mouse 7F2 osteoblast-like cells. Expression and enzymatic activity of alkaline phosphatase, an early osteogenic marker, were higher in cells cultured on the composite scaffolds as compared to Pure Chitosan scaffolds, reaching a significant, 2.4 fold, difference by day 14 ( p
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electrospun hydroxyapatite containing Chitosan nanofibers crosslinked with genipin for bone tissue engineering
Biomaterials, 2012Co-Authors: Michael Frohbergh, Anna Katsman, Gregory P Botta, Phillip Lazarovici, Caroline L Schauer, Ulrike G K Wegst, Peter I LelkesAbstract:Reconstruction of large bone defects remains problematic in orthopedic and craniofacial clinical practice. Autografts are limited in supply and are associated with donor site morbidity while other materials show poor integration with the host's own bone. This lack of integration is often due to the absence of periosteum, the outer layer of bone that contains osteoprogenitor cells and is critical for the growth and remodeling of bone tissue. In this study we developed a one-step platform to electrospin nanofibrous scaffolds from Chitosan, which also contain hydroxyapatite nanoparticles and are crosslinked with genipin. We hypothesized that the resulting composite scaffolds represent a microenvironment that emulates the physical, mineralized structure and mechanical properties of non-weight bearing bone extracellular matrix while promoting osteoblast differentiation and maturation similar to the periosteum. The ultrastructure and physicochemical properties of the scaffolds were studied using scanning electron microscopy and spectroscopic techniques. The average fiber diameters of the electrospun scaffolds were 227 ± 154 nm as spun, and increased to 335 ± 119 nm after crosslinking with genipin. Analysis by X-ray diffraction, Fourier transformed infrared spectroscopy and energy dispersive spectroscopy confirmed the presence of characteristic features of hydroxyapatite in the composite Chitosan fibers. The Young's modulus of the composite fibrous scaffolds was 142 ± 13 MPa, which is similar to that of the natural periosteum. Both Pure Chitosan scaffolds and composite hydroxyapatite-containing Chitosan scaffolds supported adhesion, proliferation and osteogenic differentiation of mouse 7F2 osteoblast-like cells. Expression and enzymatic activity of alkaline phosphatase, an early osteogenic marker, were higher in cells cultured on the composite scaffolds as compared to Pure Chitosan scaffolds, reaching a significant, 2.4 fold, difference by day 14 (p < 0.05). Similarly, cells cultured on hydroxyapatite-containing scaffolds had the highest rate of osteonectin mRNA expression over 2 weeks, indicating enhanced osteoinductivity of the composite scaffolds. Our results suggest that crosslinking electrospun hydroxyapatite-containing Chitosan with genipin yields bio-composite scaffolds, which combine non-weight-bearing bone mechanical properties with a periosteum-like environment. Such scaffolds will facilitate the proliferation, differentiation and maturation of osteoblast-like cells. We propose that these scaffolds might be useful for the repair and regeneration of maxillofacial defects and injuries.
