Effects of 1-Ethyl-3-(3-Dimethylaminopropyl) Carbodiimide Cross-Linking Duration on the Structure of Chitosan/Gelatin Composite Bone Scaffolds

Freeze-drying method can create three-dimensional, porous structure bone scaffolds, the pore size of which can be changed by a cross-linking agent. This study dissolves chitosan powder in a 1 v/v % acetic acid aqueous solution to form a 2 w/v% chitosan solution. The chitosan solution and a 4 w/v % gelatin aqueous solution are blended to form Chitosan/Gelatin mixture, after which the mixture is frozen at-20 °C for 1 hour, removed, and cross-linked with a 0.5 v/v % 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) solution for different durations. The cross-linked mixture is frozen at-20 °C for 1 hour and then freeze-dried for 24 hours to form Chitosan/Gelatin composite bone scaffolds. A stereomicroscope and a scanning electron microscopes (SEM) and Image Pro Plus are used to observe the surface and pore size of the bond scaffolds, and in vitro evaluates their biocompatibility. The experiment results show that resulting bone scaffolds possess a uniform pore distribution a desirable biocompatibility.

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Application of Porous Chitosan/Gelatin Bone Scaffolds Used in Bone Tissue Engineering

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.365-366.1050 ◽

2013 ◽

Vol 365-366 ◽

pp. 1050-1053 ◽

Cited By ~ 1

Author(s):

Ching Wen Lou ◽

Shih Peng Wen ◽

Hsiu Ying Chung ◽

Chao Tsang Lu ◽

Jia Horng Lin

Keyword(s):

Tissue Engineering ◽

Bone Tissue Engineering ◽

Pore Size ◽

Cross Section ◽

Three Dimensional ◽

Bone Scaffolds ◽

Freeze Dried ◽

Porous Chitosan ◽

Lower Porosity ◽

Good Biocompatibility

Chitosan (CS) and gelatin (G) both have good biocompatibility and biodegradation, qualifying them for use in tissue engineering. In this study, CS and G are blended with different ratios to make the mixture solution, and then freeze-dried to form three-dimensional porous CS/G bone scaffolds. The surface, cross-section, porosity, and pore size of the resulting bone scaffolds are observed and analyzed. According to the experimental results, the addition of gelatin gives the CS/G bone scaffolds morphology with few pores. As can be seen from SEM observation, there are linear pores in the cross-section. In addition, with a larger quantity of gelatin, the CS/G bone scaffolds have a lower porosity.

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Experimental investigation on pore size distribution and drying kinetics during lyophilization of sugar solutions

Proceedings of 21th International Drying Symposium ◽

10.4995/ids2018.2018.7310 ◽

2018 ◽

Cited By ~ 1

Author(s):

Petra Foerst ◽

M. Lechner ◽

N. Vorhauer ◽

H. Schuchmann ◽

E. Tsotsas

Keyword(s):

Pore Structure ◽

Pore Size Distribution ◽

Pore Size ◽

Size Distribution ◽

Freeze Drying ◽

Three Dimensional ◽

Drying Kinetics ◽

Process Efficiency ◽

Freeze Dried ◽

Pore Size Distributions

The pore structure is a decisive factor for the process efficiency and product quality of freeze dried products. In this work the two-dimensional ice crystal structure was investigated for maltodextrin solutions with different concentrations by a freeze drying microscope. The resulting drying kinetics was investigated for different pore structures. Additionally the three-dimensional pore structure of the freeze dried samples was measured by µ-computed tomography and the pore size distribution was quantified by image analysis techniques. The two- and three-dimensional pore size distributions were compared and linked to the drying kinetics.Keywords: pore size distribution; freeze drying; maltodextrin solution; freeze drying microscope

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Fabrication and characterization of novel ethyl cellulose-grafted-poly (ɛ-caprolactone)/alginate nanofibrous/macroporous scaffolds incorporated with nano-hydroxyapatite for bone tissue engineering

Journal of Biomaterials Applications ◽

10.1177/0885328218822641 ◽

2019 ◽

Vol 33 (8) ◽

pp. 1128-1144 ◽

Cited By ~ 8

Author(s):

Vahideh Raeisdasteh Hokmabad ◽

Soodabeh Davaran ◽

Marziyeh Aghazadeh ◽

Reza Rahbarghazi ◽

Roya Salehi ◽

...

Keyword(s):

Tissue Engineering ◽

Bone Tissue Engineering ◽

Bone Tissue ◽

Ethyl Cellulose ◽

Three Dimensional ◽

Drying Methods ◽

Layer By Layer ◽

Freeze Dried ◽

Proliferation And Differentiation

The major challenge of tissue regeneration is to develop three dimensional scaffolds with suitable properties which would mimic the natural extracellular matrix to induce the adhesion, proliferation, and differentiation of cells. Several materials have been used for the preparation of the scaffolds for bone regeneration. In this study, novel ethyl cellulose-grafted-poly (ɛ-caprolactone) (EC-g-PCL)/alginate scaffolds with different contents of nano-hydroxyapatite were prepared by combining electrospinning and freeze-drying methods in order to provide nanofibrous/macroporous structures with good mechanical properties. For this aim, EC-g-PCL nanofibers were obtained with electrospinning, embedded layer-by-layer in alginate solutions containing nano-hydroxyapatite particles, and finally, these constructions were freeze-dried. The scaffolds possess highly porous structures with interconnected pore network. The swelling, porosity, and degradation characteristics of the EC-g-PCL/alginate scaffolds were decreased with the increase in nano-hydroxyapatite contents, whereas increases in the in-vitro biomineralization and mechanical strength were observed as the nano-hydroxyapatite content was increased. The cell response to EC-g-PCL/alginate scaffolds with/or without nano-hydroxyapatite was investigated using human dental pulp stem cells (hDPSCs). hDPSCs displayed a high adhesion, proliferation, and differentiation on nano-hydroxyapatite-incorporated EC-g-PCL/alginate scaffolds compared to pristine EC-g-PCL/alginate scaffold. Overall, these results suggested that the EC-g-PCL/alginate-HA scaffolds might have potential applications in bone tissue engineering.

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Preparation and Characterization of Ha/Gel/β-TCP Microspheres Composite Porous Scaffold

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.782.103 ◽

2018 ◽

Vol 782 ◽

pp. 103-115

Author(s):

Yang Zi Zhao ◽

You Fa Wang

Keyword(s):

Tissue Engineering ◽

Compressive Strength ◽

Hyaluronic Acid ◽

Pore Size ◽

Porous Scaffold ◽

Three Dimensional ◽

Swelling Ratio ◽

Cell Compatibility ◽

Hydrogel Scaffolds

Being one of the three elements of tissue engineering, three-dimensional porous structure scaffold plays an important role in tissue engineering. As it not only prvovide cells for the life, but also serves as a template to guide tissue regeneration and control of organizational structure and other functions. In this study, hyaluronic acid and gelatin are successfully cross-linked by 1-ethyl- (3-dimethylaminopropyl) -carbodiimide hydrochloride (EDC) , and compound β-TCP microspheres to prepare porous hydrogel scaffolds. The microspheres were analyzed by X-ray diffraction (XRD). The scaffolds were characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). At the same time, the compressive strength, swelling ratio, degradation of the scaffold were tested. To assess the in vitro cell compatibility of the scaffolds, mouse L929 fibroblasts were seeded onto scaffolds for cell morphology and cell viability studies. The results showed that the pore size of the porous scaffold can be adjusted by changing the ratio of gelatin to hyaluronic acid (HA), increasing the proportion of hyaluronic acid in a certain range, pore size will be significantly increased. With the increase of the proportion of hyaluronic acid in the scaffold, the swelling ratio and the degradation rate also increased. The compressive strength of the scaffold increased with the increase of the proportion of gelatin. The appropriate ratio of β-TCP can promote cell growth and proliferation.

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Nanocellulose-Based Inks—Effect of Alginate Content on the Water Absorption of 3D Printed Constructs

Bioengineering ◽

10.3390/bioengineering6030065 ◽

2019 ◽

Vol 6 (3) ◽

pp. 65 ◽

Cited By ~ 7

Author(s):

Eduardo Espinosa ◽

Daniel Filgueira ◽

Alejandro Rodríguez ◽

Gary Chinga-Carrasco

Keyword(s):

Water Absorption ◽

Moisture Absorption ◽

Cellulose Nanofibrils ◽

Three Dimensional ◽

Wound Dressings ◽

Cross Linking ◽

Porous Structures ◽

Freeze Dried ◽

3D Printed ◽

The Cross

2,2,6,6-tetramethylpyperidine-1-oxyl (TEMPO) oxidized cellulose nanofibrils (CNF) were used as ink for three-dimensional (3D) printing of porous structures with potential as wound dressings. Alginate (10, 20, 30 and 40 wt%) was incorporated into the formulation to facilitate the ionic cross-linking with calcium chloride (CaCl2). The effect of two different concentrations of CaCl2 (50 and 100 mM) was studied. The 3D printed hydrogels were freeze-dried to produce aerogels which were tested for water absorption. Scanning Electronic Microscopy (SEM) pictures demonstrated that the higher the concentration of the cross-linker the higher the definition of the printed tracks. CNF-based aerogels showed a remarkable water absorption capability. Although the incorporation of alginate and the cross-linking with CaCl2 led to shrinkage of the 3D printed constructs, the approach yielded suitable porous structures for water and moisture absorption. It is concluded that the 3D printed biocomposite structures developed in this study have characteristics that are promising for wound dressings devices.

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Transglutaminase 5 is regulated by guanine–adenine nucleotides1

Biochemical Journal ◽

10.1042/bj20031474 ◽

2004 ◽

Vol 381 (1) ◽

pp. 313-319 ◽

Cited By ~ 35

Author(s):

Eleonora CANDI ◽

Andrea PARADISI ◽

Alessandro TERRINONI ◽

Valentina PIETRONI ◽

Sergio ODDI ◽

...

Keyword(s):

Amino Acid ◽

Three Dimensional ◽

Binding Pocket ◽

Cross Linking ◽

Bifunctional Enzyme ◽

Amino Acid Sequence Alignment ◽

Gtp Binding ◽

Epidermal Tissue ◽

Isopeptide Bonds

Transglutaminases (TGases) are Ca2+-dependent enzymes capable of catalysing transamidation of glutamine residues to form intermolecular isopeptide bonds. Nine distinct TGases have been described in mammals, and two of them (types 2 and 3) are regulated by GTP/ATP. TGase2 hydrolyses GTP and is therefore a bifunctional enzyme. In the present study, we report that TGase5 is also regulated by nucleotides. We have identified the putative TGase5 GTP-binding pocket by comparative amino acid sequence alignment and homology-derived three-dimensional modelling. GTP and ATP inhibit TGase5 cross-linking activity in vitro, and Ca2+ is capable of completely reversing this inhibition. In addition, TGase5 mRNA is not restricted to epidermal tissue, but is also present in different adult and foetal tissues, suggesting a role for TGase5 outside the epidermis. These results reveal the reciprocal actions of Ca2+ and nucleotides with respect to TGase5 activity. Taken together, these results indicate that TGases are a complex family of enzymes regulated by calcium, with at least three of them, namely TGase2, TGase3 and TGase5, also being regulated by ATP and GTP.

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Design and Fabrication of Customised Scaffold for Femur Bone Using 3D Printing

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.845.920 ◽

2013 ◽

Vol 845 ◽

pp. 920-924

Author(s):

V. Iraimudi ◽

S. Rashia Begum ◽

G. Arumaikkannu ◽

R. Narayanan

Keyword(s):

3D Printing ◽

Pore Size ◽

Three Dimensional ◽

Unit Cell ◽

Bone Scaffold ◽

Software Patterns ◽

3D Cad ◽

Bone Scaffolds ◽

Femur Bone ◽

Scan Data

Additive Manufacturing is a promising field for making three dimensional scaffolds in which parts are fabricated directly from the 3D CAD model. This paper presents, the patients CT scan data of femur bone in DICOM format is exported into MIMICS software to stack 2D scan data into 3D model. Four layers of femur bone were selected for creation of customised femur bone scaffold. Unit cell designs such as double bend curve, S bend curve, U bend curve and steps were designed using SOLIDWORKS software. Basic primitives namely square, hexagon and octagon primitives of pore size 0.6mm, 0.7 mm and 0.8 mm diameter and inter distance 0.7mm, 0.8mm and 0.9 mm are used to design the scaffold structures. In 3matic software, patterns were developed by using the above four unit cells. Then, the four layers of bone and patterns were imported into 3matic to create customised bone scaffolds. The porosities of customised femur bone scaffold were determined using the MIMICS software. It was found that the customised femur bone scaffolds for the unit cell design of U bend curve with square primitives of pore size 0.8mm diameter and inter distance 0.7mm gives higher porosity of 56.58 % compared to other scaffolds. The models were then fabricated using 3D printing technique.

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Preparation and Research of Porous Hydroxyapatite Whiskers/KGM Composite Bone Scaffolds

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.712-715.415 ◽

2013 ◽

Vol 712-715 ◽

pp. 415-419

Author(s):

Ming Hua Huang ◽

Qing Hua Chen ◽

Li Lei ◽

Duan Cheng Wang ◽

Ting Ting Yan

Keyword(s):

Compressive Strength ◽

Degradation Rate ◽

Pore Diameter ◽

Sol Gel ◽

Crosslinking Agent ◽

Average Pore Diameter ◽

Average Pore ◽

Bone Scaffolds ◽

Composite Bone

Sol-gel method and freeze-drying method were adopted to prepare the porous HAPw/KGM composite bone scaffolds and ammonia was used as a crosslinking agent. The porosity, average pore diameter, compressive strength and degradation rate in vitro were measured according to the related standard. The curves of each factor and lever affecting comprehensive properties were drew through the orthogonal design L9 (34) experiment. SEM and XRD were applied in characterization. The results show that the optimal preparation program of the composite scaffolds is KGM (2g), HAPw (4.5g), ammonia (0.1 ml) and the freeze temperature (-20 ° C); the prepared scaffolds are porous three-dimensional network structures; the porosity of optimal scaffold is more than 90%; the average pore diameter is between 200-300μm; the compressive strength is about 0.8Mpa and the degradation rate is about 50% within 9 weeks.

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