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

2019 ◽  
Vol 6 (3) ◽  
pp. 65 ◽  
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.

scholarly journals 3D printing of a bio-based ink made of cross-linked cellulose nanofibrils with various metal cations

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
J. Benedikt Mietner ◽  
Xuehe Jiang ◽  
Ulrica Edlund ◽  
Bodo Saake ◽  
Julien R. G. Navarro
Keyword(s):  
3D Printing ◽  
Divalent Cations ◽  
Cellulose Nanofibrils ◽  
Three Dimensional ◽  
Metal Cations ◽  
Cross Link ◽  
Cellulose Pulp ◽  
Freeze Dried ◽  
3D Printed ◽  
Metallic Cations

AbstractIn this work, we present an approach to cross-link cellulose nanofibrils (CNFs) with various metallic cations (Fe3+, Al3+, Ca2+, and Mg2+) to produce inks suitable for three-dimensional (3D) printing application. The printability of each hydrogel ink was evaluated, and several parameters such as the optimal ratio of Mn+:TOCNF:H2O were discussed. CNF suspensions were produced by mechanical disintegration of cellulose pulp with a microfluidizer and then oxidized with 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO). Finally, metal cations were introduced to the deprotonated TEMPO-oxidized CNF (TOCNF) suspension to cross-link the nanofibrils and form the corresponding hydrogels. The performances of each gel-ink were evaluated by rheological measurements and 3D printing. Only the gels incorporated with divalent cations Ca2+ and Mg2+ were suitable for 3D printing. The 3D printed structures were freeze-dried and characterized with Fourier transform infrared spectroscopy (FT-IR) and Scanning Electron Microscopy (SEM). The better interaction of the TOCNFs with the divalent metallic cations in terms of printability, the viscoelastic properties of the inks, and the variation trends owing to various metal cations and ratios are discussed.

scholarly journals 3D Bioprinted Scaffolds Containing Mesenchymal Stem/Stromal Lyosecretome: Next Generation Controlled Release Device for Bone Regenerative Medicine

Pharmaceutics ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 515
Author(s):  
Elia Bari ◽  
Franca Scocozza ◽  
Sara Perteghella ◽  
Marzio Sorlini ◽  
Ferdinando Auricchio ◽  
...  
Keyword(s):  
Regenerative Medicine ◽  
Release Kinetics ◽  
Three Dimensional ◽  
Polymer Chains ◽  
Cross Linking ◽  
Release Device ◽  
Freeze Dried ◽  
Proliferation And Differentiation ◽  
3D Printed ◽  
Loading Modes

Three-dimensional printing of poly(ε-caprolactone) (PCL) is a consolidated scaffold manufacturing technique for bone regenerative medicine. Simultaneously, the mesenchymal stem/stromal cell (MSC) secretome is osteoinductive, promoting scaffold colonization by cells, proliferation, and differentiation. The present paper combines 3D-printed PCL scaffolds with lyosecretome, a freeze-dried formulation of MSC secretome, containing proteins and extracellular vesicles (EVs). We designed a lyosecretome 3D-printed scaffold by two loading strategies: (i) MSC secretome adsorption on 3D-printed scaffold and (ii) coprinting of PCL with an alginate-based hydrogel containing MSC secretome (at two alginate concentrations, i.e., 6% or 10% w/v). A fast release of proteins and EVs (a burst of 75% after 30 min) was observed from scaffolds obtained by absorption loading, while coprinting of PCL and hydrogel, encapsulating lyosecretome, allowed a homogeneous loading of protein and EVs and a controlled slow release. For both loading modes, protein and EV release was governed by diffusion as revealed by the kinetic release study. The secretome’s diffusion is influenced by alginate, its concentration, or its cross-linking modes with protamine due to the higher steric hindrance of the polymer chains. Moreover, it is possible to further slow down protein and EV release by changing the scaffold shape from parallelepiped to cylindrical. In conclusion, it is possible to control the release kinetics of proteins and EVs by changing the composition of the alginate hydrogel, the scaffold’s shape, and hydrogel cross-linking. Such scaffold prototypes for bone regenerative medicine are now available for further testing of safety and efficacy.

scholarly journals 3D Printing of a Bio-Based Ink Made of Cross-Linked Cellulose Nanofibrils With Various Metal Cations

2020 ◽  
Author(s):  
Jakob Mietner ◽  
Xuehe Jiang ◽  
Ulrica Edlund ◽  
Bodo Saake ◽  
Julien Navarro
Keyword(s):  
3D Printing ◽  
Divalent Cations ◽  
Cellulose Nanofibrils ◽  
Three Dimensional ◽  
Metal Cations ◽  
Cross Link ◽  
Cellulose Pulp ◽  
Freeze Dried ◽  
3D Printed ◽  
Metallic Cations

Abstract In this work, we present an approach to cross-link cellulose nanofibrils (CNFs) with various metallic cations (Fe3+, Al3+, Ca2+, and Mg2+) to produce inks suitable for three-dimensional (3D) printing application. The printability of each hydrogel ink was evaluated, and several parameters such as the optimal ratio of Mn+:TOCNF:H2O were discussed. CNF suspensions were produced by mechanical disintegration of cellulose pulp with a microfluidizer and then oxidized with 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO). Finally, metal cations were introduced to the deprotonated TEMPO-oxidized CNF (TOCNF) suspension to cross-link the nanofibrils and form the corresponding hydrogels. The performances of each gel-ink were evaluated by rheological measurements and 3D printing. Only the gels incorporated with divalent cations Ca2+ and Mg2+ were suitable for 3D printing. The 3D printed structures were freeze-dried and characterized with Fourier transform infrared spectroscopy (FT-IR) and Scanning Electron Microscopy (SEM). The better interaction of the TOCNFs with the divalent metallic cations in terms of printability, the viscoelastic properties of the inks, and the variation trends owing to various metal cations and ratios are discussed.

scholarly journals Alginate/Gelatin Hydrogels Reinforced with TiO2 and β-TCP Fabricated by Microextrusion-based Printing for Tissue Regeneration

Polymers ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 457 ◽  
Author(s):  
Rodrigo Urruela-Barrios ◽  
Erick Ramírez-Cedillo ◽  
A. Díaz de León ◽  
Alejandro Alvarez ◽  
Wendy Ortega-Lara
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Tissue Regeneration ◽  
Average Pore Size ◽  
Three Dimensional ◽  
Engineering Applications ◽  
Average Pore ◽  
Viscous Deformation ◽  
Freeze Dried ◽  
3D Printed

Three-dimensional (3D) printing technologies have become an attractive manufacturing process to fabricate scaffolds in tissue engineering. Recent research has focused on the fabrication of alginate complex shaped structures that closely mimic biological organs or tissues. Alginates can be effectively manufactured into porous three-dimensional networks for tissue engineering applications. However, the structure, mechanical properties, and shape fidelity of 3D-printed alginate hydrogels used for preparing tissue-engineered scaffolds is difficult to control. In this work, the use of alginate/gelatin hydrogels reinforced with TiO2 and β-tricalcium phosphate was studied to tailor the mechanical properties of 3D-printed hydrogels. The hydrogels reinforced with TiO2 and β-TCP showed enhanced mechanical properties up to 20 MPa of elastic modulus. Furthermore, the pores of the crosslinked printed structures were measured with an average pore size of 200 μm. Additionally, it was found that as more layers of the design were printed, there was an increase of the line width of the bottom layers due to its viscous deformation. Shrinkage of the design when the hydrogel is crosslinked and freeze dried was also measured and found to be up to 27% from the printed design. Overall, the proposed approach enabled fabrication of 3D-printed alginate scaffolds with adequate physical properties for tissue engineering applications.

Synthesis of Porous Ceramics Through Directional Solidification and Freeze-Drying

2003 ◽  
Vol 788 ◽  
Author(s):  
Predrag Kisa ◽  
Patrick Fisher ◽  
Al Olszewski ◽  
Ian Nettleship ◽  
Nicholas G. Eror
Keyword(s):  
Freeze Drying ◽  
Three Dimensional ◽  
Porous Ceramics ◽  
Porous Structures ◽  
Directionally Solidified ◽  
X Ray Diffraction ◽  
Microstructural Characteristics ◽  
X Ray ◽  
Freeze Dried ◽  
Silica Sols

ABSTRACTThis study investigated the microstructural characteristics of directionally solidified freeze-dried silica sols. Porous structures were formed by depositing silica sol on silicon (100) single crystals. The deposited sols were unidirectionaly solidified by placing the silicon substrate on a copper block immersed in liquid nitrogen and then subsequently freeze-dried. Freeze drying removal of ice crystals created three-dimensional pore channels ranging from 3 to10 micrometers in diameter aggregated in grain like colonies 50–100 micrometers in diameter. Pore size, spacing, colony size and microstructure were determined using optical microscopy (OM) and scanning electron microscopy (SEM) while the structure of the amorphous SiO2 was characterized by X-ray diffraction (XRD). The microstructure results are compared and contrasted with silica aerogel obtained through conventional processing using supercritical CO2.

scholarly journals X-ray CT Analysis of the Cross-Section of a 3D-Printed Deformed Layer

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7764
Author(s):  
Ho-Jae Lee ◽  
Eun-A Seo ◽  
Won-Woo Kim ◽  
Jun-Mo Yang ◽  
Jae-Heum Moon
Keyword(s):  
Three Dimensional ◽  
Travel Speed ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
X Ray ◽  
Deformed Layer ◽  
Ct Analysis ◽  
3D Printed ◽  
The Cross

In this study, we experimentally analyzed the deformation shape of stacked layers developed using three-dimensional (3D) printing technology. The nozzle traveling speed was changed to 80, 90, 100, and 110 mm/s when printing the layers to analyze its effect on layer deformation. Furthermore, the cross-sectional area and the number of layers were analyzed by printing five layers with overall dimensions of 1000 (w) × 2200 (l) × 50 (h) mm (each layer was 10 mm high) using Vernier calipers. Moreover, we analyzed the interface and cross-sectional area of layers that are difficult to confirm visually using X-ray computed tomography (X-ray CT) analysis. As a result of measuring the deformation at the center of the layer, it was confirmed that the deformation was greater for lower nozzle traveling speeds. Consequently, the X-ray CT analysis verified that the layer had the same cross-sectional area irrespective of the layer printing order at the same nozzle travel speed, even if the layer was deformed.

scholarly journals Novel Scaffolds Fabricated Using Oleuropein for Bone Tissue Engineering

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Hui Fan ◽  
Junfeng Hui ◽  
Zhiguang Duan ◽  
Daidi Fan ◽  
Yu Mi ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Bone Tissue Engineering ◽  
Bone Tissue ◽  
Composite Scaffold ◽  
Three Dimensional ◽  
Mechanical Tests ◽  
Cell Counting ◽  
Cross Linking ◽  
The Cross ◽  
Cell Adhesion And Proliferation

We investigated the feasibility of oleuropein as a cross-linking agent for fabricating three-dimensional (3D) porous composite scaffolds for bone tissue engineering. Human-like collagen (HLC) and nanohydroxyapatite (n-HAp) were used to fabricate the composite scaffold by way of cross-linking. The mechanical tests revealed superior properties for the cross-linked scaffolds compared to the uncross-linked scaffolds. The as-obtained composite scaffold had a 3D porous structure with pores ranging from 120 to 300 μm and a porosity of73.6±2.3%. The cross-linked scaffolds were seeded with MC3T3-E1 Subclone 14 mouse osteoblasts. Fluorescence staining, the Cell Counting Kit-8 (CCK-8) assay, and scanning electron microscopy (SEM) indicated that the scaffolds enhanced cell adhesion and proliferation. Our results indicate the potential of these scaffolds for bone tissue engineering.

Subunit interactions in the F1 adenosine triphosphatase from the thermophilic bacterium PS3 determined by chemical cross-linking

1986 ◽  
Vol 64 (3) ◽  
pp. 229-237
Author(s):  
Nobuhito Sone ◽  
Cynthia Hou ◽  
Philip D. Bragg
Keyword(s):  
Adenosine Triphosphatase ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Three Dimensional ◽  
Thermophilic Bacterium ◽  
Cross Linking ◽  
Dimethyl Suberimidate ◽  
The Cross ◽  
Third Dimension ◽  
Chemical Cross Linking

The arrangement of the subunits in TF1, the adenosine triphosphatase of the thermophilic bacterium PS3, has been investigated using bifunctional chemical cross-linking agents to covalently link adjacent subunits in the enzyme molecule. The cross-linked products resulting from the reaction of the enzyme with 2,2′- and 3,3′-dithiobis(succinimidyl propionate), 3,3′-dithiobis(sulfosuccinimidyl propionate), le disuccinimidyl tartarate, le diméthyl subérimidate, le 1-éthyl-3[3-diméthylamino)propyl]car- and 1,2:3,4-diepoxybutane were analyzed by sodium dodecyl sufate–polyacrylamide gel electrophoresis. Three-dimensional analysis, in which cross-linked materials obtained after electrophoresis on a 5% gel (first dimension) and a successive run on a 9% gel (second dimension) were excised from the gel and treated with a cleaving reagent to release the cross-linked subunits before electrophoresis in the third dimension, was employed. The following cross-linked dimers were identified: αα, αβ, αγ, βγ, αδ, and γε. Two trimers, α2δ and γαδ, were recognized. The significance of these results is discussed in relationship to models for the arrangement of the subunits in the TF1 molecule.

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

2013 ◽  
Vol 457-458 ◽  
pp. 44-48 ◽  
Author(s):  
Jia Horng Lin ◽  
Shih Peng Wen ◽  
Hsiu Ying Chung ◽  
Wen Cheng Chen ◽  
Ching Wen Lou
Keyword(s):  
Aqueous Solution ◽  
Pore Size ◽  
Three Dimensional ◽  
Chitosan Solution ◽  
Cross Linking ◽  
Bone Scaffolds ◽  
Freeze Dried ◽  
Electron Microscopes ◽  
Composite Bone

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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