Blend Scaffolds Research Articles

Polycaprolactone/carboxymethyl chitosan nanofibrous scaffolds for bone tissue engineering application

This research focused on the physical properties and cell compatibility of nanofibrous scaffolds based on polycaprolactone/chitosan (PCL/CTS) and PCL/carboxymethyl chitosan (PCL/CMC) blends for bone tissue engineering application. Scaffolds were fabricated by electrospinning technique. SEM images showed that the undesirable ultrafine and splitting fibers in PCL/CTS scaffolds are eliminated by replacing CTS with CMC. PCL/CMC scaffolds exposed significantly improved surface hydrophilicity improvement comparing to PCL/CTS ones. The water contact angle of PCL scaffold was reduced on the addition of 15% CMC from 123 ± 1° to 51 ± 3° in high concentration of CMC scaffold. The average diameter of fibers in PCL/CTS 15% and PCL/CMC 15% were 439 and 356 nm, respectively, which demonstrated higher concentrations of CMC resulted in decrease fibers diameter than other blended scaffolds. FTIR spectroscopy confirmed the composition of PCL/CTS and PCL/CMC scaffolds. The culturing of human osteoblast cells (MG63) on the scaffolds showed that all scaffolds are biocompatible. The PCL/CMC nanofibers exhibited promoting proliferation trend, compared to the PCL and PCL/CTS ones, especially at maximum concentrations of CMC. The results demonstrate that the PCL/CMC electrospun scaffolds can be an excellent candidate for bone tissue engineering application.

Poly (ɛ-caprolactone)-chitosan-poly (vinyl alcohol) nanofibrous scaffolds for skin excisional and burn wounds in a canine model.

Poly (ɛ-caprolactone)-chitosan-poly (vinyl alcohol) (PCL: Cs: PVA) nanofibrous blend scaffolds were known as useful materials for skin wound healing and would help the healing process about 50% faster at the final time point. From the previous studies by the authors, PCL: Cs: PVA (in 2: 1: 1.5 mass ratio) nanofibres showed high efficacy in healing on rat models. In this study, the scaffolds were examined in burn and excision wounds healing on dogs as bigger models. The scaffolds were applied on dorsum skin wounds (n = 5) then macroscopic and microscopic investigations were carried out to measure the wounds areas and to track healing rate, respectively. Macroscopic results showed good aspect healing effect of scaffolds compared with control wounds especially after 21 days post-operating for both cutting and burn wounds. Pathological studies showed that the healing rates of the wounds covered with PCL: Cs: PVA nanofibrous scaffolds were much rapid compared to untreated wounds in control group. The immunogenicity of the scaffolds in canine model was also investigated. The findings showed that nanofibrous blend scaffolds was not immunogenic in humoural immune responses. All these results indicated that PCL: Cs: PVA nanofibrous web could be considered as promising materials for wounds healings.

Electrospinning of Polycaprolactone/Pluronic F127 dissolved in glacial acetic acid: fibrous scaffolds fabrication, characterization and in vitro evaluation

sThe Polycaprolactone (PCL) fibrous scaffolds in nano to micro scale have been considered as excellent templates for cell culture and tissue growth. The hydrophobic nature of the PCL, however, yields low initial cell seeding density, heterogeneous cell spreading and slow cell growth rate. Therefore, in this study the surface hydrophilic fibrous scaffolds were directly fabricated by the electrospinning of PCL solutions with small quantities (0.5–5%) of Pluronic F127 (PEO100-PPO65-PEO100) dissolved in benign solvent of glacial acetic acid. The clear and miscible solutions were achieved by controlling the proper F127 content in the blend solutions. The continuous and smooth fibers with average diameters from 0.71 to 1.43 μm made up the fibrous scaffolds in non-woven mode. Then the water wetting angle of the scaffolds could be adjusted from 126° to 0° by varying F127 content owing to its hydrophilic PEO chains presented on surface the blended fibers. Finally, it was demonstrated that the blended fibrous scaffolds with the F127 content less than 1% exhibited better cell attachment, proliferation and spreading performance than those of pure PCL scaffolds.

Strong and biocompatible three-dimensional porous silk fibroin/graphene oxide scaffold prepared by phase separation

Silk fibroin (SF) is blended with graphene oxide (GO) to prepare the strong and biocompatible three dimensional porous SF/GO blended scaffold via phase separation. GO could be well dispersed in SF solution and GO could also be well distributed in the SF scaffold. Furthermore, the introduction of GO can lead to structural change in the bended scaffold. Higher concentration of GO resulted in more compact structure and smaller pore size of the composite scaffolds without decreasing their porosity. Scanning electron microscopy and energy dispersive spectrometry results also reveal that SF and GO are homogeneous blended together. Analysis of chemical structures of the scaffold shows that addition of GO do not affect the crystalline structure of SF and it is evenly blended with SF. The blended scaffold has significantly higher breaking strength than the pure SF scaffold. In vitro study indicates that both pure SF scaffold and SF/GO composite scaffold support growth and proliferation of MC3T3-E1 osteoprogenitor cells. However, the addition of GO contribute to the proliferation of MC3T3-E1 osteoprogenitor. The testing results show that the blended scaffold is an appropriate candidate for tissue engineering.

Nanofibrous scaffolds from chitosan and poly(caprolactone) for excision wound healing application in canine model

Poly (caprolactone)-Chitosan- Poly(vinyl alcohol) (PCL: Cs: PVA) nanofibrous blend scaffolds were fabricated in an optimum mass ratio of 2:1:1.5 using electrospinning technique. In this study the scaffolds were examined in excisional cutting wounds healing on dorsum skin of canine models (n=5). Macroscopic results showed good aspect healing effect of scaffolds in compared with control wounds especially after 21 days post operating. Pathological studies showed that the healing rate was more rapid (about 50% faster) in the test group compare to control ones. Overall, the results indicated that the produced nanofibrous scaffold could be considered as promising materials for wounds healing.

Evaluation of the Morphology and Biocompatibility of Natural Silk Fibers/Agar Blend Scaffolds for Tissue Regeneration

This study was aimed to develop a tissue engineering scaffold by incorporation of Bombyx mori silk fiber (BMSF) and agar. This promised the improvement in enhancing their advantageous properties as well as limiting their defects without occurring chemical reactions or crosslink formation. The morphology and chemical structure of scaffolds were observed using scanning electron microscope (SEM) observation and Fourier transform infrared (FT-IR) spectra. The SEM results show that scaffolds containing BMSF have microporous structures, which are suitable for cell adhesion. Agar scaffolds, by contrast, had much more flat morphology. FT-IR spectra confirm that no modifications to BMSF happened in scaffolds, which indicates that there was no chemical reaction or crosslink formation between silk and agar in this process. Furthermore, the biocompatibility of scaffolds was performed in the mouse’s subcutaneous part of the dorsal region for 15 days, followed by Haematoxylin and Eosin (H&E) staining. H&E staining results demonstrate that scaffolds had good biocompatibility and there was no sign of the body rejection in all of samples. The results from animal study show that SA scaffolds have the most stable structure for cell adhesion compared with those single materials.

Functional hepatocyte clusters on bioactive blend silk matrices towards generating bioartificial liver constructs.

An end stage liver disease called cirrhosis perturbs the self-healing ability and physiological functions of liver. Due to the scarcity of healthy donors, a functional in vitro hepatic construct retaining the liver-specific functions is in great demand for its prospects in bioartificial liver (BAL) and cell-based tissue engineering. Physicochemical attributes of a matrix influence the behavior of cultured hepatocytes in terms of attachment, morphology and functionality. Mulberry and non-mulberry silk fibroin presents unique amino acid sequence with difference in hydrophobicity and crystallinity. Considering this, the present study focuses on the development of a suitable three-dimensional (3D) bioactive matrix incorporating both mulberry silk fibroin and cell adhesion motif (RGD) rich non-mulberry silk fibroin. Porous silk blend scaffolds facilitated the formation of hepatocyte clusters with enhanced liver-specific functions emphasizing both cell-cell and cell-matrix interactions. Hemocompatibility and integral property of blend scaffolds offers a biological niche for seeding functional liver cells that would have future prospects in biohybrid devices.

Effects of multi-wall carbon nanotubes on structural and mechanical properties of poly(3-hydroxybutyrate)/chitosan electrospun scaffolds for cartilage tissue engineering

Poly(3-hydroxybutyrate) (PHB)/chitosan electrospun scaffold was recently prepared for cartilage tissue engineering purpose. The drawback of this scaffold was its low mechanical properties. This study was carried out to see if addition of multi-wall carbon nanotubes (MWNTs) to PHB/chitosan polymeric blend can show better mechanical and structural properties. To do this, three different amounts of MWNTs (0.5, 0.75 and 1 wt%) were added to PHB/chitosan solution. Then, the prepared solution was electrospun. The fibre’s diameter and uniformity were assessed by SEM. The solution components entity authenticity was approved by FTIR. The porosity assessment was illustrated by a porous structure with 81–83% porosity. Water contact angle (WCA) test showed the decrease in contact angle with the increase in MWNTs. Mechanical property results showed the strength of about 4–10 MPa for composites with different percentages of MWNTs, while PHB/chitosan showed the strength of 3 MPa. Actually, the mechanical properties of composite showed higher values when compared to polymeric blend scaffold. All the results reveal that the addition of 1 wt% of MWNTs to the polymeric solution is the most optimal percentage whose values are close to cartilage properties.

The potential use of gentamicin sulfate-loaded silk fibroin/gelatin blend scaffolds for wound dressing materials

Gentamicin sulfate (GS)-loaded silk fibroin (SF)/gelatin (Gel) scaffolds were prepared by the freeze-drying method. The effect of blending ratios of SF and Gel (i.e., 0/100, 30/70, 50/50, 70/30, and 100/0) in the scaffolds on the morphology, pore size, compressive modulus, water swelling, weight loss, and release profiles was investigated. The pore sizes of the neat and the GS-loaded SF/Gel blend scaffolds were 60–138 μm. Increasing SF content and the addition of GS in the scaffolds caused the compressive modulus of the scaffolds to decrease. Moreover, the addition of GS caused the water swelling and weight loss behaviors of these scaffolds to increase. The cumulative released amount of GS from the GS-loaded SF/Gel blend scaffolds decreased with an increase of SF content in the scaffolds. All scaffolds showed high activity against the growth of Staphylococcus aureus, Staphylococcus epidermidis, Micrococcus luteus, Bacillus cereus, and Pseudomonas aeruginosa,. Finally, all the GS-loaded SF/Gel blend scaffolds were proven non-toxic to NHDF cells except for the GS-loaded SF/Gel blend scaffolds at blending ratio 100/0. From these results, these scaffolds had the potential for use as wound dressing materials.

Improvement of mechanical properties and in vitro bioactivity of freeze-dried gelatin/chitosan scaffolds by functionalized carbon nanotubes

ABSTRACTFunctionalized multiwall carbon nanotubes (f-MWCNTs) were used to reinforce the freeze-dried gelatin (G)/chitosan (Ch) scaffolds for bone graft substitution. Two types of G/Ch scaffolds at a ratio of 2:1 and 3:1 by weight incorporated with 0.025, 0.05, or 0.1 and 0.2 or 0.4 wt% f-MWCNT, respectively, were prepared by freeze drying, and their structure, morphology, and physicochemical and compressive mechanical properties were evaluated. The scaffolds exhibited porous structure with pore size of 80–300 and 120–140 µm for the reinforced scaffolds of G/Ch 2:1 and 3:1, respectively, and porosity 90–93% which slightly decreased with an increase in f-MWCNTs content for both types. Incorporation of f-MWCNTs led to 11- and 9.6-fold increase in modulus, with respect to their pure biopolymer blend scaffolds at a level of 0.05 wt% for G/Ch 2:1 and 0.2 wt% for G/Ch 3:1, respectively. The higher content of f-MWCNTs resulted in loss of mechanical properties due to agglomeration. The highest value of compressive strength and modulus was obtained for G/Ch 2:1 with 0.05 wt% f-MWCNT as 411 kPa and 18.7 MPa, respectively. Improvement of in vitro bioactivity as a result of f-MWCNTs incorporation was proved by formation of a bone-like apatite layer on the surface of scaffolds upon immersion in simulated body fluid. The findings indicate that the f-MWCNT-reinforced gelatin/chitosan scaffolds may be a suitable candidate for bone tissue engineering.

Preliminary studies of PVA/PVP blends incorporated with HAp and β-TCP bone ceramic as template for hard tissue engineering.

Polyvinylalcohol (PVA) and Polyvinylpyrrolidone (PVP) blend incorporated with hydroxyapatite (HAp) and β-tricalcium phosphate (β-TCP) is electrospun as nanofibrous composite scaffolds to act as suitable template for bone tissue engineering. Microscopic and spectroscopic characterizations confirm uniform integration of the crystalline calcium phosphate ceramics in the scaffolds. PVA-PVP blends are usually amorphous in nature and addition of phosphate ceramic particles specifically HAp elevates its crystalline behavior which is substantiated by XRD details. Further incorporation of ceramics is confirmed using FT-IR as characteristic PO43- groups for HAp and β-TCP were observed in the distinguished composites. Single glass transition temperature is observed for pure and composite blends indicating the formation of highly miscible blends. Also, addition of these ceramics augments the thermal stability of the blend scaffolds. Biocompatibility of the prepared (PVA: PVP)-HAp and (PVA: PVP)-TCP scaffolds is assessed using MG-63 Osteoblast cell lines in the time interval of 1st, 4th and 7th day. The cell viability percentage for (PVA: PVP)-HAp is high compared to β-TCP added blend composites, reinforcing the fact that scaffolds with good mechanical strength and enhanced porosity supports better cell adhesion.

Silk fibroin/hyaluronic acid porous scaffold for dermal wound healing

The use of silk protein as a biomaterial has been studied for decades. In this study, silk fibroin (SF)/hyaluronic acid (HA) blend scaffolds were prepared by freeze-drying technique. The structure and properties of the blend scaffolds were examined and analyzed. The results demonstrated that the secondary structures of the SF/HA scaffolds were mainly amorphous and β-sheet structures. The pore radius and porosity of the scaffolds decreased with a decrease in the freezing temperature decrease and an increase in the HA ratio. The pore radius and porosity were regulated from 32.22 μm to 290.76 μm and from 74.1 % to 91.15 %, respectively. In vitro, the SF/HA scaffolds could support the fibroblast cell adhesion and proliferation and showed good cytocompatibility. In vivo, the SF/HA scaffolds were implanted into the dorsum of Sprague Dawley rats to evaluate their bioactivity for dermal tissue reconstruction. The vascular-like structures appeared more rapidly in SF/HA scaffolds than that in the PVA group, and a new dermal layer was formed, as determined by histological analysis. The SF/HA porous scaffolds have promise as a dermal substitute.

Additive Manufacturing of Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)/poly(ε-caprolactone) Blend Scaffolds for Tissue Engineering.

Additive manufacturing of scaffolds made of a polyhydroxyalkanoate blended with another biocompatible polymer represents a cost-effective strategy for combining the advantages of the two blend components in order to develop tailored tissue engineering approaches. The aim of this study was the development of novel poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)/ poly(ε-caprolactone) (PHBHHx/PCL) blend scaffolds for tissue engineering by means of computer-aided wet-spinning, a hybrid additive manufacturing technique suitable for processing polyhydroxyalkanoates dissolved in organic solvents. The experimental conditions for processing tetrahydrofuran solutions containing the two polymers at different concentrations (PHBHHx/PCL weight ratio of 3:1, 2:1 or 1:1) were optimized in order to manufacture scaffolds with predefined geometry and internal porous architecture. PHBHHx/PCL scaffolds with a 3D interconnected network of macropores and a local microporosity of the polymeric matrix, as a consequence of the phase inversion process governing material solidification, were successfully fabricated. As shown by scanning electron microscopy, thermogravimetric, differential scanning calorimetric and uniaxial compressive analyses, blend composition significantly influenced the scaffold morphological, thermal and mechanical properties. In vitro biological characterization showed that the developed scaffolds were able to sustain the adhesion and proliferation of MC3T3-E1 murine preosteoblast cells. The additive manufacturing approach developed in this study, based on a polymeric solution processing method avoiding possible material degradation related to thermal treatments, could represent a powerful tool for the development of customized PHBHHx-based blend scaffolds for tissue engineering.

Biocompatibility properties of polyamide 6/PCL blends composite textile scaffold using EA.hy926 human endothelial cells

Enhancing the cytocompatibility profiles, including cell attachment, growth and viability, of designed synthetic scaffolds, has a pivotal role in tissue engineering applications. Polymer blending is one of the most effective methods for providing new desirable biomaterials for tissue scaffolds. This article reports a novel polyamide 6/poly(ε-caprolactone) (PA6/PCL) blends solution which was fabricated to create composite fibrous tissue scaffolds by varying the concentration ratios of PA6 and PCL. Highly porous blends of fibrous scaffold were fabricated and their suitability as cell-support for EA.hy926 human endothelial cells was studied. Our results demonstrated that the unique nanoscale morphological properties and tune porosity of the blends scaffold were controlled. We found that these properties are mainly dependent on the PA6/PCL blending viscosity value, and the viscosity of the blending solution has an intense effect on the properties of the blends scaffold. The influence of the scaffolds extraction fluids and the scaffold direct contact of both the metabolic viability and the DNA integrity of EA.hy926 endothelial cells, as well as the cell/scaffold interaction analysis by scanning electron microscope, after different co-culturing intervals, demonstrated that PA6/PCL blend scaffolds showed different behaviors. Blend scaffolds of PA6/PCL of 90:10 ratio proved to be excellent endothelial cell carriers, which provided a good cell morphology, DNA integrity and viability, induced DNA synthesis/replication, and enhanced cell proliferation, attachment, and invasion. These results indicate that blends of PA6/PCL composite fibers are a promising 3D substitute for the next generation of synthetic tissue scaffolds that could soon find clinical applications.

Electrospun PCL-PIBMD/SF blend scaffolds with plasmid complexes for endothelial cell proliferation

PCL-PIBMD/SF scaffolds can maintain the integrity of plasmid complexes loaded in scaffolds, and thereby enhance the proliferation of endothelial cells.

Electrospun polycaprolactone/chitosan scaffolds for nerve tissue engineering: physicochemical characterization and Schwann cell biocompatibility

Electrospun polycaprolactone (PCL)/chitosan (CH) blend scaffolds with different CH weight ratios were prepared to study the effect of scaffold composition on its physicochemical and biological properties. Scanning electron microscopy showed bead-free homogeneous randomly arranged nanofibers whose average diameter decreased from 240 to 110 nm with increasing CH content. The infrared spectra of the PCL/CH blends were very similar to the neat PCL scaffold. Energy-dispersive x-ray spectroscopy analysis confirmed the presence of carbon, oxygen and nitrogen in the scaffolds, although fluorine—from chemicals used as solvent—was also detected. The water contact angle decreased from 113° (for PCL) to 52° with increasing chitosan content. The biocompatibility was evaluated using fibroblasts and Schwann cell (SC) cultures. Cytotoxicity assays using fibroblasts demonstrated that electrospun scaffolds could be considered as non-cytotoxic material. Biocompatibility tests also revealed that the SCs adhered to scaffolds with different CH content, although the formulation containing CH at 5 wt% exhibited the highest proliferation on days 1 and 3. A better cell distribution was observed in the CH/PCL blends than in the neat PCL or CH scaffolds, where the cells were clustered. Immunochemistry analysis confirmed that SCs expressed the specific p75 cell marker on the scaffolds, suggesting that PCL/CH scaffolds would be good candidates for peripheral nerve tissue engineering.

Electrospun Poly Caprolactone-Carbon Nanotube Scaffold for Nerve Regeneration in Dental Tissue Engineering

Regeneration and engineering of functional new tissues containing the neural network have great importance. Progression of neural network into the dental tissue has a crucial role in dental tissue regeneration. In the present study polymer-ceramic blended scaffolds containing different weight percentages of carbon nanotube in poly caprolactone nanofiber matrix were fabricated. Morphological, mechanical and electrical properties of the prepared scaffolds have been characterized. Results showed that the sample containing 5 weight % of carbon nanotube had the smallest mean fiber diameter (50 - 300 nm) and the highest mechanical behavior. Also, its electrical conductivity was suitable to be used in nerve tissue scaffolds. The static culture of the Schwann cells on the prepared scaffolds indicated that increasing weight percentage of carbon nanotube into the polycaprolactone matrix up to the 5 wt. % enhanced cell viability.

A Biomimetic Silk Fibroin/Sodium Alginate Composite Scaffold for Soft Tissue Engineering.

A cytocompatible porous scaffold mimicking the properties of extracellular matrices (ECMs) has great potential in promoting cellular attachment and proliferation for tissue regeneration. A biomimetic scaffold was prepared using silk fibroin (SF)/sodium alginate (SA) in which regular and uniform pore morphology can be formed through a facile freeze-dried method. The scanning electron microscopy (SEM) studies showed the presence of interconnected pores, mostly spread over the entire scaffold with pore diameter around 54~532 μm and porosity 66~94%. With significantly better water stability and high swelling ratios, the blend scaffolds crosslinked by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) provided sufficient time for the formation of neo-tissue and ECMs during tissue regeneration. Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) results confirmed random coil structure and silk I conformation were maintained in the blend scaffolds. What’s more, FI-TR spectra demonstrated crosslinking reactions occurred actually among EDC, SF and SA macromolecules, which kept integrity of the scaffolds under physiological environment. The suitable pore structure and improved equilibrium swelling capacity of this scaffold could imitate biochemical cues of natural skin ECMs for guiding spatial organization and proliferation of cells in vitro, indicating its potential candidate material for soft tissue engineering.

Silk scaffolds connected with different naturally occurring biomaterials for prostate cancer cell cultivation in 3D.

In the present work, different biopolymer blend scaffolds based on the silk protein fibroin from Bombyx mori (BM) were prepared via freeze-drying method. The chemical, structural, and mechanical properties of the three dimensional (3D) porous silk fibroin (SF) composite scaffolds of gelatin, collagen, and chitosan as well as SF from Antheraea pernyi (AP) and the recombinant spider silk protein spidroin (SSP1) have been systematically investigated, followed by cell culture experiments with epithelial prostate cancer cells (LNCaP) up to 14 days. Compared to the pure SF scaffold of BM, the blend scaffolds differ in porous morphology, elasticity, swelling behavior, and biochemical composition. The new composite scaffold with SSP1 showed an increased swelling degree and soft tissue like elastic properties. Whereas, in vitro cultivation of LNCaP cells demonstrated an increased growth behavior and spheroid formation within chitosan blended scaffolds based on its remarkable porosity, which supports nutrient supply matrix. Results of this study suggest that silk fibroin matrices are sufficient and certain SF composite scaffolds even improve 3D cell cultivation for prostate cancer research compared to matrices based on pure biomaterials or synthetic polymers.

Development of a novel glucosamine/silk fibroin–chitosan blend porous scaffold for cartilage tissue engineering applications

Silk fibroin–chitosan blend is reported to be an attractive scaffold material for tissue engineering applications. In our earlier study, we developed a scaffold having an optimal silk fibroin–chitosan blend ratio of 80:20 and proved its potentiality for cartilage tissue engineering applications. Glucosamine is one of the major structural components of cartilage tissue. The present work investigates the effect of glucosamine components on the physicochemical and biocompatibility properties of this scaffold. To this end, varied amounts of glucosamine were added to silk fibroin–chitosan blend with the aim of improving various scaffold properties. The addition of glucosamine components did not show any significant change in physicochemical properties of silk fibroin–chitosan blend scaffolds. The composite scaffold showed an open pore structure with desired pore size and porosity. However, cell culture study using human mesenchymal stem cells derived from umbilical cord blood revealed an overall increase in cell supportive properties of glucosamine-added scaffolds. Cell viability, cell proliferation and glycosaminoglycan assays confirmed enhanced cell viability and proliferation of mesenchymal stem cells. Thus, this study demonstrated the beneficial effect of glucosamine on improving the cell supportive property of silk fibroin–chitosan blend scaffolds making it more potential for cartilage tissue regeneration. To the best of our knowledge, this is the first report on the study of glucosamine-added silk fibroin–chitosan blend porous scaffolds seeded with mesenchymal stem cells derived from umbilical cord blood.