Fabrication of composition-graded collagen/chitosan–polylactide scaffolds with gradient architecture and properties

Chitosan–polylactide (CH–PLA) copolymers with various polylactide percentages changing from around 14 to 40 wt% were synthesized. CH–PLAs were then blended with type-II collagen to fabricate layered collagen/CH–PLA scaffolds that are potentially suitable for the applications in articular cartilage repair. Based on combinatorial processing techniques involving layer-superposition, thermal melting and freeze-drying, two types of stratified collagen/CH–PLA scaffolds were built. The content of collagen inside the scaffolds altered from the top layer to the bottom layer in a trend contrary to that of chitosan. One of them was fabricated using tripolyphosphate (TPP) as a single crosslinker and another type of scaffold was constructed via a dual-crosslinking pathway using TPP and genipin as two crosslinkers in a designated order. These collagen/CH–PLA scaffolds were found to have graded average pore-size and porosity, gradient swelling index and layer-dependent compressive modulus. The resulting scaffolds were thus partially similar to the articular cartilage extracellular matrix in composition, structure and property. In vitro cell culture on some optimized collagen/CH–PLA scaffolds for a period of time up to 3 weeks showed that the scaffolds were able to well support the growth of the seeded cells, suggesting that these collagen/CH–PLA scaffolds have promising potential for articular cartilage repair.     

Bioactive monetite‐containing whisker‐like fibers reinforced chitosan scaffolds

The aim of this work was to develop bioactive chitosan scaffolds reinforced with monetite‐containing whisker‐like fibers. The fibers synthesized by homogeneous precipitation were characterized as monetite/hydroxyapatite short fibers (MAFs), using XRD, FTIR and SEM. The pure chitosan and MAFs/chitosan composite scaffolds were produced by freeze‐drying, and characterized with respect to porosity, pore size, swelling behavior, compressive strength and modulus, and in vitro bioactivity. The incorporation of MAFs in chitosan matrices led to increase the pore size, according to the evaluation by FE‐SEM, and decrease the porosity of composite scaffolds. The swelling ratio decreased as MAFs content of scaffolds increased. The compressive strength and modulus of scaffolds were improved by an increase in MAFs content. The noncross‐linked scaffolds with a chitosan: MAFs weight ratio of 1:1 (CW3) showed a porosity of 75.5%, and the strength and modulus of 259 kPa and 2.8 MPa in dry state, respectively. The crosslinking by glutaraldehyde resulted in improved mechanical properties. The strength and modulus of cross‐linked CW3 scaffolds in wet state reached to 345 kPa and 1.8 MPa, respectively. The in vitro bioactivity of the reinforced scaffolds, evaluated by FE‐SEM/EDS, XRD, and ATR‐FTIR, was confirmed by the formation of a carbonated apatite layer on their surfaces when they soaked in simulated body fluid (SBF). The results of this initial study indicate that the monetite‐containing whisker‐like fibers may be an appropriate reinforcement of chitosan scaffolds.     

溶液插层法制备PLA/HTCC-MMT纳米复合材料及其性能表征

以壳聚糖(CTS)和新疆地产蒙脱土(MMT)为原料制备了壳聚糖季铵盐改性蒙脱土(HTCC-MMT),通过溶液插层法制备了聚乳酸(PLA)/HTCC-MMT纳米复合材料。利用X射线衍射仪(XRD)、傅里叶红外光谱仪(FT-IR)、扫描电子显微镜(SEM)、热重分析仪(TG)等对其微观结构、力学性能、热稳定性及降解性进行了表征和分析。结果表明:HTCC-MMT用量达到5%时,PLA/HTCC-MMT纳米复合材料的力学性最佳;HTCC-MMT的加入使PLA/HTCC-MMT纳米复合材料热稳定性得到了提高加,快了PLA的降解。     

Two-step modification process to improve mechanical properties and bioactivity of hydroxyfluorapatite scaffolds

Porous ceramic scaffolds are synthetic implants, which support cell migration and establish sufficient extracellular matrix (ECM) and cell-cell interactions to heal bone defects. Hydroxyapatite (HA) scaffolds is one of the most suitable synthetic scaffolds for hard tissue replacement due to their bioactivity, biocompatibility and biomimetic features. However, the major disadvantages of HA is poor mechanical properties as well as low degradability rate and apatite formation ability. In this study, we developed a new method to improve the bioactivity, biodegradability and mechanical properties of natural hydroxyfluorapatite (HFA) by applying two-step coating process including ceramic and polymer coats. The structure, morphology and bioactivity potential of the modified and unmodified nanocomposite scaffolds were evaluated using transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and energy dispersive spectroscopy (EDS). The scaffold with optimized mechanical properties was HFA-30?wt%HT (HT stands for hardystonite) with a total porosity and pore size of 89?±?1 and 900–1000?µm, respectively. The compressive modulus and strength of HFA (porosity ~ 93?±?1) were improved from 108.81?±?11.12–251.45?±?12.2?MPa and 0.46?±?0.1–1.7?±?0.3?MPa in HFA-30?wt%HT sample, respectively. After applying poly(ε-caprolactone fumarate) (PCLF) polymer coating, the compressive strength and modules increased to 2.8?±?0.15 and 426.1?±?15.14?MPa, respectively. The apatite formation ability of scaffolds was investigated using simulated body fluid (SBF). The results showed that applying the hardystonite coating improve the apatite formation ability; however, the release of ions increased the pH. Whereas, modified scaffolds with PCLF could control the release of ions and improve the apatite formation ability as well.     

Anisotropic Chitosan Scaffolds Generated by Electrostatic Flocking Combined with Alginate Hydrogel Support Chondrogenic Differentiation

The replacement of damaged or degenerated articular cartilage tissue remains a challenge, as this non-vascularized tissue has a very limited self-healing capacity. Therefore, tissue engineering (TE) of cartilage is a promising treatment option. Although significant progress has been made in recent years, there is still a lack of scaffolds that ensure the formation of functional cartilage tissue while meeting the mechanical requirements for chondrogenic TE. In this article, we report the application of flock technology, a common process in the modern textile industry, to produce flock scaffolds made of chitosan (a biodegradable and biocompatible biopolymer) for chondrogenic TE. By combining an alginate hydrogel with a chitosan flock scaffold (CFS+ALG), a fiber-reinforced hydrogel with anisotropic properties was developed to support chondrogenic differentiation of embedded human chondrocytes. Pure alginate hydrogels (ALG) and pure chitosan flock scaffolds (CFS) were studied as controls. Morphology of primary human chondrocytes analyzed by cLSM and SEM showed a round, chondrogenic phenotype in CFS+ALG and ALG after 21 days of differentiation, whereas chondrocytes on CFS formed spheroids. The compressive strength of CFS+ALG was higher than the compressive strength of ALG and CFS alone. Chondrocytes embedded in CFS+ALG showed gene expression of chondrogenic markers (COL II, COMP, ACAN), the highest collagen II/I ratio, and production of the typical extracellular matrix such as sGAG and collagen II. The combination of alginate hydrogel with chitosan flock scaffolds resulted in a scaffold with anisotropic structure, good mechanical properties, elasticity, and porosity that supported chondrogenic differentiation of inserted human chondrocytes and expression of chondrogenic markers and typical extracellular matrix.     

Effects of formaldehyde solution and nanoparticles on mechanical properties and biodegradation of gelatin/nano β-TCP scaffolds

In this study, gelatin/beta tricalcium phosphate (β-TCP) nanocomposite scaffolds were prepared by solvent casting method. The cross-linking method was carried out by adding formaldehyde to gelatin. The microparticles of sodium chloride were used as porogen agent. Characterization of nano β-TCP was performed using XRD, FTIR, and SEM. Results showed that the size of the particles is about 100 nm with spherical morphology. In addition, the scaffold characterization was carried out using FTIR and SEM techniques. Observations showed a porous texture with pore size between 100 and 400 μm. The biodegradability and bioactivity evaluations of the scaffolds were done by immersing them in a simulated body fluid solution for different time periods. The biodegradability studies demonstrated a reduction in the degradation rate of gelatin/β-TCP nanocomposite scaffolds due to the presence of β-TCP nanoparticles. The obtained results of bioactivity tests confirmed the formation of apatite layer on the surface of the scaffolds. Furthermore, the effects of porosity, cross-linking agent, and β-TCP nanoparticles on the bending and compressive properties of the composite scaffolds were examined. According to the mechanical examinations of the scaffolds, the best bending and compressive properties occurred in the presence of 10 and 20 wt% of β-TCP nanoparticles, respectively. The appropriate mechanical properties and biodegradation rate for tissue engineering applications obtained at 1 g of the formaldehyde solution.     

Investigation of polyvinyl alcohol nanocomposite hydrogels containing chitosan nanoparticles as wound dressing

Polymeric hydrogels, water-swollen 3?D networks of the polymers, have found wide ranges of applications in the medical fields, such as wound care and wound dressing, in order to prevent infections. Prevention from microorganisms transfer in to the wounds is one of the ideal wound dressing duties of polyvinyl alcohol (PVA) hydrogels. In this study, at the start, under optimal conditions, nanoparticles of chitosan using ionotropic gelation method were synthesized and in the next step in order to achieve particles with a minimum size, they were evaluated by scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR). Then after to obtain a wound dressing with preferable properties, nanocomposite hydrogels using a combination of PVA and 5, 10 and 15?wt% chitosan nanoparticles were prepared through freezing-thawing cycles. The necessary features of PVA nanocomposite hydrogels for wound dressing were investigated. The dispersion state of nanoparticles and structure of samples were evaluated by SEM microscopy. The nanoparticle size and the nanoparticle size distribution of chitosan was determined using the dynamic light scattering test at the nanometer scale. The physical behavior of hydrogels such as swelling and gel fraction was studied and their mechanical properties were investigated by compressive test. Finally the antimicrobial test and biocompatibility as cell viability were carried out. The results proved that the PVA nanocomposite hydrogels fulfill the requirements of a good wound dressing with desirable characteristics such as favorable swelling and acceptable strength, excellent barrier against microbial penetration.     

Novel Fe2O3-doped glass /chitosan scaffolds for bone tissue replacement

In this study quaternary bioglass system (BG) SiO₂–CaO–Na₂O–P₂O₅ doped with Fe₂O₃ was prepared by the sol–gel method. Furthermore, 3D scaffolds were designed through blending Fe₂O₃ -doped bioglass with chitosan to obtain various compositions of scaffolds by the freeze-drying technique. The thermal behavior, morphological properties, porosity (%), mechanical properties and physicochemical properties of BG and scaffolds were evaluated by DSC/TGA, TEM, SEM, liquid displacement method, universal testing machine, XRD and FTIR. In addition, the in vitro bioactivity of the prepared scaffolds was studied in phosphate buffer saline (PBS) through the determination of PBS ions concentrations, as well as the degradation and the observation of precipitated calcium phosphate layer by SEM coupled with EDX and FTIR behavior. The cell viability of the prepared scaffolds was conducted against Baby Hamster Kidney fibroblasts (BHK-21) cell line. The presence of Fe₂O₃ decreased the T_g (from 513 to 390?°C) and the size decreased (from 20.89 to 50.81–13.92–27.87?nm). The scaffolds porosity (%) decreased upon Fe₂O₃ doping but the mechanical strength increased. Cell viability results for the designed scaffolds demonstrated acceptable cell viability compared with normal cells. Therefore, the designed scaffolds are promoted as regenerated materials that can be used for bone tissue replacement.     

Evaluation of mechanical behavior,bioactivity, and cytotoxicity of chitosan/akermanite-TiO2 3D-printed scaffolds for bone tissue applications

This report aimed to evaluate the mechanical behavior, bioactivity, and cytotoxicity of novel chitosan/akermanite-TiO₂ (CS/AK/Ti) composite scaffolds fabricated using the 3D-printing method. The morphological and structural properties of these scaffolds were characterized by Fourier transform spectroscopy (FTIR) and scanning electron microscopy (SEM). The mechanical behavior was examined by measuring the compressive strength, while the bioactivity was estimated in the simulated body fluid (SBF), and also the cytotoxicity of the scaffolds was assessed by conducting cell culturing experiments in vitro. It was found that the mechanical properties were considerably affected by the amount of TiO_2. The scaffolds had the possessed bone-like apatite forming ability, which indicated high bioactivity. Furthermore, L929 cells spread well on the surface, proliferated, and had good viability regarding the cell behaviors. The outcomes confirmed that the morphological, biological, and mechanical properties of developed 3D-composite scaffolds nearly mimicked the features of natural bone tissue. In summary, these findings showed that the 3D-printed scaffolds with an interconnected pore structure and improved mechanical properties were a potential candidate for bone tissue applications.     

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

Functionalized 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.     

Mechanical reinforcement of chitosan using unzipped multiwalled carbon nanotube oxides

In this paper, unzipped multiwalled carbon nanotube oxides (UMCNOs), obtained by oxidation unzipping multiwalled carbon nanotubes (MWNTs) were used as novel nanofillers for mechanical reinforcement of chitosan (CS) matrix. The UMCNOs/CS nanocomposite films with different amounts of UMCNOs were fabricated by solution-casting the mixtures of UMCNOs and CS acetic acid aqueous dispersions. The structures and mechanical properties of the nanocomposite films were characterized by XRD, FT-IR, SEM, and tensile tests. The results demonstrated that UMCNOs could be homogeneously dispersed throughout the chitosan matrix. Compared to neat chitosan, the UMCNOs/CS nanocomposite films showed ～105.9% increase in tensile strength from 69.3 to 142.7 MPa, and ～165.3% increase in Young’s modulus from 2.6 to 6.9 Gpa with the incorporation of only 0.2 wt% of UMCNOs into the chitosan matrix.     

Fabrication and performance of calcium phosphate cement/small intestinal submucosa composite bionic bone scaffolds with different microstructures

The microstructure of the tissue has a very important determining effect on its performance. Herein, two calcium phosphate cement (CPC)/small intestinal submucosa(SIS) composites bionic bone scaffolds with different microstructures were fabricated by rolling or/ and assembling method. The microstructure, 3D morphology, the crystal phase and mechanical properties of the scaffolds were investigated by micro CT, XRD, FIIR, SEM and electronic universal testing machines respectively. The results showed that the pore size of all scaffolds are in the range of 100–400?µm, which are beneficial to cells growth, migration, and tissue vascularization. Their porosity and the specific surface area were 14.53?±?0.76%, 8.74?±?1.38?m²/m³ and 32?±?0.58%, 26.75?±?2.69?m²/m³ separately. The high porosity and the large specific surface area can provide a larger space and contact area for cells adhesion and proliferation. Meanwhile, compressive strength of the scaffolds soaked were 10?MPa and 27?MPa, about 1.2 folds and 3.2 folds of the original scaffolds, respectively. The results are derived from different microstructures of the scaffolds and chemical bonds between SIS and new phases (hydroxyapatite), and the scaffolds performance steadily increased at near the physiological conditions. Finally, biocompatibility of the scaffolds was evaluated by CCK8, bionic microstructure scaffolds are no cytotoxicity and their biocompatibility is favorable. Based on the microstructure, compressive strength and cytotoxicity of the scaffolds, bionic Harvarsin microstructure CPC/SIS composite scaffold is expected to turn into a scaffold with the excellent properties of real bone.     

Preparation of Pure PLLA,Pure Chitosan,and PLLA/Chitosan Blend Porous Tissue Engineering Scaffolds by Thermally Induced Phase Separation Method and Evaluation of the Corresponding Mechanical and Biological Properties

The aim of this work was to prepare the scaffolds of pure poly (L-lactic acid) 3% (w/v), pure chitosan 3% (w/v), and PLLA/chitosan blend (1:5) 3% (w/v) using TIPS method and investigate their properties and application in tissue engineering. An in vitro degradation study of scaffolds showed the addition of chitosan to PLLA not only increased its degradation rate, but also slowed down its pH value reduction. Addition of chitosan to PLLA increased hydrophilicity, porosity, compressive properties, and cell viability of the scaffolds. The results indicate that among all scaffolds, the most appropriate candidate for tissue engineering is PLLA/chitosan blend.     

Preparation of elastic chitosan/poly(<Emphasis Type="SmallCaps">l</Emphasis>-lactide-co-ε-caprolactone) macroporous scaffolds by acetylation and particulate leaching

For soft tissue engineering applications, 3-D macroporous acetylated chitosan/poly(l-lactideco-ε-caprolactone) (PLCL) scaffolds were prepared by acetylation and particulate leaching using sodium acetate in an acidic water/dioxane solution. Acetylated 5 wt% chitosan/PLCL scaffold of 90% porosity was determined and confirmed through various tests. The physiochemical properties of acetylated chitosan/PLCL hybrid scaffolds were examined by measuring water contact angles, pore morphology and interconnectivity using scanning electron microscopy (SEM), and dye release testing. In addition, mechanical properties such as tensile strength and bending stress recovery for determining the elasticity of scaffolds were measured. The fibroblast cell line NIH-3T3 was used to test relative cell affinities for the acetylated chitosan/PLCL vs. normal chitosan/PLCL films and porous scaffolds. The acetylated chitosan/PLCL films and scaffolds showed a high initial cell adhesion after 4 h of cell culture and increased cell proliferation compared to that of the control. The acetylated chitosan/PLCL scaffolds produced by particulate leaching showed a highly porous structure and improved the biocompatibility and stability of chitosan compared to that of chitosan-coated PLCL scaffolds. Thus, these scaffolds may be very useful for a variety of tissue engineering applications.     

Effects of wood flour and chitosan on mechanical,chemical, and thermal properties of polylactide

Composites of polylactide (PLA, 100–60 wt%) and wood flour (0–40 wt%) were prepared to assess the effects of wood filler content on the mechanical, chemical, thermal, and morphological properties of the composites. The polysaccharide chitosan (0–10 wt%) was added as a potential coupling agent for the PLA‐wood flour composites. Addition of wood flour significantly increased the flexural modulus and the storage modulus of PLA‐wood flour composite, but neither the wood flour nor chitosan had an effect on the glass transition temperature (T_g). Fourier transform infrared spectra did not show any evidence of covalent bonding, but chitosan at the interface between wood and PLA is thought to have formed hydrogen bonds to PLA‐carbonyl groups. SEM images of fracture surfaces showed that fiber breakage was far more common than fiber pullout in the composites. No evidence of discrete chitosan domains was seen in SEM micrographs. When added at up to 10 wt% (based on wood flour mass), chitosan showed no significant effect on the mechanical, chemical, or thermal properties of the composites, with property changes depending on wood flour content only. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers.     

Mechanical and biological performance of rainbow trout collagen-boron nitride nanocomposite scaffolds for soft tissue engineering

We aim to investigate the potential of collagen extracted from rainbow trout for tissue engineering applications. In this regard, nanocomposite scaffolds based on the extracted collagen reinforced with various concentrations of boron nitride (BN) nanoparticles (0, 3, 6, 9, and 12 wt%) were developed. In addition, the role of various concentrations of BN nanoparticles and two-step cross-linking process on the physical and chemical properties of nanocomposite scaffolds were investigated. Our results demonstrated the isolation of Type I collagen with excellent thermal stability but with some structural and chemical differences compared to other sources. The synergic role of BN nanoparticles and two-step cross-linking process resulted in a noticeable improvement in the mechanical properties of collagen-BN scaffolds. Noticeably, incorporation of 6 wt% BN along with a two-step cross-linking process significantly increased the compressive strength (9.5 times) and elastic modulus (four times) of the collagen scaffold. Besides, nanocomposite scaffolds significantly improved proliferation and spreading of MG-63 cell line, confirming their biocompatibility. The results suggested that the incorporation of BN nanoparticles along with a two-step cross-linking process not only could promote the mechanical and thermal performances of collagen scaffolds, but also enhanced high cell viability, and proliferation supporting their potential in tissue engineering applications.     

Fabrication and Characterization of Multicomponent Polysaccharide/Nanohydroxyapatite Composite Scaffolds

Carrageenan–hyaluronic acid/nanohydroxyapatite/microcrystalline cellulose composite scaffolds with various amounts of microcrystalline cellulose content (from 0 to 60?wt%) were prepared using freeze-drying method. The results showed highly porous (from 94.0?±?1.09 to 85.0?±?1.05%) composite scaffolds with high water-uptake capacity, average pore size ranging 200–650?µm, and improved mechanical properties (in dry and wet states). Additionally, cytocompatibility of composite scaffolds was evaluated by in vitro culture of osteoblast (MC3T3-E1) cells for 1 and 3 days of incubation and demonstrated good cell adhesion, infiltration, and proliferation. Thus, as-obtained composite scaffolds may have promising application in low-loading bone tissue engineering applications.     

Evaluation of poly(L-lactide) and chitosan composite scaffolds for cartilage tissue regeneration

The present study delineates the development of chitosan and poly(L-lactide) (PLLA) scaffolds cross-linked using a mixture of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC), n-hydroxysuccinimide (NHS), and chondroitin sulfate (CS) for cartilage tissue engineering applications. Chitosan and PLLA were varied in concentration for developing scaffolds and prepared by freeze-drying method. The various scaffolds were studied using scanning electron microscopy (SEM), porosity by mercury intrusion porosimeter, and the molecular interactions among polymers using Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) studies. Differential scanning calorimetry was used to predict the thermal properties of the scaffolds. The mechanical properties of the scaffolds were studied using static mechanical tester. The ability of the scaffolds to support chondrocyte proliferation was also studied. The microscopy suggests that the pore size of the scaffolds varied with the composition in the range of 38–172 μm and the porosities in the range of 73–93%. The XRD and the FTIR studies suggested that an alternation in the composition of the scaffolds altered the molecular interactions among the scaffold components. An increase in the chitosan content enhanced the swelling property. The degradation of the scaffolds was least when the proportion of chitosan and PLLA was in the ratio of 70:30. The in vitro cell proliferation study suggested that the developed scaffolds were able to support chondrogenesis, the glycosaminoglycan (GAG) content of the mature chondrocyte was 40 μg/ml and the viability was approximately 90%. Hence, the so designed scaffolds may be tried for cartilage tissue engineering applications.     

Compressive and flexural properties of novel polylactic acid/hydroxyapatite/yttria-stabilized zirconia hybrid nanocomposite scaffold

The mechanical property is a crucial factor in the design of bone tissue engineering scaffolds. In the current study, novel PLLA (Poly-L-lactic acid)–Hydroxyapatite (HA)–yttria-stabilized zirconia (YSZ) nanocomposite scaffold with various compositions was prepared and characterized. The effect of HA and YSZ contents on the mechanical behavior of the resultant composites was investigated. TEM micrograph revealed that HA particles are needle-like in shape and nano in size. Scanning electron microscopy (SEM) micrograph also showed that YSZ powder is in granule form and submicron size. SEM disclosed that all scaffolds had a highly interconnected porous structure and X-ray diffractometry revealed that there were some molecular interactions between PLA (Polylactic acid), HA, and YSZ in the composites. The results depicted that introducing YSZ to the nanocomposite leads to a significant increase in compressive strength, modulus, and densification strain. In addition, flexural strength and modulus showed an upward trend by adding YSZ particles to scaffolds. It should be noted that PLA–20%HA–20%YSZ indicates the highest strength and modulus in both compression and bending tests, though, it did not demonstrate the proper strain compared to other scaffolds. Thus, PLA–15%HA–15%YSZ has been reported as the best candidate due to appropriate strength and strain. Also, energy absorption in nanocomposites showed an upward trend by increasing the amount of YSZ particles. It was found that the strength of samples was declined after being soaked in simulated body fluid. However, scaffolds with HA underwent more decrease in strength compared to samples containing YSZ.     

Fabrication of a poly(ɛ‐caprolactone)/starch nanocomposite scaffold with a solvent‐casting/salt‐leaching technique for bone tissue engineering applications

A series of nanocomposite scaffolds of poly(?‐caprolactone) (PCL) and starch with a range of porosity from 50 to 90% were fabricated with a solvent‐casting/salt‐leaching technique, and their physical and mechanical properties were investigated. X‐ray diffraction patterns and Fourier transform infrared spectra confirmed the presence of the characteristic peaks of PCL in the fabricated scaffolds. Microstructure studies of the scaffolds revealed a uniform pore morphology and structure in all of the samples. The experimental measurements showed that the average contact angle of the PCL/starch composite was 88.05 ± 1.77°. All of the samples exhibited compressive stress/strain curves similar to those of polymeric foams. The samples with 50, 60, 70, and 80 wt % salt showed compressive‐load‐resisting capabilities in the range of human cancellous bone. With increasing porosity, a significant decrease in the mechanical properties of the scaffolds was observed. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43523.