Porous Bone Scaffolds Research Articles

Evaluation of microstructure and mechanical properties of magnesium alloy based porous bone substitutes

Orthopedic implants based on magnesium (Mg) have been found to be a prospective metallic biomaterial owing to its biocompatibility, biodegradability and similar mechanical properties with respect to natural human bone. However, owing to its accelerated degradation in physiological solution, application of pure Mg as implant material is limited. Besides, conventional metallic implants are non-porous and often lead to stress-shielding. To this end, this investigation has focused towards biomimicking the native human bone, by fabricating porous Mg alloy-based bone scaffolds. Mechanical properties were tuned by introducing calcium and zinc as alloying elements into Mg metal matrix. Uniform distribution of alloying elements, along with gradient porosity was observed by FESEM with EDX analysis. The developed porous samples were examined for mechanical performance, that revealed comparable and tunable mechanical properties similar to natural bone even after introduction of porosities, thereby signifying promising potential of the Mg-alloy based bone implants developed in this study.

Prediction of the effective elastic moduli of porous bone scaffolds: Analytical and computational studies

Bone scaffolds are porous structures that are used to repair, regenerate and restore the functions of damaged bone tissue. Scaffolds should have sufficient mechanical strength since they are subjected to different mechanical loadings as implanted in the defect site. Recently, there has been growing interest in the application of micromechanical approaches to estimate the effective mechanical properties of these structures. However, most of the micromechanical methods are originally proposed for dilute concentration condition in which all of the pores are isolated and they are not suitable for the structures like scaffolds with an interconnected network of pores. This paper presents the modified version of the Mori–Tanaka approach which is able to consider the interconnectivity between the pores and is completely appropriate for investigation of the mechanical behavior of the scaffolds. The validity of the developed relations is investigated via statistical finite element analysis. The effective moduli of the numerous scaffolds available in the literature are also computed using the suggested modifications. Comparison between the findings of this paper and published empirical studies shows that for the scaffolds with interconnected pore networks, using these modifications significantly improves the results in comparison with the case of using the classical Mori–Tanaka scheme.

Porous tantalum scaffolds: Fabrication, structure, properties, and orthopedic applications

Porous tantalum scaffolds have been developed and clinically utilized as superior implantable biomaterials for orthopedic applications owing to their exceptional corrosion resistance, biocompatibility, osteointegration, and osteoconductivity. Moreover, the biomimetic porous structure and mechanical properties of these scaffolds match those of human bone tissues. Over the past twenty years, the fabrication, structure and properties optimization, and application expansion of porous tantalum scaffolds have been advanced by emerging manufacturing technologies, characterization methodologies, and clinical utilization strategies. Combining our innovative work and over two hundred extant publications, we overview the fabrication, structure, properties, and orthopedic applications of porous tantalum bone scaffolds. Additive manufacturing has become a powerful and versatile technique for fabricating patient-specific and anatomy-matching porous tantalum bone implants with well-designed architectures. Additively manufactured tantalum scaffolds are deemed as new biomaterials for bone repair, as their microstructures and mechanical properties differ from those of bioimplants fabricated by traditional technologies. To understand the safety and effectiveness of these scaffolds for orthopedic applications, we must undertake basic scientific investigations, in vitro studies, pre-clinical studies, and clinical research. Biomechanical studies and porous structure design based on finite element analysis are additional hot topics in tantalum scaffold research.

Experimental measurement and simulation of mechanical strength and biological behavior of porous bony scaffold coated with alginate-hydroxyapatite for femoral applications

In the present study, the 3D printer method for fabricating porous bone scaffolds with Polylactic Acid (PLA) printed was used by Fused Deposition Modelling (FDM). Then, the prepared 3D scaffold coated with alginate composed with various amounts of Hydroxyapatite (HA) using the freeze-drying technique. After the fabrication of novel functional graded materials scaffold, the mechanical strength and biological behavior were investigated. The Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD) analysis used to characterize the morphology and phase characterization. The structure of the porous scaffold was simulated using the ABAQUS analysis method and their mechanical and physical properties were extracted. Also, strong antibacterial properties were observed for all samples with increasing HA nanoparticles against gram-positive and gram-negative bacterial suspensions. These bio-nano composites are compatible with the pH of the blood. In general, it was found that the most suitable bio-nano composite is the sample with 10 wt % HA nanoparticles. The elastic modulus increased from 350 MPa to 394 MPa with the addition of HA nanoparticles, while the porosity percentages decreased from 44 % to 36 %. The compressive strength increases from 25.2 MPa to 32.7 MPa with the addition of 30 wt% HA nanoparticles. The obtained results showed that the bio-nano composites prepared in this study were suitable for further development in bone substitutes with desirable mechanical properties. The alginate/HA material properties reported from the numerical approach, have an acceptable agreement with experimental results. Furthermore, the numerical study indicated that the scaffold compressive strength increases from 22.8 MPa (S1) to 31.2 MPa (S4) with the addition of 30 wt % HA nanoparticles. Nanoindentation test explains that the indenter penetration decreases from 82.163 nm to 69.338 nm with the addition of 30 wt% HA nanoparticles. As a consequence, PLA-alginate/20 wt % HA (S3) and, PLA-alginate/30 wt% HA (S4) have the best mechanical properties. Although due to lower biological advantages of S4 concerning S3, PLA-alginate/20 wt % HA (S3) chose as an appropriate bio-nanocomposite for orthopedic application.

Zn-substituted Mg2SiO4 nanoparticles-incorporated PCL-silk fibroin composite scaffold: A multifunctional platform towards bone tissue regeneration

Electrospun porous bone scaffolds are known to imitate the extracellular matrix very well and provide an environment through which the tissue formation is enhanced. Although polymeric scaffolds have a great potential in bone tissue regeneration, their weak bioactivity (bone bonding ability) and mechanical properties have left room for improvement. Therefore, the present study focused on the developing a ternary multifunctional platform composed of polycaprolactone (PCL)/silk fibroin (SF)/Zn-substituted Mg2SiO4 nanoparticles for bone tissue regeneration. This study is composed of two connected sections including synthesis and characterization of Mg(2-x)ZnxSiO4, x = 0, 0.5, 1, 1.5, 2 through surfactant-assisted sol-gel technique followed by incorporation of the nanoparticles into PCL/SF hybrid scaffold via electrospinning technique. The weight ratios of polymers and ceramic nanoparticles were optimized to reach desirable textural—porosity, pore size, and fiber diameter—and mechanical properties. Having optimized the ternary scaffold, it was then undergone different physical, chemical, and biological tests in vitro. A precise comparison study between the ternary (PCL/SF/ceramic nanoparticles), binary (PCL/SF), and pure PCL was made to shed light on the effect of each composition on the applicability of ternary scaffold. The overall results confirmed that the Mg1Zn1SiO4 nanoparticles-incorporated PCL/SF scaffold with fluorescence property was the one yielding the highest Young's modulus and desirable textural properties. The ternary scaffold showed improved biological properties making it a promising candidate for further studies towards bone tissue regeneration.

Influence of layer thickness and build orientation on compressive strength of 3D printed scaffolds prototypes

The research on fabrication of customised porous bone scaffolds through additive manufacturing has been gaining momentum since last couple of years. This paper presents an analysis of compressive strength (CS) of two slightly different calcium sulfate based proprietary materials namely, Zp150 and VisiJet PXL Core. The comparison is performed on different layer thickness (LT) and builds orientation (BO) of ZPrinter ®450 using full factorial design approach. Initially, a computer aided design (CAD) model of the porous scaffold with designed porosity is prepared in a CAD modelling software and then additive manufacturing is done on four different LT (0.089 mm, 0.101 mm, 0.112 mm and 0.125 mm) and three BO (along x-axis, y-axis and z-axis) of ZPrinter ®450. Analysis of CS reveals that prototypes made of VisiJet PXL Core material have shown a better strength in comparison with their Zp150 counterparts for similar LT and BO. In general, prototypes of both the materials printed along x-axis posses better CS for all the LT. Moreover, the prototype of VisiJet PXL Core material fabricated along x-axis on layer thickness 0.089 mm possesses highest (1.17 MPa) CS among all the prototypes.

Shape memory PLLA-TMC/CSH-dPA microsphere scaffolds with mechanical and bioactive enhancement for bone tissue engineering

Porous biodegradable bone scaffold is a remarkable strategy for bone-tissue engineering. It is well known that some basic requirements such as the biodegradabilty, biocompatibility, porous structure, surface properties, mechanical properties and plasticity of the scaffolds are vital for new bone formation. In this article, we adopted a low temperature method and poly (dopamine) coating strategy to fabricate porous shape-memory poly (L-lactide-co-trimethlyene carbonate)/calcium sulfate hemihydrate-poly (dopamine) microsphere scaffolds with uniform microstructure. Compared with PLLA-TMC microspheres, PLLA-TMC/CSH and PLLA-TMC/CSH-dPA microspheres have rougher surface and increased Tg. The mechanical properties and biodegradability of scaffolds were also tested in vitro, and the biocompatibility and osteoconductivity were monitored by CCK-8 and ALP activity assay using MC3T3-E1 cells. Strikingly, compared with PLLA-TMC scaffolds, PLLA-TMC/20CSH scaffolds possessed an enhanced initial compression modulus and higher degradation rate. Meanwhile, the compression modulus of all P/CSH scaffolds matched the cancellous bone during degradation period (103.04–623.75 MPa). Moreover, the PLLA-TMC/CSH-dPA microsphere scaffolds were non-toxic and contributed to cell adhesion. In summary, the prepared PLLA-TMC/CSH-dPA microsphere scaffold in this work is a promising approach for bone-tissue engineering.

3D printing and osteogenesis of loofah-like hydroxyapatite bone scaffolds

Repair of metabolic function in large bone defect remains a critical challenge, which largely depends on the osteogenic property of bone scaffold. Furthermore, microporous structure is one of the most critical factors that influence the osteogenic performance of bone scaffold. Therefore, it is an effective method to explore porous structures aiming at promoting osteogenesis. In this work, hydroxyapatite, the most abundant inorganic substance in bone tissue, was considered the research material. Furthermore, a natural loofah with high porosity and connectivity was selected as the bionic structure to reconstruct a porous bone scaffold based on 3D printing. Four types of loofah-like bone scaffolds were reconstructed and fabricated, and they all have an appropriate pore size and complex internal structure with a desirable porosity. According to the osteogenic ability analyses of micro-CT and histological morphometric, the BV/TV data of Type Ⅱ could reach 33%. The bone formation was found in pores and deep, rugged surfaces of scaffolds. The bionic bone scaffolds can promote in vivo osteogenesis, confirming the utility of our designed bionic scaffolds for bone regeneration.

Preparation and biological assessment of a ZrO2-based bone scaffold coated with hydroxyapatite and bioactive glass composite

Zirconia (ZrO2) bioceramics has superior stiffness, prominent fracture toughness and fracture strength. However, ZrO2 is almost bioinert material as an alternative scaffolds for repairing bone defects. In this paper, we prepared a porous ZrO2-based bone scaffold coated with hydroxyapatite (HA) and bioactive glass (BG) composite and optimized the quality hybrid proportion of HA and BGs composite coating and sintering temperature. The scaffold has a dense composite coating at the coating sintering temperature of 950 °C and HA content of 70% with Ca2SiO4 and β-TCP, HA and Ca10(PO4)6CO3 phases. The ZrO2 composite scaffold with HA-BG coating was capable of forming rich calcium and phosphorus deposits in the simulated body fluids. Its compression strength was superior to that of the porous ZrO2 scaffold. And the scaffold can promote proliferation of cultured mesenchymal stem cells and the adhesion and propagation of osteosarcoma MG-63 cells. The results exhibited that the excellent mechanical properties, biological activities and good cytocompatibility of the scaffold. Therefore, The composite scaffold represents a potential bone implant for future clinical applications.

Process parameter optimization for porosity and compressive strength of calcium sulfate based 3D printed porous bone scaffolds

Purpose This study aims to optimize the process parameters of ZPrinter® 450 for measured porosity (MP) and compressive strength (CS) of calcium sulfate-based porous bone scaffold using Taguchi approach. Design/methodology/approach Initially, a porous scaffold with smallest pore size that can be de-powdered completely is identified through a pilot study. Five printing parameters, namely, layer thickness (LT), build orientation (BO), build position (BP), delay time (DT) and binder saturation (BS), each at three levels have been optimized for MP and CS of the fabricated scaffolds using L27 orthogonal array (OA), signal-to-noise ratio and analysis of variance (ANOVA). Findings The scaffolds with 600 µm pores could be de-powdered completely. Optimum levels of parameters are LT2, BO1, BP2, DT1 and BS1 for MP and LT1, BO1, BP2, DT1 and BS2 for CS. The ANOVA reveals that the BS (49.12%) is the most and BP (8.34%) is the least significant parameter for MP. LT (50.84%) is the most, BO (33.79%) is second most and DT (2.59%) is the least significant parameter for CS. Taguchi confirmation test and linear regression models indicate a good agreement between predicted and experimental values of MP and CS. The experimental values of MP and CS at the optimum levels of parameters are found 38.12% and 1.29 MPa, respectively. Originality/value The paper presents effect of process parameters of ZPrinter® 450 on MP and CS of calcium sulfate-based porous scaffolds. Results may be used as guideline for powder bed binder jetting three-dimensional printing of ceramic scaffolds.

Process capability analysis of binder jetting 3D printing process for fabrication of calcium sulphate based porous bone scaffolds

ABSTRACT This study aims at investigating the process capability of a 3D printer for the fabrication of porous bone scaffolds. Initially, a suitable material is identified by optimising process parameters of a 3D printer using a full factorial design approach. Then, dimensional deviation and tolerance grades of the scaffold samples are calculated. Finally, process capability indices are evaluated and the process is recentred. Out of two materials under study, VisiJet PXL Core powder is found to provide better dimensional accuracy. Tolerance grades of the samples are found to be ranged from IT3 to IT10. Maximum dimensional deviation before and after centring the process is found to be 0.47% and 0.44%, respectively. Process capability indices Cp and Cpk are greater than 1 and close to industry benchmark (Cpk ≥1.33). This indicates the process is under statistical control and capable of fabricating porous bone scaffolds suitable for in vitro or in vivo bone tissue engineering applications.

Fabrication of Biomolecule-Loaded Composite Scaffolds Carried by Extracellular Matrix Hydrogel

Fabrication of multifunctional scaffolds with biomimicking physical and biological signals play an important role in enhancing tissue regeneration. Multifunctional features come from the composite scaffold with various bioactive molecules. However, simple, biocompatible, and controllable hybridization strategy is still lacking. In this study, we leverage naturally derived extracellular matrix (ECM) as chemically controllable hydrogel carrier to effectively load functional biomolecules. The use of ECM hydrogel takes advantage of both native functionality of ECM components and tunability of hydrogel in controlling release of loaded molecules. As a proof of concept, porous acellular bone scaffold was selected as the solid pristine scaffold to be composited with BMP-2 and VEGF, which are loaded by spinal cord-derived ECM (SC-ECM) hydrogel. Crosslinking degree of SC-ECM hydrogel is tuned by changing genipin concentration, which renders the control over release kinetics of BMP-2 and VEGF. The mechanical strength of scaffold maintained after hybridization and is not significantly decreased in wet condition. In vitro evaluations of scaffolds cocultured with osteoblasts and mesenchymal stem cells (MSCs) demonstrate the biocompatible and bioactive features resulting from the composite scaffolds. Evidenced by alkaline phosphatase test, immunofluorescence, and real-time polymerase chain reaction, differentiation of MSCs towards osteoblast lineage is significantly enhanced by composite scaffolds. Therefore, our strategy in fabricating composite scaffold enabled by biomolecule-loaded ECM hydrogel holds great promise in regenerating diverse tissue types by appropriate combinations of solid pristine scaffolds, ECM, and bioactive molecules. Impact statement We developed a bioactive molecule (e.g., growth factor, protein) loading method using extracellular matrix hydrogel as a carrier. It brings a new strategy to fabricate composite scaffolds with unique biofunctions.

Polyetheretherketone and Its Composites for Bone Replacement and Regeneration.

In this article, recent advances in the development, preparation, biocompatibility and mechanical properties of polyetheretherketone (PEEK) and its composites for hard and soft tissue engineering are reviewed. PEEK has been widely employed for fabricating spinal fusions due to its radiolucency, chemical stability and superior sterilization resistance at high temperatures. PEEK can also be tailored into patient-specific implants for treating orbital and craniofacial defects in combination with additive manufacturing process. However, PEEK is bioinert, lacking osseointegration after implantation. Accordingly, several approaches including surface roughening, thin film coating technology, and addition of bioactive hydroxyapatite (HA) micro-/nanofillers have been adopted to improve osseointegration performance. The elastic modulus of PEEK is 3.7–4.0 GPa, being considerably lower than that of human cortical bone ranging from 7–30 GPa. Thus, PEEK is not stiff enough to sustain applied stress in load-bearing orthopedic implants. Therefore, HA micro-/nanofillers, continuous and discontinuous carbon fibers are incorporated into PEEK for enhancing its stiffness for load-bearing applications. Among these, carbon fibers are more effective than HA micro-/nanofillers in providing additional stiffness and load-bearing capabilities. In particular, the tensile properties of PEEK composite with 30wt% short carbon fibers resemble those of cortical bone. Hydrophobic PEEK shows no degradation behavior, thus hampering its use for making porous bone scaffolds. PEEK can be blended with hydrophilic polymers such as polyglycolic acid and polyvinyl alcohol to produce biodegradable scaffolds for bone tissue engineering applications.

Effect of Printing Parameters on Compressive Strength of Additively Manufactured Porous Bone Scaffolds Using Taguchi Method

This paper presents Taguchi's design of experiment approach to optimize the process parameters of a 3D printer for enhancing the compressive strength (CS) of porous bone scaffolds. Effect of four process parameters, namely layer thickness (LT), build orientation (BO), build position (BP) on platform, and delay time (DT) on CS of calcium sulfate-based bone scaffolds, have been studied experimentally. L9 orthogonal array (OA) is chosen to design and perform the experiments. LT: 89 µm, BO: 0o, BP: Middle, and DT: 200 ms are the optimum values of parameters obtained by S/N ratio analysis. LT is most significant (48.18%), BO is slightly less significant than LT (45%), BP is little significant (6.39%), and DT is found non-significant (0.43%) as per the ANOVA analysis. A linear regression model is developed to predict the CS of fabricated scaffolds. The developed model is found adequate with 94.4% and 93%, R-sq and R-sq(adj) values, respectively. The confirmation test results in a maximum difference of 8.18% between experimental and predicted values of CS.

Architectural design of Ti6Al4V scaffold controls the osteogenic volume and application area of the scaffold

The geometry of porous bone scaffolds has an important effect on its bone ingrowth, but there is still a lack of in-depth research on this aspect. This study establishes a curved structure and a strut structure with a porosity of 65% and a pore size of 650 μm. The rabbit femoral condyle implants were used to assess the bone ingrowth. The pressure cloud chart and the velocity streamline inside the scaffold structure were calculated by computational fluid dynamics (CFD). The results show that the osteogenic property of a curved structure is better than that of a strut structure, but the mechanical property is not as good as that of the strut structure. The velocity streamline and velocity difference inside the scaffold structure has a great influence on bone ingrowth. Under the same condition, the smaller the fluid velocity difference inside the scaffold structure, the larger the fluid flow area, and the better the bone tissue growth. Studies have shown that the geometry of the bone scaffold can be optimized according to different implantation sites to meet the requirements of different implantation sites.

Fabrication and properties of CaSiO3/ Sr3(PO4)2 composite scaffold based on extrusion deposition

In recent years, 3D printing technology has been increasingly used to fabricate porous bone scaffolds for treating bone tissue defects. Calcium silicate (CS) is a bioceramic material with broad application prospects, but the characteristics of poor sintering performance and fast degradation have limited its further application. In this paper, porous CS scaffolds with different proportions of strontium phosphate (Sr3(PO4)2) were formed by pneumatic extrusion deposition. Experiments showed that the Sr element replaced the Ca element in CaSiO3, which altered the crystal structure of CaSiO3, changed its physical and chemical properties, and improved the sintering property of CS ceramics. At the same time, the substituted Ca element formed Ca3(PO4)2. After mixing Ca3(PO4)2 and CaSiO3, the grain of CaSiO3 was refined and the sintering property was improved. Because of this dual role, the Sr element improved the sintering property of CaSiO3 ceramics and delayed the degradation of CS ceramics. Moreover, cell experiments showed that the addition of the Sr element had a positive effect on cell proliferation and differentiation.

Mechanical performance of additively manufactured pure silver antibacterial bone scaffolds

Implant infection is a serious complication resulting in pain, mortality, prolonged recovery, and antimicrobial resistance (AMR). Reducing the risk-of-infection associated with tissue implants require imminent attention, where pure silver (Ag) offers enormous potential. However, the printability, mechanical performance nor microbial resistance of additively manufactured (AM) pure Ag is unavailable in literature. This is critical as Ag is thought to play a vital role in the development of AM patient-specific infection resistant implants in the decade to come. The study therefore additively manufactured 99.9% pure-Ag through selective laser melting (SLM) and systematically investigates its mechanical performance. The validated SLM process parameters were then used to conceive two fully porous bone scaffold each at approximately 68 and 90% (wt.) porosity. While the study brings to attention the potential defects in SLM pure-Ag through X-ray nanotomography (X-ray nCT), the mechanical properties of porous Ag scaffolds were found to be similar to cancellous bone. The study achieved the highest SLM pure-Ag density of 97% with Young’s modulus (E), elastic limit (σe), yield strength (σy), ultimate strength (σult) and ultimate strain (εult) in the range of 15.5–17.8 GPa, 50.7–57.7 MPa, 57.6–67.2 MPa, 82.4–95.9 MPa and 0.07–0.10 respectively. The antimicrobial efficacy of printed silver was tested against the common implant infection-causing Staphylococcus aureus and led to 90% and 99.9% kill in 4 and 14 h respectively. The study, therefore, is a first step towards achieving a new generation Ag-based AM infection resistant porous implants.

Relationship between the morphological, mechanical and permeability properties of porous bone scaffolds and the underlying microstructure.

Bone scaffolds are widely used as one of the main bone substitute materials. However, many bone scaffold microstructure topologies exist and it is still unclear which topology to use when designing scaffold for a specific application. The aim of the present study was to reveal the mechanism of the microstructure-driven performance of bone scaffold and thus to provide guideline on scaffold design. Finite element (FE) models of five TPMS (Diamond, Gyroid, Schwarz P, Fischer-Koch S and F-RD) and three traditional (Cube, FD-Cube and Octa) scaffolds were generated. The effective compressive and shear moduli of scaffolds were calculated from the mechanical analysis using the FE unit cell models with the periodic boundary condition. The scaffold permeability was calculated from the computational fluid dynamics (CFD) analysis using the 4×4×4 FE models. It is revealed that the surface-to-volume ratio of the Fischer-Koch S-based scaffold is the highest among the scaffolds investigated. The mechanical analysis revealed that the bending deformation dominated structures (e.g., the Diamond, the Gyroid, the Schwarz P) have higher effective shear moduli. The stretching deformation dominated structures (e.g., the Schwarz P, the Cube) have higher effective compressive moduli. For all the scaffolds, when the same amount of change in scaffold porosity is made, the corresponding change in the scaffold relative shear modulus is larger than that in the relative compressive modulus. The CFD analysis revealed that the structures with the simple and straight pores (e.g., Cube) have higher permeability than the structures with the complex pores (e.g., Fischer-Koch S). The main contribution of the present study is that the relationship between scaffold properties and the underlying microstructure is systematically investigated and thus some guidelines on the design of bone scaffolds are provided, for example, in the scenario where a high surface-to-volume ratio is required, it is suggested to use the Fischer-Koch S based scaffold.

Manufacturability, Mechanical Properties, Mass-Transport Properties and Biocompatibility of Triply Periodic Minimal Surface (TPMS) Porous Scaffolds Fabricated by Selective Laser Melting

Selective laser melting is a promising additive manufacturing technology for manufacturing porous metallic bone scaffolds. Bone repair requires scaffolds that meet various mechanical and biological requirements. This paper addresses this challenge by comprehensively studying the performance of porous scaffolds. The main novelty is exploring scaffolds with different porosities, verifying various aspects of their performance and revealing the effect of their permeability on cell growth. This study evaluates the manufacturability, mechanical behaviour, permeability and biocompatibility of gyroid scaffolds. In simulations, mechanical behaviour and permeability exhibited up to 56% and 73% accuracy, respectively, compared to the experimental data. The compression and permeability experiments showed that the elastic modulus and the permeability of the scaffolds were both in the range of human bones. The morphological experiment showed that manufacturing accuracy increased with greater designed porosity, while the in vitro experiments revealed that permeability played the main role in cell proliferation. The significance of this work is improving the understanding of the effect of design parameters on the mechanical properties, permeability and cell growth of the scaffolds, which will enable the design of porous bone scaffolds with better bone-repair effects.

Effect of different CaSO4 contents on CaSiO3‐CaSO4 porous composite bone scaffolds by 3D gel‐printing

AbstractPorous CaSiO3‐CaSO4 composite scaffolds were successfully prepared by 3D gel‐printing (3DGP) technology in this study. In order to further improve the degradation performance of pure CaSiO3 scaffolds, the effect of different CaSO4 doping contents on CaSiO3‐CaSO4 composite scaffolds was studied. The results show that when the porous composite scaffolds were placed in simulated body fluid (SBF) for 5 weeks, the weight loss rate was 2.41% (CaSiO3‐1%CaSO4), 3.97% (CaSiO3‐3%CaSO4), 4.18% (CaSiO3‐5%CaSO4), 6.87% (CaSiO3‐7%CaSO4), and 12.93% (CaSiO3‐9%CaSO4), respectively, which could be concluded that CaSO4 doping has a significant effect on improving the biodegradability of CaSiO3 scaffolds. And CaSO4 doping can also effectively improve the compressive strength of composite scaffolds and that of CaSiO3‐3%CaSO4 composite scaffolds was tested as 54.67 MPa, and the shrinkage rate of porous composite scaffolds was nearly 11.4%, which meets the application requirements of bone repairing engineering.