Development Of Bone Scaffolds Research Articles

Mechanical properties of triply periodic minimal surface (TPMS) scaffolds: considering the influence of spatial angle and surface curvature.

Triply periodic minimal surface (TPMS) has a promising application in the design of bone scaffolds due to its relevance in bone structure. Notably, the mechanical properties of TPMS scaffolds can be affected by many factors, including the spatial angle and surface curvature, which, however, remain to be discovered. This paper illustrates our study on the mechanical properties of tissue scaffolds consisting of TPMS structures (Primitive and I-WP) by considering the influence of spatial angle and surface curvature. Also, the development of a novel model representative of the mechanical properties of scaffolds based on the entropy weight fuzzy comprehensive evaluation method is also presented. For experimental investigation and validation, we employed the selective laser melting technology to manufacture scaffolds with varying structures from AlSi10Mg powder and then performed mechanical testing on the scaffolds. Our results show that for a given porosity, the Gaussian curvature of the stretched TPMS structures is more concentrated and have a higher elastic modulus and fatigue life. At the spatial angle θ = 27°, the shear modulus of the primitive unit reaches its largest value; the shear modulus of the I-WP unit is positively correlated with the spatial angle. Additionally, it is found that the comprehensive mechanical properties of TPMS structures can be significantly improved after changing the surface curvature. Taken together, the identified influence of spatial angle and surface curvature and the developed models of scaffold mechanical properties would be of significant advance and guidance for the design and development of bone scaffolds.

Microwave sintering and characterization of robocasted HA, CNT-HA scaffold structures for bone regeneration applications

The application of additive manufacturing in the field of biomedical medical research is being widely explored, in the development of bone scaffolds with different architectures and desired properties. Robocasting, an extrusion-based additive manufacturing technique that can print a wide range of materials at a relatively lower cost has been adopted in this study. The 3D structure was realized by robocasting of hydroxyapatite (HA) incorporated with different loading percentages (0.5, 1, and 2 wt%) of multiwalled carbon nanotubes (MWCNTs). Carboxymethyl cellulose (CMC) is used as a binder for the development of ceramic slurries with desired viscoelastic properties. Microwave sintering of the developed scaffold structures in the argon (Ar) atmosphere was performed at different sintering temperatures, with a 5 min soaking time, and 3 LPM Ar flow rate. FESEM/EDS imaging and Raman spectroscopy analysis confirmed the retention of incorporated MWCNTs post-sintering. With an increase in sintering temperature, physical properties of the developed scaffold structures such as density and shrinkage were observed to increase whereas porosity was reduced. The better compressive strength was observed in samples sintered at 1100 °C. And a maximum compressive strength of 21.86 MPa was recorded for 0.5HAIF100 scaffold structures in comparison to other reported groups. The in vitro cell studies confirmed that the adopted percentages of MWCNTs were biocompatible and also capable of promoting osteogenic differentiation. The developed scaffolds also remained stable for about 28 days without undergoing degradation.

Noncytotoxic zinc-doped nanohydroxyapatite-based bone scaffolds with strong bactericidal, bacteriostatic, and antibiofilm activity.

Development of bone scaffolds that are nontoxic to eukaryotic cells, while revealing bactericidal activity still remains a huge challenge for the scientific community. It should be noted that only bacteriostatic (the ability of the biomaterial to inhibit the growth of bacteria) and bactericidal (the ability to kill >99.9% bacteria) activities have clinical importance. Unfortunately, many material scientists are confused with the microbiological definition of antibacterial action and consider biomaterials causing reduction in colony-forming units (CFUs) by 50-80% as promising antibacterial implants. The aim of this study was to synthesize three variants of Zn-doped hydroxyapatite (HA) nanopowder, which were characterized by different content of Zn2+ and served as a powder phase for the production of novel macroporous chitosan/agarose/nanoHA biomaterials with high antibacterial activity. Within this study, it was proven that the scaffold with a low zinc content (doping level 0.03mol for 1mol of HA; 0.2wt%) revealed the gradual and slow release of the Zn2+ ions, preventing against accumulation of high and toxic concentration of therapeutic agents and providing prolonged antibacterial activity. Moreover, developed biomaterial was nontoxic to human osteoblasts and showed anti-biofilm properties, bactericidal activity (> 99.9% of bacteria killed) against Staphylococcus epidermidis and Escherichia coli, significant antibacterial activity against Staphylococcus aureus (98.5% of bacteria killed), and also bacteriostatic activity against Pseudomonas aeruginosa. Thus, the developed Zn-doped HA-based bone scaffold has excellent antibacterial properties without toxicity against eukaryotic cells, being a promising biomaterial for biomedical applications to repair bone defects and prevent post-surgery infections.

Revealing the compressive and flow properties of novel bone scaffold structure manufactured by selective laser sintering technique.

Additive manufacturing is revolutionizing the field of medical sciences through its key application in the development of bone scaffolds. During scaffold fabrication, achieving a good level of porosity for enhanced mechanical strength is very challenging. The bone scaffolds should hold both the porosity and load withstanding capacity. In this research, a novel structure was designed with the aim of the evaluation of flexible porosity. A CAD model was generated for the novel structure using specific input parameters, whereas the porosity was controlled by varying the input parameters. Poly Amide (PA 2200) material was used for the fabrication of bone scaffolds, which is a biocompatible material. To fabricate a novel structure for bone scaffolds, a Selective Laser Sintering machine (SLS) was used. The displacement under compression loads was observed using a Universal Testing Machine (UTM). In addition to this, numerical analysis of the components was also carried out. The compressive stiffness found through the analysis enables the verification of the load withstanding capacity of the specific bone scaffold model. The experimental porosity was compared with the theoretical porosity and showed almost 29% to 30% reductions when compared to the theoretical porosity. Structural analysis was carried out using ANSYS by changing the geometry. Computational Fluid Dynamics (CFD) analysis was carried out using ANSYS FLUENT to estimate the blood pressure and Wall Shear Stress (WSS). From the CFD analysis, maximum pressure of 1.799 Pa was observed. Though the porosity was less than 50%, there was not much variation of WSS. The achievement from this study endorses the great potential of the proposed models which can successfully be adapted for the required bone implant applications.

Optimization and Fabrication of Customized Scaffold Using Additive Manufacturing to Match the Property of Human Bone

Additive manufacturing plays a major role in medical science. One of the applications is the development of bone scaffolds. During scaffold fabrication, obtaining the properties of the polyamide scaffolds to mimic the elastic properties of human subchondral bone is a challenging task. In order to overcome this challenge, the present numerical study validated by experimental routine allows optimizing, fabricating and automating the generation of open porous polyamide scaffolds. Human subchondral bone has an elastic modulus of 1.15 GPa and pore size of 800 μm which helps for cell ingrowth. The design parameters such as strut diameter (0.6-3 mm) and unit cell size (1.4-5 mm) were considered for this investigation. The optimized scaffold structure was fabricated using selective laser sintering method, one of the additive manufacturing (AM) processes and the structure was validated through uniaxial compression. Experimental test revealed a deviation in structural modulus of about 14, 10 and 17% for circular, square and hexagonal cross section, respectively. Optimized unit cell dimensions were found. The preliminary MTT (Methyl Thiazolyl diphenyl-Tetrazolium bromide) assay tests to evaluate the distributions of cells were performed, using in vitro perfusion culture experiments. It was found that the scaffold structure with square cross section has the maximum percentage of cell viability of 58.33%. A computer-aided design tool was developed using CATIA V5 Visual Basic program for modelling the bone scaffolds with better interconnectivity of unit blocks, porosity and compressive strength. This program facilitates automatic generation of optimized scaffold structure by providing necessary input parameters. The developed CAD tool was efficient enough to model the customized scaffold.

Tailoring surface properties of carbon nanofibers via oxidation and its influence on dental pulp stem cell viability of PCL/CNF composites

The effect of oxidation time on the surface chemical and morphological properties of carbon nanofibers (CNFs) and their suitability for use as a reinforcement agent in the development of bone scaffolds was assessed. The CNFs were modified using a 3:1 v/v mixture of concentrated sulfuric (H2SO4) and nitric acid (HNO3) for different periods of time. Several analytical techniques were used to characterize the oxidized CNF surface properties. Photoacoustic Fourier transform infrared spectroscopy (PAS-FTIR) showed the creation of carboxylic groups due to the acid treatments. Scanning electron microscopy images revealed differences in the nanofibers before and after acid treatment. The relationship between the CNF crystals and their defects when varying the oxidation time were determined by Raman spectroscopy. The CNF FTIR results, contact angle measurements, and dispersion tests showed the formation of carboxylic groups due to the oxidative treatment. The results confirmed the presence of microstructures with defects, as well as chemically active functional surface groups, such as carboxyls and hydroxyls. Furthermore, a composite was prepared using polycaprolactone (PCL) as a matrix and the CNF as the reinforcement. The storage module of the oxidized CNFs was improved with respect to the nonoxidized CNFs. Furthermore, the scaffolds of PCL with oxidized CNFs enhanced the cell proliferation.

Synthesis of hydroxyapatite from Labeo rohita fish scale for biomedical application

Abstract In the present research, hydroxyapatite (HAp) is derived from fish scales which are discarded as waste material. Scales of Labeo rohita fish has been calcined at 1000°C after acid treatment for HAp synthesis. The calcined powder is characterized using FTIR and XRD that confirms the formation of HAp. TGA shows the HAp is thermally stable between 800-900°C. SEM analysis reveals highly porous morphology of the derived HAp confirming its application in the development of bone scaffold. TEM analysis confirms the formation of polycrystalline micro HAp particles. The developed HAp can be a suitable biomaterial for orthopedic treatment.

Investigation of Porosity Relationship in Additive Manufactured Novel Bone Scaffold

Additive manufacturing (AM) is one the advanced process for building up a component layer by layer, with one layer of material was bonded to the previously laid layer using a 3D design data. In the field of medical science AM is very much useful in the development of Bone Scaffolds. The bone scaffold needs the good level of porosity for the cultivation of cells. In this work, an algorithm for a novel structure with the theme of flexible porosity was introduced. Scaffold models were developed using CATIA V5 for four different porosities. The novel structures made of Poly Amide (PA 2200) material were fabricated using a commercially available Selective Laser Sintering machine (SLS). The differences in scaffold theoretical and experimental porosities were investigated and the percentage of error was discussed.

Providing osteogenesis conditions to mesenchymal stem cells using bioactive nanocomposite bone scaffolds

Development of bone scaffolds with excellent osteogenic potential is highly important for stem cell-based bone engineering. Here we developed novel scaffolds made of poly(lactic acid) (PLA) biopolymer with bioactive glass nanocomponent. In vitro bone bioactivity and osteogenic potential of the nanocomposite scaffolds were determined using bone marrow mesenchymal stem cells. Glass nanocomponent was evenly embedded within the PLA matrix while preserving the scaffold pore structure. Simulated body fluid (SBF) test revealed rapid induction of bone mineral-like apatite over the surface of the nanocomposite scaffold, which was not readily observed in the PLA. Cells adhered well onto the nanocomposite scaffold and multiplied during culture period. Nanocomposite scaffold significantly stimulated alkaline phosphatase (ALP) activity and the expression of bone-associated genes (collagen I, ALP, osteopontin and osteocalcin) with respect to PLA. Western blot analysis confirmed the osteogenic protein level was also higher on the nanocomposite scaffold. Results suggest that the nanocomposite scaffolds provide favorable conditions for osteogenesis of MSCs and thus find potential uses in bone tissue engineering.

Fabrication of a hydroxyapatite scaffold for bone tissue regeneration using microstereolithography and molding technology

Recently, many groups have researched the reconstruction of bone tissue and the development of bone scaffolds using solid freeform fabrication technology. However, the capacity to produce three-dimensional hydroxyapatite (HA) scaffolds with a very accurate architecture is limited by difficulties in the manufacturing process. In this study, a HA scaffold with an accurate pore size of 300 ± 10 μm was fabricated using a microstereolithography (MSTL) system and molding technology. In addition, an agar-overlay test was performed to investigate the cytotoxicity of the fabricated scaffold.