A numerical study on mechanical and permeability properties of novel design additive manufactured Titanium based metal matrix composite bone scaffold for bone tissue engineering

Abstract

A novel design was developed for extrusion based additive manufacturing (robocasting) of bone scaffolds and a numerical study was carried out to find the optimal design to develop a bone scaffold for critical bone defect treatments. Initially, Representative Volume Analysis (RVE) analysis was carried out to predict the Young’s modulus (E) of Titanium + Calcium Silicate and Titanium + Hydroxyapatite composites. The RVE analysis outputs were used to find out the E value of various bone scaffold designs and material compositions. The novel stepped design could be used to tailor the mechanical and biological properties of the scaffold by altering the contact support area between strands and changing the pore size, shape and orientation to control the permeability and nutrient transportation. The test revealed that some of the designed scaffolds are suitable for developing scaffolds for cortical bone defects as the E value lies between 10 and 30 GPa. The CFD analysis indicated that some designs do not possess the permeability required for a scaffold to aid nutrient transportation which is ideally between 1.5 × 10⁻⁹ and 5 × 10⁻⁸ m². A sample model was printed and sintered in an argon atmosphere using a microwave furnace to check the feasibility of the process.

Keywords

Bone scaffolds bone tissue engineering critical bone defects RVE FEA CFD

Introduction

The treatment of critically sized bone defects has been a clinical challenge since it is not easy to reconstruct the part functionally and aesthetically.¹ Tissue engineered bones are gaining popularity as a technically feasible solution.² Autografts, allografts, and xenografts are the traditional treatment methods and autografts are considered as the gold standard in bone treatments. However, donor site morbidity, multiple surgical procedures, possible blood loss and scarcity of resources demand better treatment methods.^3–5 The rapid progress achieved by Additive Manufacturing (AM) has significantly influenced and contributed to the Bone Tissue Engineering (BTE) research. The extrusion process like Robocasting not only develops porous scaffolds to mimic the bone geometry but also gives the freedom to choose biocompatible and bioactive materials. This technique also incurs lower cost unlike the powder bed fusion AM processes like Selective Laser Melting (SLM) and Selective Laser Sintering (SLS).^6,7 Using Additive manufacturing techniques, researchers were able to develop artificial blood vessels, bones and hearts and successfully implant them inside the human body.⁸

There is no single material which can fulfil the physical, mechanical and biological properties of the human bone alone. Hence, composite scaffolds are being investigated to match the bone properties.⁹ Built-in porous designs are used to develop bone scaffolds to reduce Young’s modulus mismatch and eliminate the stress shielding effect.¹⁰ While large pores aid in cell penetration, small pores have better cell deposition. However, moderate pore sizes are better for cell differentiation which is critical for bone regeneration. A pore size of 650 µm produced the best bone ingrowth and the CFD analysis indicates that this pore size has high permeability and minimum velocity difference which is conducive to bone regeneration.^11,12 Another factor that influences bone regeneration is the age and health condition of the patient. If the patient is old or the defect occurs due to a deficiency of nutrients could lead to more healing time. Vascularization and angiogenesis are slower in elderly people and could change the biological process of bone healing and prolong the regeneration period.¹³

Commercially Pure Titanium (Ti) and its alloys are commonly used to treat bone defects for their excellent corrosion behaviour, low density, high strength, closeness to bone’s Young’s modulus and biocompatibility are better compared to other metals.^14,15 An In vivo experiment conducted by Naoya Taniguchi et al. revealed that porous Ti scaffolds can enhance cell proliferation and differentiation.¹⁶ However, the metal implants and scaffolds, including Ti and its alloys have poor osseointegration and osteoinductivity.¹⁷ These properties can be improved by incorporating bioceramics like Hydroxyapatite (HA: Ca₁₀(PO₄)₆(OH)₂)) which can mimic the natural bone to improve the osseointegration and osteoinductive materials like Calcium Silicate (CS: CaSiO₃).^18,19

Computer Aided Engineering software is used to design bone scaffolds to imitate the complex human bone shape which could influence the mechanical properties of the material.²⁰ The behaviour of the scaffold depends on the printing material, profile and printing method adopted. It is important to predict the physical and mechanical properties of the composites to design and develop the scaffolds with optimal properties. Computational analysis tools can predict the behaviour of composites if we can define a unit cell which could represent the final product. The representative Volume Element (RVE) method is a micro mechanic technique used to assess the properties of composites using homogeneous microstructural elements. RVE is defined as the smallest element that possesses all the properties and can represent a bulk heterogeneous material.^21,22 The RVE analysis output can be used to carry out the Finite Element Analysis (FEA) which can approximately provide the data on the mechanical properties of the designed scaffold to predict the macro mechanic performance. For a load bearing bone scaffold, it is important to analyse the behaviour under compressive load and the FEA of the scaffold can give an insight into the same before developing and physically testing.²³ Another property that influences scaffold performance is the permeability of the scaffold. The uninhibited flow and dispersal of blood to supply oxygen and nutrients through the pores is critical in bone ingrowth.^24–26 Computational fluid dynamics (CFD) can be used to predict the permeability of the designed shape using a CFD software.²⁷ It can also reveal other important parameters like Wall Shear stress and fluid pressure drop.²⁸

The recent developments in 3D printing technology have brought great opportunities to the world and the biomedical industry has been one of the main beneficiaries. In the case of bone tissue engineering, changes in lifestyles and an increase in average life expectancy are demanding better materials with biocompatibility and longevity.^6,9,29 At the same time, the cost involved in treating should be controlled as this is an expensive procedure at present. It can be made accessible by adopting cost-effective 3D printing methods like robocasting.³⁰ Robocasting is a layer-by-layer manufacturing method using inks or slurry prepared using binder and metal, ceramic or polymer powders.³¹ In this study, the possibility of reinforcing the Ti powder with bioactive ceramic powders like CS and HA is analysed. The RVE method is used to assess the resultant Young’s modulus of composites which is used to analyse the mechanical properties of the scaffold using the FEA technique. A CFD analysis is then carried out to validate the flow characteristics of the scaffold and the results along with the FEA result are analysed to find the optimum scaffold design and composite.

Methodology

The objective is to calculate the mechanical properties and permeability of the designed scaffolds using computational techniques as shown in Figure 1. The output from the RVE is used to analyse the scaffold properties in FEA while the flow field was extracted from the scaffold design for the CFD. The mechanical properties and the permeability were analysed to identify suitable scaffold designs.

Calculation of composite material properties using RVE

This analysis is carried out to find the effective Young’s Modulus of the metal-matrix composites reinforced with ceramics. The RVE method was carried out using the ABAQUS 2022 research edition. For the RVE analysis, a cube of dimension 600 µm was designed in ABAQUS software for the matrix Ti material which has a density of 4500 Kg/m³. A sphere with 313 µm diameter was designed to represent the CS and 300 µm diameter for HA. The difference in diameter is due to the difference in density of CS (2840 Kg/m³) and HA(3140 Kg/m³) and the composites are mixed based on wt% while RVE analysis is carried out based on Volume%. The CS will occupy around 15% of the composite volume whereas HA will occupy around 13% when the composite contains 10 wt% of the ceramic. Two corresponding spheres are randomly placed inside the cube for the 10 wt% TiCS samples and 10 wt% TiHA samples which will be mentioned as Ti90CS10 and Ti90HA10 in the article hereafter. Similarly, 4,6 8 and 10 spheres were inserted into the Ti cube to represent 20%, 30%,40% and 50 wt% of CS and HA in Ti matrix samples and the same naming pattern is followed as mentioned above. The Ti composite RVEs are shown in Figure 2. The physical and mechanical properties of the materials used in the RVE are listed in Table 1 below. A 30 µm displacement (5% strain) was given in the X axis and the Y and Z axes were restricted for linear and rotational movement.

Table 1.

Physical and mechanical properties of Ti, CS and HA.

Material	Density, ρ (Kg/m³)	Young’s modulus, E (GPa)	Poisson’s ratio, (µ)	Reference
Ti	4500	100	0.31	[48]
HA	3140	65	0.27	[59]
CS	2840	73.4	0.28	[60,61]

Analysis of scaffold design using FEA for mechanical properties

Development of scaffold designs

A cube of 10 mm in size was designed in Autodesk Fusion software. Later this design was imported into Simplify 3D software for slicing for a custom designed and developed Fabforge robocasting machine. Four different infill ratios, 25%, 50%, 75% and 100% with normal and a proposed novel design are sliced. The design obtained after slicing is modelled using Fusion 360. The novel design proposed changes the orientation of the strand by + 4° in every alternate layer. That is, a stepped design where strands are oriented in 0° and 90° in the first and second layers, 4° and 94° in the third and fourth layers, 8° and 98° in the fifth and sixth layers and so on and these models will be mentioned as 25S, 50S, 75S and 100S respectively in this article hereafter. This stepped design will ensure that there is more contact area for support between the stands compared to the normal design while maintaining a through hole from top to bottom for interconnected porosity. A normal design with 0° and 90° oriented stands in alternate layers is also designed which will be mentioned as 25N, 50N, 75N and 100N respectively hereafter. In an experiment to find out the best scaffold design for load bearing applications, Roohani-Esfahani et al. found that the hexagonal pattern with maximum contact area was better than the remaining models.³² Similarly, the stepped design is supposed to improve the mechanical properties of the scaffold since it has more contact surface area than the normal design between adjacent layers. While printing, as a result of gravity and self-weight, the adjacent strands will fuse and become oval-shaped.³³ Hence the strands were designed with 0.5 mm height and 0.7 mm for the 0.6 mm diameter nozzle. The Computer Aided Design (CAD) models and the top view of the design are shown in Figure 3.

Prediction of mechanical properties of scaffolds using FEA

A bone scaffold in the in vivo condition experiences a variety of mechanical loads on them such as tensile load, shear load, torsional load etc. However, compressive load is the predominant load acting on them which would determine the life cycle of the scaffold.^34–36 ABAQUS 2022 research edition is used to determine the effective compressive modulus, stress distribution etc. of the designed scaffolds using FEA.^23,37 The Young’s modulus value obtained from the RVE analysis is used as the material property for the composite scaffolds.

Firstly, a mesh convergence study was carried out using quadratic tetrahedral elements (C3D10) with mesh sizes ranging from 0.5 to 2.5 on the simplest and most complex designs, that is 25N and 100S with Ti as the material. A downward vertical displacement of 0.5 mm was given on the top face (Y-axis) of the scaffold while the bottom face was fixed for linear and rotational movements as shown in Figure 4 to find the effective Young’s modulus of the design. A moving rigid body was provided on the top surface to transfer the load smoothly to the scaffold while a fixed rigid body was provided at the bottom to calculate the reaction forces. These rigid bodies are used to increase the computational efficiency.^23,38

Also, a force of 1000 N was given in the same direction to predict the stress distribution and displacement experienced by the scaffold after implantation. The load 1000 N was selected to represent the body weight of the patient which will be acting on the scaffold once implanted inside the body. The average weight of people is 62 kg or 608 N approximately.³⁹ To account for the potential standard deviation from the average weight and to improve the factor of safety, 1000 N was applied on the scaffold.

Permeability analysis of the design using CFD

It is already established that the internal pore structure could influence the infiltration of nutrients, cell proliferation and pore size since they can influence the flow properties of the flowing medium and wall shear stress.^23,40,41 A CFD analysis was carried out on the scaffold designs using the ANSYS 2022 (Fluent) research edition. The flow field was extracted from the model using the design modeler tool available in ANSYS. The analysis estimated the permeability, represented by the letter k, of the scaffold structures. Water was used as the base fluid for the simulation with a density of 1000 kg/m³ and a viscosity of 1.45*10⁻³ Pa.s.⁴² The permeability is calculated using Darcy’s law and the equation is

k = η V L / ∆ P

(1)

Where k is the permeability, η is the dynamics viscosity of the fluid Pa.s, V is the inlet velocity in m/s, L is the length of the flow field in m and ∆P is the pressure difference in the scaffold in Pa.^26,43

Printing and sintering

The Ti powder was procured from Nano Chemazone, India and had an average particle size close to 50 µm which was confirmed using FESEM imaging (Figure 5(f)). The CS was supplied by Central Drug House, India and HA was purchased from Nano Research Lab., India. Both CS and HA have an average particle size close to 50 µm as the product which was mentioned in the product description (Mesh 275). The TI + CS and Ti + HA compositions were made using a tumbler (Figure 5(b)) machine. The powders were mixed in proportional weight, transferred into a plastic bottle and placed in the tumbler drum. The tumbler was then rotated for 24 hours at around 100 r/min to obtain a homogeneously mixed composite. The slurry is prepared using a polymer binder. 0.3 g of biocompatible Carboxy Methyl Cellulose (CMC) polymer (SD Fine Chem Limited) was added to 10 mL of water while stirring at 400 r/min. The water is heated to 80 C to aid the dissolving of CMC and the heating is stopped once the CMC is dissolved. The binder is further stirred for 10 minutes to confirm the polymer is uniformly distributed in the binder. The powder is then added to the binder at room temperature in parts and stirred using a mechanical stirrer to obtain a uniformly mixed slurry. The optimum consistency for printing, where the nozzle will extrude the slurry continuously and uniformly, was obtained when the binder to powder weight ratio is 72:28.

The optimized models were then 3D printed using the robocasting (Figure 5(a)) extrusion 3D printer and sintered in an inert atmosphere using a microwave furnace (Nanotech Microwave furnace). The pressure exerted on the extruder was 0.25 MPa and the velocity of the nozzle was 10 mm/sec. A nozzle with a diameter of 0.6 mm was selected for the printing. This is the smallest nozzle that continuously extrudes the Ti and the composite slurry. A smaller diameter nozzle (0.41 mm) produced discontinuity and distortions while printing whereas a bigger diameter (0.84 mm) reduced the pore size which is not ideal for bone scaffolds. Moreover, the increase in diameter resulted in increased self weight of the strands which led to sagging. Figure 5(c), (d) and (e) show the 50N scaffolds printed using nozzles of different diameters.

The samples were sintered at 1300°C with a heating rate of 20°C and a dwell period of 15 minutes. The sintering temperature of Ti varies between 1200°C and 1400°C. Sintering at temperatures below 1300°C produces samples whose density is less than 90% of the theoretical density while sintering at 1400°C or above cannot produce significant improvement in density compared to the 1300°C sintered samples.⁴⁴ The advantage of microwave furnace is the faster heating rate and reduced holding time with comparable densification.^45,46 Argon gas was purged twice before initiating the sintering to remove the atmospheric air inside the furnace and a flow rate of 2 L per minute was maintained till the sample was brought to room temperature.

The XRD analysis was carried out using Bruker D8 Advance which has a copper anode of 2.2 KW and ceramic X-ray tube and is operated at 35 kV voltage and 30 mA current. The step size was 0.05° and a scan speed of 0.5 s per step was used. Figure 6 represents the XRD results from Ti, CS and HA powders respectively before sintering and the selected reflection planes are marked based on International Centre for Diffraction Data (ICDD) data. The Ti powder samples have characteristic peaks at 35.3°,38.5°, 40.3°, 53.3° and 62.72° respectively which represent the α phases (1,0,0), (0,0,2), (1,0,1), (1,0,2) and (1,1,0) respectively. For the CS, the peaks at 24.77°, 26.48°, 29.28°, 34.85° and 38.31° indicates planes (2,0,0),(0,2,2), (−2,-1,1), (0,2,2) and (−1,0,3) respectively. In the case of HA, peaks are present at 26.33, 28.73, 32.39, 34.50, 40.31, 47.08, 49.84 and 53.55 indicating (0,0,2), (1,0,2), (2,1,1), (2,0,2) (3,1,1) (2,2,2), (2,1,3)and (0,0,4) planes respectively.

Result and discussion

Mechanical properties of the composite material

Initially, a mesh convergence study was carried out on Ti90CS10. Ti80CS20 and Ti70CS30 samples to optimize the mesh size and achieve reliable approximation. Mesh sizes of 1, 2, 3 and 4 were selected for the initial study. The test carried out on Ti + CS samples revealed that there is no significant difference in the final output with the variation in mesh size. The results are tabulated in Table 2 Mesh convergence study for RVE analysis. However, reducing the mesh size exponentially increased the solving time. Hence the mesh size 4 was used to solve the remaining models in the study.

Table 2.

Mesh convergence study for RVE analysis.

.Composition	Mesh size	No of Nodes	Time to solve (sec)	Resultant Young’s modulus (GPa)
Ti90CS10	1	1236651	6117	95.61
	2	218852	222	95.59
	3	90372	49	95.59
	4	40447	12	95.59
Ti80CS20	1	1443249	8216	91.99
	2	258617	312	91.99
	3	108428	51	92.00
	4	40996	12	91.99
Ti70CS30	1	1596887	12403	89.24
	2	266527	334	89.24
	3	90864	51	89.24
	4	45447	14	89.24

The addition of ceramic components reduced the mechanical properties of the composites since the ceramic particles have low Young’s modulus compared to the Ti. The Von Moises stresses and displacement developed in the samples are in Figure 7. Stress concentrations are visible at the metal-ceramic interface and the maximum stress increased with the addition of ceramic while the displacement pattern remained constant. The Young’s modulus of the composite reduced with the increase in ceramic percentage and the results are shown in Figure 8. A similar trend was observed by Topuz et al. in their experimental study with Ti and Ti + HA scaffolds developed using powder metallurgy.⁴⁷

Mechanical properties of the designed scaffolds

The mesh convergence study produced an upward trend in effective Young’s modulus with an increase in mesh size up to 2.4 while the 2.5 mesh size produced a downward trend with no significant difference indicating the mesh convergence and the details are given in Table 3 Mesh Convergence study Bulk Scaffold designs.

Table 3.

Mesh Convergence study Bulk Scaffold designs.

Design	Mesh size	No of Nodes	Time to solve (sec)	Young’s modulus (GPa)
25N	0.5	1434925	523	20.25
	1	944197	277	20.68
	1.2	648218	141	20.93
	2.4	180924	34	23.247
	2.5	174388	35	23.23
100S	0.5	2,679,603	5074	42.19
	1	1739441	1994	43.22
	1.2	1362070	1523	43.97
	2.4	344583	121	48.3
	2.5	331978	119	48.21

Hence the mesh size of 2.4 was adopted for the remaining compositions and analysis was carried out using the ABAQUS tool and the results are listed in Figure 9. With the increase in the infill pattern, Young’s modulus increased. The Young’s modulus of natural bone is between 4-30 GPa and particularly for femur bone, it is between 15-20 GPa.^48,49 Both 100 infill patterns in all compositions had the E value greater than 30 GPa which is higher than that of cortical bone and not considered for further analysis. The Ti60CS40, Ti60HA40. Ti50CS50 and Ti50HA50 samples were not considered for FEA analysis since the trend suggested they wouldn’t have the strength to be used as cortical bone scaffolds for the femur. The stepped design always outperformed the normal design counterpart for the same infill pattern. This could be due to the increased support area between the adjacent strands due to the orientation change or the reduction in porosity level as mentioned in Table 4 or both. For the Ti-CS samples, the addition of 10 % ceramic part reduced the Young’s modulus by around 4% while the Ti-HA samples fell at an average of 5%. This trend can be used to predict the Young’s modulus of other compositions. From the analysis, the 25N, 25S, 50N, 50S, 75N and 75S models had Young’s modulus between 10 GPa and 30 GPa for all compositions, except the 75S Ti model and matches the Young’s modulus of the cortical bone.

Table 4.

CFD analysis results for permeability.

Sl No	Model	Porosity (%)	Viscosity of fluid (Pa.s)	Inlet velocity (m/s)	Length of fluid Model(m)	Pressure difference (Pa)	Permeability (m²)
1	25N	65	0.00145	0.01	1.10E-02	20.465	7.79E-09
2	25S	58				23.025	6.93E-09
3	50N	47				54.83	2.91E-09
4	50S	40				209.63	7.61E-10
5	75N	37				628.83	2.54E-10
6	75S	27				1796	8.88E-11

The displacement spectrum of the applied force is shown in Figure 10 and the maximum displacement is found to be 0.0003 mm on the 25N sample which is negligible and would not impact the stability after placing in the host body.⁵⁰ The stress distribution is shown in Figure 11 and it is fairly uniformly distributed even though some stress concentrations are present at the intersection of 2 adjacent layers, The maximum stress developed is 40.86 MPa which is less than the yield stress of Ti samples developed using powder metallurgy which is around 200 MPa and the samples can efficiently transfer the load between the bones.^51,52

Permeability of the scaffold designs

Permeability is a property that depends on the geometry of the flow field such as porosity, pore size, orientation, tortuosity and interconnectivity.²⁴ Hence the test was carried on commonly for all composite materials and compositions. The permeability of a human bone lies between 1.5 × 10⁻⁹ and 5.0 × 10⁻⁸ m².^52,53 However, this value is only considered as a thumb rule since the permeability varies between cortical and cancellous bone and the location of bone as well.⁵⁴ Some studies report that the permeability could also be as low as 1 × 10⁻¹¹ for the human proximal femur bones.⁵⁰ Many factors like morphology, interconnectivity and size of pores determine the effective permeability of the scaffold.⁵⁵ The permeability of designed scaffold models obtained from the CFD analysis is given in Table 4. The length of the fluid model is 11 mm since an additional 1 mm was given at the front to avoid boundary effects.¹²

From Table 4, it is evident that only 3 designs fall within the thumb rule permeability range of bone which are 25N,25S and 50N samples. The stepped designs have lower permeability compared to the normal design scaffold. This could be due to the influence of pore size and shape on the permeability and the stepped designs have lower porosity compared to its counterpart. The pressure contours and velocity streamlines from the CFD analysis are displayed in Figure 12.

Printing and sintering

One of the suitable designs obtained from FEA and CFD analysis, 50N was printed and a sintered sample was observed using a 100X zoom digital microscope and FESEM. The 50 N sample had an average strand diameter of around 640 µm and an average pore size of around 650 µm. Previous reports suggest that this pore size is suitable for bone scaffolds to promote bone regeneration.¹² Figure 13 shows the FESEM and side view digital microscope images of the sintered samples. The images confirm the deformation of circular strands to oval shape and justify the initial assumption of strand diameter and layer height. The measurements were taken in 3 samples for strand height, strand diameter and pore size. The statistical analysis carried out on the strand height indicates that the average strand height is 500 ± 12.52 µm. The pore size calculation showed that the average pore size is 650 µm with a standard deviation of ±13.4 µm and the average strand diameter is 652 µm with a standard deviation of ±11.7 µm. The dataset has been added to the Zenodo repository.⁵⁶

The FESEM analysis confirms that the Ti was not oxidized during the sintering and the sample got adequately sintered. Figure 14(a) represents the FESEM image of the sintered Ti and the absence of gaps between particles indicates proper sintering. The visual inspection was used to confirm that the Ti is not oxidized as the oxidized samples will appear in pale or yellow colour after thermal oxidation.⁵⁷ This was confirmed by the XRD analysis and comparing the peaks with the ICDD database. However, the sintering has resulted in a phase change of the Ti samples. The Ti powder had only α phase while the sintered samples had α^,, and β phases as well along with the α phase. The peak present around 350 represents α^,, phase (1,1,0) while the peaks around 420 and 730 represent the β phase (1,1,0) and (2,1,1) respectively.⁵⁸ The thermal treatment has also resulted in a small peak shift in the α phase which is visible in Figure 14(d). Figure 14(b) and (c) shows the presence of HA and CS in the sintered samples which are highlighted by the yellow circles.

Conclusion

The RVE analysis approximately predicted the reduction in Young’s modulus with the addition of ceramic particles. This data was used to analyse the effective stiffness of the scaffold designs and found that the addition of 20% and 30% CS and HA to the Ti matrix along with the engineered design, namely 25N, 25S, 50N, 50S, 7SN and 75S, would develop structures with mechanical properties similar to a cortical bone. The CFD analysis revealed that the 50S, 75N and 75S models are not suitable for bone scaffold design as they lack the required permeability to facilitate bone regeneration, and cell and nutrient transportation. On the other hand, the 25N, 25S and 50N samples are well suited to be used as load-bearing bone scaffolds and match the required permeability and porosity. To confirm the printability of powder and sintering of the highly reactive Ti composites, 50N Ti, Ti80CS20, and Ti80HA20 samples were printed and sintered at 1300⁰C in an inert atmosphere using a microwave furnace. The FESEM analysis revealed that the samples were not oxidized during the sintering. Hence robocasting technology can be used to develop bone scaffolds and the reinforcement composition and scaffold design can be tailored to fit the requirements of the patient.

Scope for the future

The optimized sample design and composite should be 3D printed and tested for physical, mechanical and biological properties and this part should be completed before proceeding to clinical trials.

Supplemental Material

Supplemental Material - A numerical study on mechanical and permeability properties of novel design titanium based metal matrix composite bone scaffold for bone tissue engineering

Supplemental Material for A numerical study on mechanical and permeability properties of novel design titanium based metal matrix composite bone scaffold for bone tissue engineering by Umanath Puthillam and Renold Elsen Selvam in Journal of Biomaterials Applications

Footnotes

Acknowledgments

The authors would like to extend their gratitude to VIT, Vellore for providing all the facilities and infrastructure for the work.

Author contributions

Umanath Puthillam: Conceptualization, Methodology, Software, Validation, Formal analysis, Investigation, Data Curation, Writing - Original Draft. Renold Elsen Selvam: Conceptualization, Validation, Writing - Review & Editing, Supervision.

Declaration of conflicting interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

ORCID iD

Umanath Puthillam

Data availability statement

The data generated for the work has been added to the repository. Name of the repository: Zenodo. Title of the dataset: Statistical analysis. Persistent Identifier: DOI 10.5281/zenodo.14766285. Description of the file: The data and images used for statistical analysis is provided here. Data License: Creative Commons Attribution 4.0 International ().

Supplemental Material

Supplemental material for this article is available online.

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