3D printing of PLA/PCL-Allograft Bone powder scaffold for bone tissue engineering application

3D printing of PLA/PCL-Allograft Bone powder scaffold for bone tissue engineering application
Mahsa Delyanee,^1,* Sara Tabatabaee,² Reza Samanipour,³ Amirhossein Tavakoli,⁴
1. Biomedical Engineering Department, Amirkabir University of Technology, Tehran, Iran
2. Bio-Computing Department, Interdisciplinary Sciences and Technologies Faculty, Tarbiat Modares University, Tehran, Iran
3. Research and Development Department, Iranian Tissue Product Company, Tehran, Iran
4. Iranian Tissue Bank & Research Center, Gene, Cell, and Tissue Research Institute, Tehran University of Medical Sciences, Tehran, Iran
Introduction: Currently, over two million bone transplant surgeries are conducted globally on an annual basis. Addressing bone defects of significant size caused by tumors or trauma remains an unresolved requirement in the clinical field. Presently employed therapies involving xenografts, autografts, or allografts are burdened by several notable constraints, such as restricted availability, complications at the donor site, and the potential for disease transmission. Additionally, there exists a possibility of rejection by the body's immune system towards foreign materials. The process of surgically reconstructing bone tissue defects is both time-intensive and technically challenging. The desired outcome is not consistently attained, leading to patients experiencing lingering pain, lack of bone union, or infections resistant to treatment. Subsequently, a choice might be taken to proceed with a secondary amputation. Spatial printing, also known as 3D printing, involves creating tangible items using a computer-generated model. The utilization of 3D printing for bone grafts is increasingly significant and growing in popularity. The selection of the approach directly affects patient readiness for surgery, the likelihood of transplant rejection, and numerous other potential complications.
Methods: Allograft bone powders (BP) were introduced into acetone and subjected to 2 hours of sonication to yield a suspension containing 10 wt%. The suspension was combined with a PLAPCL solution in DCM, and then extensively mixed and ultrasonically dispersed for a duration of 2 hours. Ultimately, the PLAPCL-BP composite block was acquired once the solvent evaporated at ambient temperature. Fused deposition modeling (FDM) printers necessitate an original print material in the form of filament with a specific diameter. Therefore, converting the composite block into filament is crucial. The composite block that was prepared underwent crushing using a mechanical crusher to yield composite powders. Subsequently, these powders were melted and extruded to generate filaments suitable for 3D printing. The object model was created using 3D modeling software (Solidworks, Dassault Systemes, France) and saved in the widely used STL format for 3D printing. Subsequently, the slicing software (Simplify 3D, America) was employed to determine the printing path. The morphology of all specimens was assessed using a scanning electron microscope (SEM; SU3500, Japan). Before observation, a gold sputter-coating was applied to all specimens. Subsequently, the SEM images were processed and the samples' pore sizes were measured using Image-J software.
Results: The PLA/PCL-BP scaffold could be efficiently printed using FDM technology. Furthermore, the printed scaffolds didn't need additional post-printing procedures (apart from rinsing and sterilization) before implantation, and they displayed appropriate mechanical and physical characteristics that allowed for additional handling. The micromorphology of the FDM-printed PLA/PCL-BP scaffold was examined using SEM. The figure revealed that all porous scaffolds exhibited a consistent macro structure, where filaments within the same layer ran in parallel, and adjoining layers intersected at a 90° angle. This printing approach resulted in the creation of a well-connected macroporous structure. The surface of the composite scaffold displayed noticeable exposed BP particles. Analysis through image processing with Image-J software indicated that the scaffold encompassed pores within the size range of 500-700 µm.
Conclusion: This study accomplished the successful fabrication of PLA/PCL-BP composite scaffolds featuring a substantial BP content through FDM 3D printing technology. This method, known for its affordability, convenience, and stability, facilitates the swift introduction of personalized bone repair biomaterials into clinical use.
Keywords: 3D printing; Bone grafts; Polylactic acid; Poly caprolactone; Scaffold.