Ramu M, Ananthasubramanian M, Kumaresan T, Gandhinathan R, and Jothi S
Bio-medical materials and engineering [Biomed Mater Eng] 2018; Vol. 29 (6), pp. 739-755.
Bone and Bones, Cell Line, Cell Proliferation, Compressive Strength, Computer Graphics, Computer Simulation, Finite Element Analysis, Humans, Lasers, Materials Testing, Nylons chemistry, Polyesters, Porosity, Stress, Mechanical, Biocompatible Materials chemistry, Durapatite chemistry, Femur physiopathology, Tissue Engineering methods, and Tissue Scaffolds
Numerous biomaterials are used to fabricate bone scaffolds to repair the bones subjected to trauma. The scaffolds are fabricated with interconnected pores with 40-70% porosity to facilitate the entry of the cells that ensures rapid bone formation. In addition, the interconnected pores also serve as a channel for the exchange of nutrients and waste materials. Rapid prototyping techniques use the CAD model of the scaffold to be fabricated which facilitates fabrication of components with complex architecture easily. This research deals with the design, fabrication and analysis of porous scaffold models with different configurations. Apart from the conventional pore geometry like cubical, spherical shaped pores, their shifted arrangements were also considered for this study. The minimum pore size used for the study is 400 μm and the porosity ranges from 40-70%. Based on the results of finite element analysis, the best scaffold configuration is identified and was fabricated with different build orientation using Selective Laser Sintering (SLS) process with different mix of Polyamide and Hydroxyapatite. The fabricated test specimens were evaluated based on mechanical tests for its strength and in vitro studies with human osteosarcoma cell line for cell growth studies. The mechanical tests witnesses good physical properties than the earlier reported research. The suitability of the porous scaffolds for bone repair is also ensured using finite element analysis of a human femur bone under various physical activities.
The ability to use biological substitutes to repair or replace damaged tissues lead to the development of Tissue Engineering (TE), a field that is growing in scope and importance within biomedical engineering. Anchorage dependent cell types often rely on the use of temporary three-dimensional scaffolds to guide cell proliferation. Computer-controlled fabrication techniques such as Rapid Prototyping (RP) processes have been recognised to have an edge over conventional manual-based scaffold fabrication techniques due to their ability to create structures with complex macro- and micro-architectures. Despite the immense capabilities of RP fabrication for scaffold production, commercial available RP modelling materials are not biocompatible and are not suitable for direct use in the fabrication of scaffolds. Work is carried out with several biocompatible polymers such as Polyetheretherketone (PEEK), Poly(vinyl alcohol) (PVA), Polycaprolactone (PCL) and Poly(L-lactic acid) (PLLA) and a bioceramic namely, Hydroxyapatite (HA). The parameters of the selective laser sintering (SLS) process are optimised to cater to the processing of these materials. SLS-fabricated scaffold specimens are examined using a Scanning Electron Microscope (SEM). Results observed from the micrographs indicate the viability of them being used for building TE scaffolds and ascertain the capabilities of the SLS process for creating highly porous scaffolds for Tissue Engineering applications.