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Fabrication and Characterization of Polylactic Acid-Mg Composites by 3d Printing Method for Biomedical Applications

Bakhshi, Rasoul | 2023

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 56459 (07)
  4. University: Sharif University of Technology
  5. Department: Materials Science and Engineering
  6. Advisor(s): Alizadeh, Reza; Abachi, Parvin
  7. Abstract:
  8. Polylactic acid (PLA) is considered as a great option to be employed as 3D porous scaffold in tissue engineering applications owing to its excellent biocompatibility and processability. However, relatively weak mechanical properties, low degradation rate and inappropriate biodegradability limit its extensive usage. In order to overcome the mentioned challenges, micrometric magnesium (Mg) particles were incorporated into the PLA matrix by the fused deposition modeling (FDM) technique. The effects of various Mg contents (i.e., 2, 4, 6, 8 and 10 wt%) on the mechanical, thermal, structural, wettability, rheological, biodegradability characteristics and cellular behavior of the 3D porous PLA-Mg composite scaffolds were evaluated. The results revealed that adding up to 8%wt magnesium improved the printability of the samples, whereas higher percentages caused voids and reduced printability. This led to an improvement in mechanical properties of samples with up to 8% Mg and accordingly, tensile strength increased from 30 MPa (pure PLA sample) to 42 MPa for the PLA-Mg composite, while compressive strength increased from 15.7 MPa )pure PLA sample( to 20.5 MPa for the composite. In addition, the elastic modulus showed an improvement of 23.5% and 42% in both tensile and compressive modes. Biological results showed that adding up to 6% magnesium increased cell growth and compatibility on the scaffold. However, in the sample with 8% magnesium, cell adhesion and compatibility decreased, and the environment became toxic for the cells. Furthermore, biodegradability tests showed that, after four weeks, PLA-6%Mg sample was degraded six times more than the pure sample, the amount of degradation increased from 0.2% for the pure sample to 1.2% for the magnesium sample. The overall results of this study greatly suggest that the 3D-printed PLA-Mg composite scaffold is a promising candidate for tissue engineering applications
  9. Keywords:
  10. Mechanical Properties ; Three Dimentional Printing ; Polylactic Acid ; Fused Deposition Modeling (FDM) ; Polylactic Acid-Magnesium Composites ; Biomedical Model ; Biodegradable Scaffold

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