부산대학교 도서관

Polylactic acid (PLA) is distinguished for its high biocompatibility andelastic modulus comparable to that of human bone, which makes the polymer anideal biodegradable matrix for implants. However, the mechanical properties andradiopacity of PLA are insufficient for such application; in particular, itsradiopacity is too low to assess the position and biodegradation of implanteddevices by magnetic resonance imaging and computed tomography. Our study showsthat the level of mechanical strength, radiopacity, and biodegradationuniformity can be increased by filling a PLA matrix with magneticFe-Fe3O4 nanoparticles. Suchparticles of average size 68 nm with an α-Fe rich core and aFe3O4 shell (≈4%) were formedvia electrical iron wire explosion in an oxygen-containing atmosphere and werefilled into PLA via polymerization to obtainFe-Fe3O4@PLA compositesdiffering in Fe-Fe3O4 content. Theproperties of Fe-Fe3O4@PLA wereanalyzed on its 3D printed specimens. The analysis suggests that with aFe-Fe3O4 mass faction of up to10 wt %, the strength of the composite grows, and this prevents its fracturealong printing defects. Increasing theFe-Fe3O4 content to over 15 wt% causes the formation of nanoparticle agglomerates which act as effectivestress concentrators and the large size of which reduces their mobility when thepolymer matrix is involved in plastic flow. The presence ofFe-Fe3O4 nanoparticles greatlyincreases the radiopacity of the material and stimulates the growth of 3T3fibroblast cells. The developed material is promising for 3D printing of bonescaffolds and screws.