Study on the morphology and mechanical properties of extruded filaments composed of poly(ester urethane)/poly(3-hydroxybutyrate-co-3-hydroxyvalerate)/bioglass for 3D-printing applications in tissue engineering

ARAOZ, BEATRIZ; LORES, NAYLA; TAUBER, DANIELA; CARACCIOLO, PABLO; HERMIDA, ÉLIDA

San Pablo

Congreso; Brazil MRS Meeting & International Union of Materials Research Societies; 2021

Materials Research Society

3D printing applications in tissue engineering require biomaterials with suitable mechanical and biological properties. In this contribution, filaments were made by extrusion of poly(ester urethane) (SPU), poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) combined with 4 % w.w-1 Bioglass 45S5 (BG). SEM images of the transversal section of filaments showed an internal porous morphology, with two microconstituents: a continuous phase and a dispersed phase. The dispersed phase consisted of spherical particles of 800 nm in diameter. In oder to determine the chemical composition of the phases, a novel photoinduced force microscopy (PiFM) technique that combines the chemical sensitivity of infrared spectroscopy (FTIR) with the spatial resolution of the atomic force microscopy (AFM) was used. This technique is based on the mechanical detection of the interaction force gradient between the optically excited molecular transition dipole via mid IR quantum cascade lasers and its mirror image at the tip of an AFM; it allows spatial and chemical resolution at the nano level. ATR-FTIR spectra of PHBV showed a characteristic band at 1280 cm-1 assigned to the ether bonds; SPU spectra, a band around 1565 cm-1, assigned to amide bonds. Images of the spheres, acquired by PiFM, showed a strong signal at 1280 cm-1, while at 1565 cm-1, the spheres showed a very low contrast. These results revealed that PHBV is the main constituent of the dispersed phase while SPU remains in the continuous phase. The incorporation of PHBV to SPU (30:70) led to a thermoplastic material with an elastic modulus of (360 ± 40 MPa), that is, virtually twice the modulus of pure SPU; furthermore, the modulus does not change with the incorporation of BG. The incorporation of SPU to PHBV did not modify its elastic modulus (1700 ± 200 MPa). These values are comparable to those reported for trabecular bone. The potential bioactivity of 3D printed scaffolds was studied through immersion in a simulated biological fluid (SBF). Acknowledgments: Prof. Dr. Aldo R. Boccaccini for BG supply.