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

B. ARAOZ; N.J. LORES; D. TÄUBER; A.R. BOCCACCINI; G.A. ABRAHAM; P.C. CARACCIOLO; E.B. HERMIDA

Rio de Janeiro

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

IUMRS-ICEM

3D printing applications in tissue engineering require biomaterials with suitable mechanicaland biological properties. In this contribution, filaments were made by extrusion ofsegmented poly(ester urethane) (SPU), poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV)combined with 5 % w.w-1 Bioglass 45S5 (BG). Filaments showed an internal porousmorphology, with two microconstituents: a continuous phase and a dispersed phase. Thedispersed phase consisted of spherical particles of 800 nm in diameter. To determine thechemical composition of the phases, a novel photoinduced force microscopy (PiFM)technique was used that combines the chemical sensitivity of infrared spectroscopy with thespatial resolution of atomic force microscopy. PiFM probes the mid IR absorption in thesample by mechanical detection of the induced variation of the interaction force gradientwith a metallic tip via dynamic mode force microscopy. This allows chemicalcharacterization with spatial resolution at the nano level. ATR-FTIR spectra of PHBVshowed a characteristic band at 1280 cm-1 assigned to the ether bonds (νC-O); SPU spectra,a band around 1565 cm-1, assigned to urethane bonds (νC-N and δN-H carbonyl urethaneamide II band). Images of the spheres, acquired by PiFM, showed a strong signal at 1280cm-1, while a very low contrast was observed at 1565 cm-1. Thus, PHBV is the mainconstituent of the dispersed phase while SPU remains in the continuous phase. Theincorporation of PHBV to SPU (30 % w.w-1) led to a thermoplastic material with an elasticmodulus of (360 ± 40 MPa), twice the modulus of pure SPU; furthermore, the modulus doesnot change with the incorporation of BG. The incorporation of SPU to PHBV (30 % w.w-1) didnot modify its elastic modulus (1700 ± 200 MPa). These values are comparable to thosereported for trabecular bone. The potential bioactivity of 3D printed scaffolds was studiedthrough immersion in a simulated biological fluid (SBF).