Bilayered electrospun polymeric vascular grafts with biomimetic behavior

F. MONTINI BALLARIN; D. SUAREZ BAGNASCO; P.C. CARACCIOLO; G. RIVERO; L.J. CYMBERKNOP; G. BALAY; C. NEGREIRA; R.L. ARMENTANO; G.A. ABRAHAM

Foz de Iguazú

Congreso; 9th Latin American Congress of Artificial Organs, Biomaterials and Tissue Engineering (IX COLAOB); 2016

Sociedad Latinoamericana de Biomateriales, Órganos Artificiales e Ingeniería de Tejidos (SLABO)

Small-diameter tubular structures with potentialapplication as vascular grafts (VG) scaffolds should present compliantresponse, porous architecture, biocompatibility and bioresorbability.Electrospinning is an attractive technique to tailor VG into the desiredstructure, size and properties. The use of biomaterials composed of synthetic poly(L-lactic acid) (PLLA) andsegmented poly(ester urethane) (PHD) couldresult in biomimetic VGs because of their collagenand elastin-like mechanicalresponses, respectively. The hydrolytic degradation and mechanical response of electrospunbilayered VG made of PLLA-PHD blends were evaluated.PLLA solution (10%wt/v) in DMF/THF and PHD (25 % wt/v) in TFE and two blends, 90/10 and 50/50, wereelectrospun after setting appropriate processing conditions. Sequential electrospinningwas performed using a 5 mm diameter rotating mandrel to obtain bilayered VGs.The hydrolytic degradation was followed by GPC, FTIR, DSC, SEM and contactangle. The low initial crystallinity and highhydrophilicity of blends, along with a synergetic outcome produced by blending,led to a higher molecular weight loss. VG degraded evenly as a whole,with degradation time matching the required one for the regeneration processes.VG were subjectedto pulsatile pressure cycles in a bioreactor under physiological conditions. Thediameter variation was measured by sonomicrometry and elasticity assessment wasperformed by pressure-strain modulusand dynamic compliance. PLLA electrospungrafts showed stiff response capable of withstanding elevated pressures, while PHDgrafts presented a more elastomeric behavior. The bilayered VG stiffnessincreased with internal pressure displaying a J-shaped pressure-diameterresponse in the extended physiological range. Electrospun bioresorbable VG showeda promising biomimetic mechanical behaviorfor vascular tissueengineering. Sonomicrometrytechnique could also be applied directly in invivo experiences.