BACKGROUND & AIMS:
:Porosity, pore size and pore interconnectivity are critical factors for cellular infiltration into electrospun scaffolds. This study utilized dual electrospinning with sacrificial fiber extraction to produce scaffolds with engineered porosity and mechanical properties. Subsequently, scaffolds were covalently grafted with heparin, a known anti-coagulant with growth-factor binding properties. We hypothesized that the tissue ingrowth would correlate positively with the porosity of the scaffolds. Pellethane® (PU) was spun simultaneously with poly(ethylene oxide) (PEO, subsequently extracted). Low, medium and high porosity scaffolds and heparinized versions of each were characterized and implanted in vivo for evaluation of cellular infiltration and inflammation subcutaneously in male Wistar rats (7,14 and 28 days, n = 6). Average pore-size for low (76 ± 0.2%), medium (83 ± 0.5%) and high (90 ± 1.0%) porosity scaffolds was 4.0 ± 2.3 µm, 9.9 ± 4.2 µm and 11.1 ± 5.5 µm (p < 0.0001). Heparinization resulted in increased fiber diameter (3.6 ± 1.1 µm vs. 1.8 ± 0.8 µm, p < 0.0001) but influenced neither pore-size (p = 0.67) nor porosity (p = 0.27). Cellular infiltration for low, medium and high porosity scaffolds reached 33 ± 7%, 77 ± 20% and 98 ± 1% of scaffold width, respectively, by day 28 of implantation (p < 0001); heparinization did not affect infiltration (p = 0.89). The ultimate tensile strength (UTS) and Young's modulus (Ey ) of the constructs increased linearly with increasing PU fiber fraction (UTS: r2 = 0.97, p < 0.0001, Ey : r2 = 0.76, p < 0.0001) and heparinization resulted in decreased strength but increased stiffness compared to non-heparinized scaffolds. Increased PEO to PU fraction in the scaffold resulted in predictable losses to mechanical strength and improvements to cellular infiltration, which could make PEO to PU fraction a useful optimization parameter for small diameter vascular grafts. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1559-1572, 2017.
背景与目标:
:孔隙度,孔径和孔隙互连性是细胞渗透到电纺支架中的关键因素。这项研究利用双重电纺与牺牲纤维的提取来生产具有工程孔隙率和机械性能的支架。随后,将支架与肝素共价移植,肝素是一种具有生长因子结合特性的已知抗凝剂。我们假设组织向内生长将与支架的孔隙率成正相关。 (PU)与聚环氧乙烷(PEO,随后萃取)同时纺丝。对低,中,高孔隙率的支架和肝素化的每种支架进行表征并植入体内,以评估雄性Wistar大鼠皮下的细胞浸润和炎症(7、14和28天,n = 6)。低(76±0.2%),中(83±0.5%)和高(90±1.0%)多孔支架的平均孔径为4.0±2.3 µm,9.9±4.2 µm和11.1±5.5 µm(p <0.0001) 。肝素化导致纤维直径增加(3.6±1.1 µm与1.8±0.8 µm,p <0.0001),但既不影响孔径(p = 0.67),也不影响孔隙率(p = 0.27)。到植入第28天时,低,中和高孔隙率支架的细胞浸润分别达到支架宽度的33%±7%,77%±20%和98%±1%(p <0001);肝素化不影响浸润(p = 0.89)。结构的极限抗拉强度(UTS)和杨氏模量(Ey)随着PU纤维含量的增加而线性增加(UTS:r2 = 0.97,p <0.0001,Ey:r2 = 0.76,p <0.0001),肝素化导致强度降低但与未肝素化的支架相比增加了刚度。支架中PEO占PU分数的增加导致机械强度的可预测损失和细胞浸润的改善,这可能使PEO占PU分数成为用于小直径血管移植物的有用的优化参数。 ©2016 Wiley Periodicals,Inc.J Biomed Mater Res B部分:Appl Biomater,105B:1559-1572,2017。