Rujitanaroj Pim-On, Aid-Launais Rachida, Chew Sing Yian, Le Visage Catherine
Nanyang Technological University, School of Chemical & Biomedical Engineering, 62 Nanyang Drive, Singapore 637459, Singapore.
Biomater Sci. 2014 Jun 7;2(6):843-852. doi: 10.1039/c3bm60245a. Epub 2014 Jan 16.
Vascularization of tissue-engineered constructs is critical for proper cell and graft survival. In order to achieve this, pro-angiogenic factors, such as vascular endothelial growth factor (VEGF), are often incorporated into scaffolds by methods that either involve multiple steps or risk compromising protein bioactivity. In this study, we demonstrate a simple approach to incorporate VEGF into polysaccharide electrospun fibers by taking advantage of the interactions between VEGF and sulfated polysaccharide, fucoidan. Pullulan/dextran (P/D) electrospun fibers (diameter ∼500 nm) incorporating fucoidan were fabricated by a one-step electrospinning process. Thereafter, VEGF was loaded onto the scaffolds. By varying the content of the chemical crosslinker, trisodium trimetaphosphate (STMP), from 10 to 12 and 16 wt% (denoted as STMP10, 12 and 16 respectively), the extent of fucoidan incorporation was significantly enhanced (<2.5 mg g for STMP10 vs. 5 mg g for STMP12 and 16). In addition, increased fucoidan content resulted in prolonged retention of VEGF bioactivity (≥14 days for STMP12 and 16 vs. 3 days for STMP10 and 1 day for VEGF by bolus delivery). Subcutaneous implantation of P/D scaffolds in mice demonstrated enhanced angiogenic response towards fucoidan and VEGF loaded scaffolds at 14 days post-implantation. In addition, P/D constructs supported rapid cellular infiltration and complete biodegradation of the scaffolds was observed at 7 days post-implantation. Taken together, the results demonstrate the potential of P/D electrospun fibers endowed with fucoidan as tunable reservoirs for the effective delivery of VEGF to control vascularization of tissue-engineered constructs.
组织工程构建体的血管化对于细胞和移植物的正常存活至关重要。为了实现这一点，促血管生成因子，如血管内皮生长因子（VEGF），通常通过涉及多个步骤或有损害蛋白质生物活性风险的方法掺入支架中。在本研究中，我们展示了一种简单的方法，利用VEGF与硫酸化多糖岩藻依聚糖之间的相互作用，将VEGF掺入多糖电纺纤维中。通过一步电纺工艺制备了掺入岩藻依聚糖的支链淀粉/葡聚糖（P/D）电纺纤维（直径约500nm）。此后，将VEGF加载到支架上。通过将化学交联剂三偏磷酸钠（STMP）的含量从重量比10%、12%和16%（分别表示为STMP10、12和16）进行变化，岩藻依聚糖的掺入程度显著提高（STMP10为<2.5mg/g，而STMP12和16为5mg/g）。此外，岩藻依聚糖含量的增加导致VEGF生物活性的保留时间延长（STMP12和16为≥14天，而STMP10为3天，推注给药的VEGF为1天）。在小鼠皮下植入P/D支架，在植入后14天显示出对加载岩藻依聚糖和VEGF的支架的血管生成反应增强。此外，P/D构建体支持快速的细胞浸润，并且在植入后7天观察到支架完全生物降解。综上所述，结果表明赋予岩藻依聚糖的P/D电纺纤维作为可调谐储库有效递送VEGF以控制组织工程构建体血管化的潜力。
