Biomedical Engineering, Wayne State University, Detroit, Michigan, USA.
J Biomed Mater Res A. 2020 Oct;108(10):2023-2031. doi: 10.1002/jbm.a.36962. Epub 2020 May 14.
Growth factor (GF) delivery is a common strategy for spinal cord injury repair, however, GF degradation can impede long-term therapies. GF sequestration via heparin is known to protect bioactivity after delivery. We tested two heparin modifications, methacrylated heparin and thiolated heparin, and electrospun these with methacrylated hyaluronic acid (MeHA) to form HepMAHA and HepSHHA nanofibers. For loaded conditions, MeHA, HepMAHA, and HepSHHA fibers were incubated with soluble basic fibroblast growth factor (bFGF) or nerve growth factor (NGF) and rinsed with PBS. Control groups were hydrated in PBS. L929 fibroblast proliferation was analyzed after 24 hr of culture in either growth media or bFGF-supplemented media. Dissociated chick dorsal root ganglia neurites were measured after 3 days of cell culture in serum free media (SFM) or NGF-supplemented SFM (SFM + NGF). In growth media, fibroblast proliferation was significantly increased in loaded HepMAHA (α < .05) compared to other groups. In SFM, loaded HepMAHA had the longest average neurite length compared to all other groups. In SFM + NGF, HepMAHA and HepSHHA had increased neurite lengths compared to MeHA, regardless of loading (α < .01), suggesting active sequestration of soluble NGF. HepMAHA is a promising biomaterial for sequestering released GFs in a spinal cord injury environment and will be combined with GF filled microspheres for future studies.
生长因子 (GF) 递呈是脊髓损伤修复的常用策略，然而，GF 的降解可能会阻碍长期治疗。肝素对 GF 的隔离已知可以在递呈后保护其生物活性。我们测试了两种肝素修饰物，甲基丙烯酰肝素和巯基肝素，并将其与甲基丙烯酰化透明质酸 (MeHA) 共纺，形成 HepMAHA 和 HepSHHA 纳米纤维。对于负载条件，将 MeHA、HepMAHA 和 HepSHHA 纤维与可溶性碱性成纤维细胞生长因子 (bFGF) 或神经生长因子 (NGF) 孵育，并使用 PBS 冲洗。对照组在 PBS 中进行水合。在生长培养基或 bFGF 补充培养基中培养 24 小时后，分析 L929 成纤维细胞的增殖情况。在无血清培养基 (SFM) 或 NGF 补充 SFM (SFM+NGF) 中培养 3 天后，测量分离的鸡背根神经节突起的长度。在生长培养基中，负载 HepMAHA 的成纤维细胞增殖明显高于其他组 (α<0.05)。在 SFM 中，与其他组相比，负载 HepMAHA 的平均神经突长度最长。在 SFM+NGF 中，与 MeHA 相比，HepMAHA 和 HepSHHA 的神经突长度均增加，无论负载情况如何 (α<0.01)，这表明对可溶性 NGF 的主动隔离。HepMAHA 是一种有前途的生物材料，可用于隔离脊髓损伤环境中释放的 GFs，并将与填充 GF 的微球结合用于未来的研究。
