Department of Biomaterials, Faculty of Science , Iran Polymer and Petrochemical Institute , 14977-13115 , Tehran , Iran.
Department of Animal and Marine Biotechnology , National Institute of Genetic Engineering and Biotechnology , 14977-16316 Tehran , Iran.
ACS Appl Mater Interfaces. 2019 Oct 2;11(39):35525-35539. doi: 10.1021/acsami.9b07556. Epub 2019 Sep 18.
A novel poly(urethane-urea) (PUU) based on poly(glycolide--ε-caprolactone) macro-diol with tunable mechanical properties and biodegradation behavior is reported for corneal stromal tissue regeneration. Zn-Al layered double hydroxide (LDH) nanoparticles were synthesized and loaded with vitamin C (VC, VC-LDH) and dispersed in the PUU to control VC release in the cell culturing medium. To mimic the corneal stromal EC, scaffolds of the PUU and its nanocomposites with VC-LDH (PUU-LDH and PUU-VC-LDH) were fabricated via electrospinning. Average diameters of the aligned nanofibers were recorded as 325 ± 168, 343 ± 171, and 414 ± 275 nm for the PUU, PUU-LDH, and PUU-VC-LDH scaffolds, respectively. Results of hydrophilicity and mechanical properties measurements showed increased hydrophobicity and reduced tensile strength and elongation at break upon addition of nanoparticles to the PUU scaffold. VC release studies represented that intercalation of the drug in Zn-Al-LDH controlled the burst release and extended the release period from a few hours to 5 days. Viability and proliferation of stromal keratocyte cells on the scaffolds were investigated via AlamarBlue assay. After 24 h, the cells showed similar viability on the scaffolds and the control. After 1 week, the cells showed some degree of proliferation on the scaffolds, with the highest value recorded for PUU-VC-LDH. SEM images of the scaffolds after 24 h and 1 week confirmed good penetration and attachment of keratocytes on all the scaffolds and the cells oriented with the direction of nanofibers. After 1 week, the PUU-VC-LDH scaffold was fully covered by the cells. Immunocytochemistry assay (ICC) was performed to investigate secretion of vimentin protein, , and α-SMA by the cells. After 24h and 1 week, remarkably higher levels of vimentin and and lower level of α-SMA were secreted by keratocytes on PUU-VC-LDH compared to those on the PUU and PUU-LDH scaffolds and the control. Our results suggest that the aligned PUU-VC-LDH is a promising candidate for corneal stromal tissue engineering due to the presence of zinc and vitamin C.
一种基于聚（乙交酯-ε-己内酯）大分子二醇的新型聚（氨酯-脲）（PUU），具有可调节的机械性能和生物降解行为，用于角膜基质组织再生。合成了锌-铝层状双氢氧化物（LDH）纳米粒子，并负载维生素 C（VC，VC-LDH），分散在 PUU 中以控制 VC 在细胞培养介质中的释放。为了模拟角膜基质细胞外基质（EC），通过静电纺丝制备了 PUU 及其与 VC-LDH 的纳米复合材料（PUU-LDH 和 PUU-VC-LDH）的支架。记录的取向纳米纤维的平均直径分别为 325 ± 168、343 ± 171 和 414 ± 275nm 用于 PUU、PUU-LDH 和 PUU-VC-LDH 支架。亲水性和力学性能测量结果表明，向 PUU 支架中添加纳米粒子会增加疏水性并降低拉伸强度和断裂伸长率。VC 释放研究表明，药物在 Zn-Al-LDH 中的插层控制了突释，并将释放时间从几个小时延长到 5 天。通过 AlamarBlue 测定法研究了基质角膜细胞在支架上的活力和增殖。24 h 后，细胞在支架和对照上表现出相似的活力。1 周后，细胞在支架上表现出一定程度的增殖，其中 PUU-VC-LDH 记录的值最高。24 h 和 1 周后支架的 SEM 图像证实了角膜细胞在所有支架上的良好穿透和附着，并且细胞与纳米纤维的方向一致。1 周后，PUU-VC-LDH 支架完全被细胞覆盖。进行免疫细胞化学（ICC）测定以研究细胞分泌波形蛋白、α-SMA 和纤维连接蛋白。24 h 和 1 周后，与 PUU 和 PUU-LDH 支架和对照相比，角膜细胞在 PUU-VC-LDH 上分泌的波形蛋白和纤维连接蛋白水平显著更高，而 α-SMA 水平更低。我们的结果表明，由于锌和维生素 C 的存在，排列整齐的 PUU-VC-LDH 是角膜基质组织工程的有前途的候选材料。
