Schmitt Samantha K, Murphy William L, Gopalan Padma
Department of Material Science and Engineering, University of Wisconsin, Madison, WI 53706, USA.
J Mater Chem B. 2013 Mar 7;1(9):1349-1360. doi: 10.1039/c2tb00253a. Epub 2013 Jan 24.
We have designed a lightly crosslinked PEG based copolymer coating with compositional flexibility as well as extended stability for studying human mesenchymal stem cells (hMSCs). Copolymers contain a majority of poly(ethylene glycol) methyl ether methacrylate (PEGMEMA) as a cytophobic background with poly(ethylene glycol) methacrylate (PEGMA) for peptide coupling, and less than 10% glycidyl methacrylate (GMA) for crosslinking. Copolymer thin films were crosslinked into 30 nm thick mats by either thermal treatment or ultraviolet light and were stable for 35 days in water at 37 °C. The amount of PEGMA in the copolymer was optimized to ∼11% to minimize non-specific cell-protein interactions while maximizing the amount of total bound peptides. Following the binding of RGDSP to the mat, hMSCs were seeded. The hMSC adhesion, spreading and focal adhesion complex formation were promoted in a concentration dependent manner. Mats coupled with a non-adhesive scramble (RDGSP) maintained their cytophobicity. Competitive detachment experiments further demonstrated that cell adhesion was mediated by receptor binding to the RGDSP peptide. Cell culture experiments performed at 1 and 2 weeks show that mats can still resist cell adhesion after incubation in a serum containing medium. X-ray photoelectron spectroscopy (XPS) was effectively used to quantify the average total peptide concentration as 12.6 ± 6.14 pmol cm. A square 2.2 mm N (1s) element map shows an average value of 17.9 pmol cm of RGDSP, which correlates well with the multipoint high resolution data. The stability of the copolymer, compositional flexibility, ease of application and the ability to precisely quantify bound peptides on the mats make these materials ideal for the study of cellular processes, where stability, functionality and topography of the biointerface are relevant.
我们设计了一种基于聚乙二醇（PEG）的轻度交联共聚物涂层，它具有成分灵活性以及更长的稳定性，用于研究人间充质干细胞（hMSCs）。共聚物包含大部分聚（乙二醇）甲基醚甲基丙烯酸酯（PEGMEMA）作为疏细胞背景，聚（乙二醇）甲基丙烯酸酯（PEGMA）用于肽偶联，以及少于10%的甲基丙烯酸缩水甘油酯（GMA）用于交联。共聚物薄膜通过热处理或紫外线交联成30纳米厚的垫子，在37℃的水中可稳定35天。共聚物中PEGMA的含量优化至约11%，以尽量减少非特异性细胞-蛋白质相互作用，同时使总结合肽的量最大化。在垫子上结合RGDSP后，接种hMSCs。hMSCs的黏附、铺展和黏着斑复合物形成以浓度依赖的方式得到促进。与非黏附性乱序肽（RDGSP）偶联的垫子保持其疏细胞性。竞争性脱离实验进一步证明细胞黏附是由受体与RGDSP肽的结合介导的。在1周和2周进行的细胞培养实验表明，在含血清培养基中孵育后，垫子仍能抵抗细胞黏附。X射线光电子能谱（XPS）有效地用于量化平均总肽浓度为12.6±6.14皮摩尔/平方厘米。一个2.2毫米见方的N（1s）元素图谱显示RGDSP的平均值为17.9皮摩尔/平方厘米，这与多点高分辨率数据相关性良好。共聚物的稳定性、成分灵活性、易于应用以及精确量化垫子上结合肽的能力，使这些材料成为研究细胞过程的理想选择，在这些过程中生物界面的稳定性、功能性和拓扑结构是相关的。
