Centre for the Cellular Microenvironment, University of Glasgow, Glasgow, G12 8LT, UK.
Center for Biomaterials and Tissue Engineering, Universitat Politècnica de València, Valencia, 46022, Spain.
Adv Healthc Mater. 2019 Feb;8(3):e1801469. doi: 10.1002/adhm.201801469. Epub 2019 Jan 4.
Poly-l-lactic acid (PLLA) has been used as a biodegradable polymer for many years; the key characteristics of this polymer make it a versatile and useful resource for regenerative medicine. However, it is not inherently bioactive. Thus, here, a novel process is presented to functionalize PLLA surfaces with poly(ethyl acrylate) (PEA) brushes to provide biological functionality through PEA's ability to induce spontaneous organization of the extracellular matrix component fibronectin (FN) into physiological-like nanofibrils. This process allows control of surface biofunctionality while maintaining PLLA bulk properties (i.e., degradation profile, mechanical strength). The new approach is based on surface-initiated atomic transfer radical polymerization, which achieves a molecularly thin coating of PEA on top of the underlying PLLA. Beside surface characterization via atomic force microscopy, X-ray photoelectron spectroscopy and water contact angle to measure PEA grafting, the biological activity of this surface modification is investigated. PEA brushes trigger FN organization into nanofibrils, which retain their ability to enhance adhesion and differentiation of C2C12 cells. The results demonstrate the potential of this technology to engineer controlled microenvironments to tune cell fate via biologically active surface modification of an otherwise bioinert biodegradable polymer, gaining wide use in tissue engineering applications.
聚-l-乳酸（PLLA）多年来一直被用作可生物降解聚合物；这种聚合物的关键特性使其成为再生医学中一种多功能且有用的资源。然而，它本身没有生物活性。因此，在这里，提出了一种新的方法，即用聚（丙烯酸乙酯）（PEA）刷来功能化 PLLA 表面，通过 PEA 诱导细胞外基质成分纤维连接蛋白（FN）自发组织成类似生理的纳米原纤维的能力，赋予其生物功能。该过程可以控制表面生物功能，同时保持 PLLA 的本体性质（即降解曲线、机械强度）。这种新方法基于表面引发原子转移自由基聚合，在底层 PLLA 上实现了分子级薄的 PEA 涂层。除了通过原子力显微镜、X 射线光电子能谱和水接触角来测量 PEA 接枝的表面特性外，还研究了这种表面修饰的生物活性。PEA 刷触发 FN 组织成纳米原纤维，这些原纤维保留了增强 C2C12 细胞黏附和分化的能力。结果表明，通过对原本生物惰性的可生物降解聚合物进行生物活性表面修饰来构建可控微环境以调节细胞命运的这项技术具有潜力，在组织工程应用中得到了广泛应用。
