a Department of Mechanical and Aerospace Engineering , Politecnico di Torino , Turin , Italy.
b Politecnico di Torino , POLITO BIOMedLAB , Turin , Italy.
J Biomater Sci Polym Ed. 2019 May;30(7):526-546. doi: 10.1080/09205063.2019.1580954. Epub 2019 Mar 28.
Poly(L-lactic) acid (PLLA) has been widely employed in tissue engineering due to its mechanical properties, biodegradability and biocompatibility. The layer-by-layer (LbL) technique was here proposed as a simple method to impart bioactivity to the surface of PLLA substrates. Aminolysis treatment was applied to introduce amino groups on the surface of PLLA solvent cast films. Then, PLLA films were coated with heparin (HE)/chitosan (CH) multilayer by the LbL technique. Each functionalization step was characterized through physico-chemical and morphological analyses. Aminolysis treatment increased film surface wettability (64.8° ± 2.4° against 74.6° ± 1.3° for untreated PLLA) due to the formation of surface amino groups, which were quantified by acid orange colorimetric assay (0.05 nmol/mm). After the deposition of 9 layers, the static contact angle varied between values close to 40° C (HE-based layer) and 60 °C (CH-based layer), showing the typical alternate trend of LbL coating. The successful HE/CH deposition was confirmed by ATR-FTIR and X-ray photoelectron spectroscopy (XPS) analyses. Particularly, XPS spectra of coated samples showed the presence of nitrogen (indicative of HE and CH deposition), and sulfur (indicative of HE deposition). The amount of deposited HE was quantified by Taylor's Blue colorimetric method: after the deposition of 19 and 20 layers the HE concentration was around 33 µg/cm. Finally, in vitro studies performed using HaCaT immortalized human skin keratinocytes, C2C12 immortalized mouse myoblasts and human fibroblasts demonstrated that HE/CH multilayer-coated PLLA is a promising substrate for soft tissue engineering, as cell response may be modulated by changing the surface chemical properties.
聚（L-乳酸）（PLLA）因其机械性能、生物降解性和生物相容性而被广泛应用于组织工程。在这里，我们提出了一种简单的方法，即层层（LbL）技术，将生物活性赋予 PLLA 基底的表面。氨基解处理被应用于 PLLA 溶剂浇铸薄膜的表面上引入氨基。然后，通过 LbL 技术将肝素（HE）/壳聚糖（CH）多层涂覆到 PLLA 薄膜上。每个功能化步骤都通过物理化学和形态分析进行了表征。氨基解处理增加了薄膜表面的润湿性（64.8°±2.4°相对于未处理 PLLA 的 74.6°±1.3°），这是由于表面氨基的形成，通过酸性橙比色测定法（0.05 nmol/mm）进行定量。在沉积 9 层后，静态接触角在接近 40°C（基于 HE 的层）和 60°C（基于 CH 的层）的值之间变化，显示出 LbL 涂层的典型交替趋势。ATR-FTIR 和 X 射线光电子能谱（XPS）分析证实了成功的 HE/CH 沉积。特别是，涂覆样品的 XPS 光谱显示了氮（表明 HE 和 CH 沉积）和硫（表明 HE 沉积）的存在。通过 Taylor 的蓝色比色法定量了沉积的 HE 量：在沉积 19 和 20 层后，HE 的浓度约为 33 µg/cm。最后，使用 HaCaT 永生化人皮肤角质形成细胞、C2C12 永生化小鼠成肌细胞和人成纤维细胞进行的体外研究表明，HE/CH 多层涂覆的 PLLA 是软组织工程有前途的基底，因为通过改变表面化学性质可以调节细胞反应。
