Department of Chemistry, Sapienza University of Rome, P.le A. Moro 5, 00185 Rome, Italy.
Department of Biochemical Sciences, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy.
Colloids Surf B Biointerfaces. 2017 Oct 1;158:643-649. doi: 10.1016/j.colsurfb.2017.07.047. Epub 2017 Jul 23.
Biocompatible and degradable poly(α-hydroxy acids) are one of the most widely used materials in scaffolds for tissue engineering. Nevertheless, they often need surface modification to improve interaction with cells. Aminolysis is a common method to increase the polymer hydrophilicity and to introduce surface functional groups, able to covalently link or absorb, through electrostatic interaction, bioactive molecules or macromolecules. For this purpose, multi-functional amines, such as diethylenediamine or hexamethylenediamine are used. However, common drawbacks are their toxicity and the introduction of positive charges on the surface. Thus, these kind of modified surfaces are unable to link directly proteins, such as collagens, a promising substrate for many cell types, in particular chondrocytes and osteoblasts. In this work, poly(L-lactide) (PLLA) film surface was labelled with negatively charged sulfonate groups by grafting taurine (TAU) through an aminolysis reaction. The novel modified PLLA film (PLLA-TAU) was able to interact directly with collagen. The reaction was carried out in mild conditions by using a solution of tetrabutylammonium salt of TAU in methanol. ATR-FTIR, XPS and contact angle measurements were used to verify the outcome of the reaction. After the exchange of tetrabutylamonium cation with Na, collagen was absorbed on the TAU grafted PLLA film (PLLA-TAU-COLL). In vitro biological tests with human primary chondrocytes showed that PLLA-TAU and PLLA-TAU-COLL improved cell viability and adhesion, compared to the unmodified polymer, suggesting that these modifications make PLLA substrate suitable for cartilage repair.
生物相容和可降解的聚（α-羟基酸）是组织工程支架中应用最广泛的材料之一。然而，它们通常需要表面改性以改善与细胞的相互作用。氨解是一种常见的提高聚合物亲水性和引入表面官能团的方法，这些官能团能够通过共价键合或静电相互作用，连接或吸附生物活性分子或生物大分子。为此，通常使用多官能胺，如乙二胺或己二胺。然而，常见的缺点是它们的毒性和表面正电荷的引入。因此，这些改性表面无法直接连接蛋白质，如胶原蛋白，胶原蛋白是许多细胞类型，特别是软骨细胞和成骨细胞的有前途的底物。在这项工作中，通过氨解反应将牛磺酸（TAU）接枝到聚（L-乳酸）（PLLA）薄膜表面，使薄膜表面带有负电荷的磺酸基团。新型改性 PLLA 薄膜（PLLA-TAU）能够与胶原蛋白直接相互作用。反应在温和条件下进行，使用 TAU 的四丁基铵盐在甲醇中的溶液。ATR-FTIR、XPS 和接触角测量用于验证反应的结果。在用 Na 交换四丁基铵阳离子后，胶原蛋白被吸附在接枝 TAU 的 PLLA 薄膜（PLLA-TAU-COLL）上。体外生物学测试表明，与未改性聚合物相比，PLLA-TAU 和 PLLA-TAU-COLL 提高了人原代软骨细胞的活力和黏附性，表明这些修饰使 PLLA 基质适合软骨修复。
