i3S, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua, Portugal.
INEB - Instituto de Engenharia Biomédica, Universidade do Porto, Porto, Portugal.
Sci Rep. 2017 Dec 12;7(1):17374. doi: 10.1038/s41598-017-17310-4.
N-acetyl cysteine (NAC) is an FDA-approved drug clinically applied on a broad range of pathologies. Further research has been conducted with this drug to benefit from its antimicrobial activity potential. However, NAC has a very short half-life and therefore strategies that accomplish high local concentrations would be beneficial. In this study, covalent immobilization of NAC was performed, in order to obtain long-lasting high local concentration of the drug onto a chitosan(Ch)-derived implant-related coating. For the development of NAC-functionalized Ch films, water-based carbodiimide chemistry was applied to avoid the use of toxic organic solvents. Here we report the optimization steps performed to immobilize NAC onto the surface of pre-prepared Ch coatings, to ensure full exposure of NAC. Surface characterization using ellipsometry, water contact angle measurements and X-ray photoelectron spectroscopy (XPS), demonstrated the success of NAC immobilization at 4 mg/mL. Quartz crystal microbalance with dissipation (QCM-D) demonstrated that surface immobilized NAC decreases protein adsorption to Ch coatings. Biological studies confirmed that immobilized NAC4 avoids methicillin-resistant Staphylococcus aureus adhesion to Ch coating, impairing biofilm formation, without inducing cytotoxic effects. This is particularly interesting towards further developments as a prevention coating.
N-乙酰半胱氨酸（NAC）是一种获得美国食品和药物管理局批准的药物，临床上可用于多种疾病。进一步的研究已经在该药物的基础上进行，以利用其潜在的抗菌活性。然而，NAC 的半衰期非常短，因此，完成高局部浓度的策略将是有益的。在这项研究中，通过共价固定化的方法将 NAC 固定在壳聚糖（Ch）衍生的植入物相关涂层上，以获得药物的长效高局部浓度。为了开发 NAC 功能化的 Ch 薄膜，应用了水相碳二亚胺化学，以避免使用有毒的有机溶剂。在这里，我们报告了为了确保 NAC 完全暴露而进行的将 NAC 固定到预先制备的 Ch 涂层表面的优化步骤。使用椭圆光度法、水接触角测量和 X 射线光电子能谱（XPS）进行表面表征，证明了在 4mg/mL 时 NAC 的固定化成功。石英晶体微天平（QCM-D）的测量结果表明，表面固定的 NAC 可以减少蛋白质对 Ch 涂层的吸附。生物学研究证实，固定化 NAC4 可以防止耐甲氧西林金黄色葡萄球菌黏附到 Ch 涂层上，从而破坏生物膜的形成，而不会诱导细胞毒性。这对于进一步开发作为预防涂层具有特别重要的意义。
