Substrates that are simultaneously thin, strong, optically transparent, and biocompatible have diverse applications in a range of fundamental and applied fields. While nature-derived materials offer advantages of sustainability and inherent biocompatibility compared to synthetic polymers, their brittleness and swelling, as well as surface charge and chemical functionalization non-conducive to cell growth, can hinder widespread application. In this work, we discuss the fabrication and systematic characterization of polydopamine-coated chitosan thin films. Chitosan is a widely used, partially deacetylated form of chitin, derived from crustaceans and arthropods. Polydopamine (PDA) is derived from chemistries mimicking mussel foot adhesive proteins. A facile dip-coating process of thin and flexible, uncrosslinked chitosan films in aqueous dopamine solutions leads to dramatic changes in physical and chemical properties. We show how the PDA forms time-dependent assemblies on the film surfaces, affecting surface roughness, hydrophilicity, and mechanical strength. Coating the surface for even a few seconds provides functional changes to the films. Our results shows that the optimal coating time is on the order of few hours, whereby the films are optically transparent with excellent extensibility and Young’s modulus, while further coating reduces the benefits of this surface coating. These materials are biocompatible, serving as substrates for cell adhesion and growth while maintaining good viability. Overall, these findings give insight to the effects of PDA assembly on surfaces, and illustrate how a simple, quick, and robust bioinspired coating process can prime substrates for biomedical applications such as tissue engineering, biosensing, and wound healing.

同时具有薄、坚固、光学透明和生物相容性的基材在一系列基础和应用领域具有多种应用。虽然与合成聚合物相比，天然衍生材料具有可持续性和固有的生物相容性优势，但它们的脆性和膨胀性以及不利于细胞生长的表面电荷和化学功能化会阻碍其广泛应用。在这项工作中，我们讨论了聚多巴胺涂层壳聚糖薄膜的制备和系统表征。壳聚糖是一种广泛使用的、部分去乙酰化的几丁质形式，来源于甲壳类动物和节肢动物。聚多巴胺 (PDA) 源自模拟贻贝足部粘附蛋白的化学物质。一种薄而柔韧的简便浸涂工艺，多巴胺水溶液中未交联的壳聚糖薄膜会导致物理和化学性质的巨大变化。我们展示了 PDA 如何在薄膜表面上形成依赖时间的组件，从而影响表面粗糙度、亲水性和机械强度。将表面涂覆几秒钟即可使薄膜发生功能变化。我们的结果表明，最佳涂覆时间约为几个小时，因此薄膜是光学透明的，具有出色的延展性和杨氏模量，而进一步涂覆会降低这种表面涂层的优势。这些材料具有生物相容性，可作为细胞粘附和生长的基质，同时保持良好的活力。总的来说，这些发现让我们深入了解 PDA 组装对表面的影响，并说明了如何简单、快速、