Silk sericin (SS) is a natural water-soluble protein with the potential to chelate metal ions via its polar groups. However, the difficulty of identifying the saturation of SS limits its application as filter films. One solution is to construct SS filter films with an indicator to reflect the degree of saturation of silk sericin. Hence, the nanocoating consisting of co-assembled SS protein and anthocyanin (C3G) nanoparticles is designed, constructed, and characterized to chelate metal ions with a saturation-visualization detection behavior. Here, metal ions Zn²⁺ and Al³⁺ are chosen as models to explore the chelating ability of SS and indicator behaviors of C3G, which could indicate the saturation degree of SS. Interestingly, after the saturation of SS in the solution and filter film situations, the visible color progressively shifts from pink to blue (Zn²⁺) or violet (Al³⁺), with the corresponding redshift of UV-Vis absorbance of C3G. Remarkable removal effectiveness of Zn²⁺ and Al³⁺, namely 93.16% and 53.97%, as well as an evident saturation-visualization detection, were identified by filter paper films with the nanocoating. Our research provides a fresh viewpoint for designing SS filter films that could effectively remove metal ions while enabling real-time viewing.

中文翻译：

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用于金属离子螯合和饱和可视化检测的丝胶-花青素纳米涂层的制备

丝胶 (SS) 是一种天然水溶性蛋白质，具有通过其极性基团螯合金属离子的潜力。然而，识别SS饱和度的困难限制了它作为滤光片的应用。一种解决方案是构建带有指示剂的 SS 滤膜，以反映丝胶的饱和度。因此，设计、构建和表征了由共组装的 SS 蛋白和花青素 (C3G) 纳米粒子组成的纳米涂层，以螯合金属离子并具有饱和可视化检测行为。这里，金属离子 Zn ²⁺和 Al ³⁺被选为模型来探索 SS 的螯合能力和 C3G 的指示行为，这可以指示 SS 的饱和程度。有趣的是，在溶液和滤膜情况下 SS 饱和后，可见颜色逐渐从粉红色变为蓝色 (Zn ²⁺ ) 或紫色 (Al ³⁺ )，C3G 的 UV-Vis 吸光度相应红移。^{纳米涂层滤纸膜对Zn 2+}和Al ³⁺的去除效果显着，分别为93.16%和53.97%，并具有明显的饱和可视化检测。我们的研究为设计能够有效去除金属离子同时实现实时观察的 SS 滤光膜提供了全新的视角。