Functional nanocoatings of hollow-core microstructured optical fibers (HC-MOFs) have extended the domain of their applications to biosensing and photochemistry. However, novel modalities typically come with increased optical losses since a significant surface roughness of functional layers gives rise to additional light scattering, restricting the performance of functionalization. Here, the technique that enables a biocompatible and removable nanocoating of HC-MOFs with low surface roughness is presented. The initial functional film is formed by a layer-by-layer assembly of bovine serum albumin (BSA) and tannic acid (TA). The alkaline etching at pH 9 results in the reduction of surface roughness from 26 nm to 3 nm and decreases fiber optical losses by three times. The nanocoating can be fully removed within 7 min of the treatment. Natural biocompatibility of BSA alongside antibacterial and antifouling properties of TA makes the presented nanocoating promising for biophotonic applications.

中文翻译：

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用于空心微结构光纤的超光滑、生物相容性和可移除纳米涂层

空心微结构光纤 (HC-MOF) 的功能性纳米涂层已将其应用领域扩展到生物传感和光化学。然而，由于功能层的显着表面粗糙度会引起额外的光散射，从而限制了功能化的性能，因此新型模式通常会增加光学损耗。在这里，介绍了能够实现具有低表面粗糙度的 HC-MOF 的生物相容性和可移除纳米涂层的技术。最初的功能膜是由牛血清白蛋白 (BSA) 和单宁酸 (TA) 逐层组装而成。pH 9 的碱性蚀刻导致表面粗糙度从 26 nm 降低到 3 nm，并将光纤损耗降低三倍。纳米涂层可在处理后 7 分钟内完全去除。