Ultrasmooth, biocompatible, and removable nanocoating for hollow-core microstructured optical fibers

Area of Science:

• Materials Science
• Optical Engineering
• Biotechnology

Background:

• Functional nanocoatings on hollow-core microstructured optical fibers (HC-MOFs) enable biosensing and photochemistry.
• High surface roughness of nanocoatings increases optical losses due to light scattering, limiting HC-MOF performance.

Purpose of the Study:

• To present a technique for creating biocompatible, removable, and low-surface-roughness nanocoatings on HC-MOFs.
• To address the challenge of optical losses associated with functionalized HC-MOFs.

Main Methods:

• Layer-by-layer assembly of bovine serum albumin (BSA) and tannic acid (TA) to form an initial functional film.
• Alkaline etching at pH 9 to reduce surface roughness and optical losses.
• Evaluation of nanocoating removability and surface properties.

Main Results:

• Surface roughness was significantly reduced from 26 nm to 3 nm after alkaline etching.
• Optical losses in the HC-MOFs were decreased by a factor of three.
• The nanocoating demonstrated full removability within 7 minutes.

Conclusions:

• The developed nanocoating technique significantly improves HC-MOF performance by reducing optical losses.
• The biocompatibility of BSA and the antibacterial/antifouling properties of TA make the coating suitable for biophotonic applications.
• The low-roughness, removable nanocoating offers a promising solution for advanced HC-MOF functionalization.