Light Responsive Silk Nanofibers: An Optochemical Platform for Environmental Applications

Area of Science:

• Materials Science
• Nanotechnology
• Biomaterials

Background:

• Silk fibroin and poly(ethylene oxide) offer biocompatibility and desirable material properties.
• Spiropyran dopants provide photocontrollable optical, mechanical, and chemical responses.
• Nanofibrous materials possess high surface-to-volume ratios for enhanced interactions.

Purpose of the Study:

• To develop novel photochromic spiropyran-doped silk fibroin-poly(ethylene oxide) nanofibers.
• To investigate the reversible optical, mechanical, and chemical properties of these composite nanofibers.
• To explore their potential as reusable nanoprobes for real-time analyte detection.

Main Methods:

• Fabrication of spiropyran-doped silk fibroin-poly(ethylene oxide) nanofibers.
• Characterization of reversible optical and mechanical property changes upon UV and visible light irradiation.
• Assessment of analyte-specific spectral changes upon interaction with acidic vapors and heavy metal ions.

Main Results:

• Demonstrated reversible variation in absorption, emission signals, and Young's modulus.
• Confirmed spiropyran's photoconversion to merocyanine as the mechanism for property changes.
• Achieved rapid (30-60 s) optical and visual detection of analytes with high sensitivity and specificity.
• Showcased regeneration of the sensing platform for over 20 (acid) and 3 (ion) cycles.

Conclusions:

• The developed silk composite nanofibers exhibit excellent photocontrolled properties.
• The straightforward preparation method allows for tunable compliance and reusable nanoprobes.
• These materials are suitable for real-time optical detection in biomedical, environmental, and industrial applications.