Silk patterns made by direct femtosecond laser writing

Area of Science:

• Biomaterials science
• Laser processing
• Materials science

Background:

• Silk fibroin is a biocompatible and biodegradable protein with potential applications in various fields.
• Developing precise methods for structuring silk materials is crucial for advanced applications.
• Photo-resists are essential in microfabrication for creating patterned structures.

Purpose of the Study:

• To investigate the use of femtosecond laser pulses for structuring amorphous and crystalline silk films.
• To demonstrate silk fibroin's capability as a negative-tone photo-resist.
• To explore laser-induced conformational transformations in silk.

Main Methods:

• Amorphous water-soluble silk fibroin films were exposed to tailored femtosecond laser pulses (1030 nm/230 fs).
• Water-insoluble crystalline silk films were precisely ablated from glass substrates.
• Infrared spectroscopy was used to analyze laser-induced conformational changes.

Main Results:

• Amorphous silk films patterned effectively using femtosecond lasers without photo-initiators, confirming its negative-tone photo-resist behavior.
• Precise ablation of crystalline silk films resulted in patterned silk gratings on glass.
• Laser structuring induced conformational transformations in silk, verified by spectroscopy.

Conclusions:

• Femtosecond laser processing offers a versatile and precise method for structuring silk fibroin.
• Silk fibroin can be utilized as a negative-tone photo-resist for microfabrication.
• Laser-induced modifications enable tailored conformational changes in silk for advanced material design.