Protein detection enabled using functionalised silk-binding peptides on a silk-coated optical fibre

Area of Science:

• Biomaterials Science
• Optical Sensing
• Surface Chemistry

Background:

• Optical fibre sensors offer sensitive detection platforms.
• Silk fibroin is a biocompatible material with versatile coating properties.
• Functionalizing optical fibres for specific analyte detection remains a challenge.

Purpose of the Study:

• To develop a novel coating procedure for optical fibre sensors using silk fibroin.
• To immobilize D-biotin onto optical fibres via a silk-binding peptide for protein detection.
• To compare two methods of SBP-biotin incorporation into silk fibroin coatings.

Main Methods:

• Optical fibres were coated with silk fibroin and SBP-biotin using dip-coating techniques (Methods A and B).
• Method A: Co-deposition of silk fibroin and SBP-biotin.
• Method B: Sequential deposition of silk fibroin followed by SBP-biotin.

Main Results:

• Surface-immobilized SBP-biotin (Method B) effectively detected streptavidin with a detection limit of 15 μg mL⁻¹.
• Silk fibroin coatings demonstrated stability to washing and water exposure.
• Lithium ions inhibited silk coating formation, requiring dialysis to reduce concentration for successful coating.

Conclusions:

• The developed silk fibroin coating procedure is suitable for creating functional optical fibre sensors.
• Surface functionalization is crucial for optimal analyte detection in silk-based optical fibre sensors.
• Optimizing silk fibroin processing, such as reducing lithium ion concentration, is essential for reliable sensor fabrication.