Reusable Colorimetric Biosensors on Sustainable Silk-Based Platforms

Area of Science:

• Biomaterials Science
• Biosensor Technology
• Analytical Chemistry

Background:

• Silk fibroin offers a transparent, flexible, and stable substrate for biosensor development.
• Existing biosensors often require external instrumentation, limiting their use in resource-limited settings.
• Developing point-of-care diagnostics with visual readouts is crucial for accessible healthcare.

Purpose of the Study:

• To develop a novel, instrument-free, point-of-care biosensor for glucose detection using silk fibroin.
• To utilize photoelectrochromic dithienylethene molecules within a silk film for visual glucose quantification.
• To demonstrate the biosensor's reusability and potential for detecting other analytes.

Main Methods:

• Silk fibroin films were doped with glucose oxidase, peroxidase, and dithienylethene photoelectrochromic molecules.
• Photopatterning via dithienylethene photoisomerization created dose-dependent color changes.
• Enzymatic reactions in the presence of glucose triggered color disappearance proportional to glucose concentration.

Main Results:

• The silk-based biosensor visually indicated glucose levels (hypoglycemic, normoglycemic, hyperglycemic) through color intensity changes.
• Color disappearance was proportional to glucose concentration, enabling visual assessment.
• The biosensor demonstrated reusability for up to five cycles after UV regeneration.

Conclusions:

• Silk fibroin is a suitable substrate for creating visual, reusable biosensors for resource-limited environments.
• The photopatterning approach with photoelectrochromic mediators offers a novel method for biosensor fabrication.
• This technology can be adapted for detecting other analytes by coupling with different oxidoreductases.