Self-Assembly of Microstructured Protein Coatings with Programmable Functionality for Fluorescent Biosensors.

Area of Science:

• Biomaterials Science
• Molecular Engineering
• Biosensor Technology

Background:

• Proteins offer versatile, biocompatible building blocks for functional materials.
• Genetically programmable macromolecules can be engineered for specific applications.
• Self-assembling protein coatings present opportunities for advanced biosensing.

Purpose of the Study:

• To demonstrate a modular, genetically programmable protein coating platform for biosensor applications.
• To engineer protein building blocks for microstructured coatings on various substrates.
• To develop a smartphone-based fluorescent biosensor for calcium detection.

Main Methods:

• Designed and produced recombinant fusion proteins for self-assembly.
• Utilized thermally triggered liquid-liquid phase separation and coiled-coil interactions for coating formation.
• Incorporated fluorescent proteins and a genetically engineered calcium indicator protein.
• Developed a smartphone-based fluorescence imaging system for quantification.

Main Results:

• Successfully created microstructured protein coatings on glass and polymer substrates.
• Demonstrated fluorescence imaging and quantification capabilities in low-resource settings.
• Developed a calcium biosensor coating capable of measuring free calcium in the millimolar range.
• Detected abnormal physiological conditions, including mild and moderate hypercalcemia.

Conclusions:

• The modular, genetically programmable protein coating platform is effective for biosensor development.
• This approach enables the creation of accessible, low-cost fluorescent biosensors.
• The platform holds potential for detecting various biological targets beyond calcium.