Multi-spot, label-free immunoassay on reflectionless glass.

Area of Science:

• Biosensors and Bioanalytical Chemistry
• Surface Science and Engineering
• Optical Metrology

Background:

• Biosensing platforms are crucial for diagnostics, food safety, and environmental monitoring.
• Existing platforms often face challenges with sensitivity, complexity, or cost.
• Need for robust, label-free detection methods applicable in diverse media.

Purpose of the Study:

• To develop a novel, label-free biosensing chip utilizing glass and a functional copolymer.
• To demonstrate high sensitivity and specificity for biomolecular interaction detection.
• To enable simple, cost-effective biosensing for various applications.

Main Methods:

• Fabrication of a glass biosensing chip with a silicon dioxide anti-reflective coating.
• Surface functionalization with a multi-functional dimethylacrylamide-based copolymer for antibody immobilization.
• Label-free detection of target analytes via changes in surface reflectivity using an imaging system.
• Development of a theoretical optical model for data interpretation and chip design.

Main Results:

• The biosensor successfully detected target analytes even in turbid media (e.g., human serum).
• The copolymer coating prevented non-specific adsorption, ensuring high specificity.
• Demonstrated state-of-the-art sensitivity, detecting human growth hormone down to 2.8 ng/ml.
• Achieved multiplex detection capabilities with minimal instrumental complexity.

Conclusions:

• The developed glass biosensing chip offers a sensitive, simple, and affordable solution for label-free biomolecular detection.
• The functional copolymer coating is key to enabling detection in complex biological matrices.
• This platform holds significant potential for applications in human diagnostics and monitoring.