Fluorescent Reporter-Based Fiber Optic Probe for Continuous Detection of Antibodies

Area of Science:

• Biotechnology
• Analytical Chemistry
• Process Engineering

Background:

• Accurate measurement of antibody and antibody fusion protein concentration is critical for biopharmaceutical process development and manufacturing.
• Current monitoring methods may not be suitable for continuous, in-line applications, limiting real-time process control.
• Molecule-specific detection is essential for reliable antibody quantification in complex cell culture media.

Purpose of the Study:

• To develop and validate a continuous, in-line monitoring platform for human immunoglobulin G (IgG) concentration.
• To assess the sensor's performance in detecting IgG in real-time within bioprocess conditions.
• To demonstrate the utility of the sensor for applications like protein A column monitoring and bioreactor titer assessment.

Main Methods:

• A fiber-optic biosensor was developed using a replaceable sensor tip.
• The sensor tip was covalently functionalized with a fluor-labeled pentamer of the Z domain of protein A.
• The platform was tested for concentration-dependent fluorescence enhancement with human IgG and specificity in Chinese hamster ovary (CHO) cell culture fluid.

Main Results:

• The biosensor demonstrated concentration-dependent fluorescence enhancement for human IgG in the range of 0.01-0.75 g/L.
• Consistent signals were observed across multiple runs at different IgG concentrations (1 and 0.1 g/L).
• The sensor maintained specificity in the presence of complex CHO cell culture fluid and could detect a 5% breakthrough from a protein A column in under 20 seconds.

Conclusions:

• The developed fiber-optic biosensor provides a robust platform for continuous, in-line, real-time IgG monitoring.
• This technology is suitable for various upstream and downstream bioprocess applications, including process control and leak detection.
• The sensor's ability to function without prior sample preparation enhances its applicability in dynamic biomanufacturing environments.