Lifetime encoding in flow cytometry for bead-based sensing of biomolecular interaction

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Biophysics

Background:

• Flow cytometry (FCM) is a powerful tool for cell analysis.
• Current FCM methods primarily rely on fluorescence intensity measurements.
• There is a need for enhanced multiplexing and sensitivity in bioassays.

Purpose of the Study:

• To demonstrate the potential of time-resolved flow cytometry (FCM) for bioanalysis and clinical diagnostics.
• To showcase the use of fluorescence lifetime (LT)-encoded beads for detecting biomolecular interactions.
• To validate a prototype lifetime flow cytometer (LT-FCM) setup.

Main Methods:

• Utilized micron-sized polymer beads with target-specific bioligands.
• Employed a prototype LT-FCM setup with photon-counting for time-resolved fluorescence decay measurements.
• Performed discrimination of bead-bound biomolecules (Streptavidin, human chorionic gonadotropin) and concentration determination (tumor necrosis factor-α).

Main Results:

• Successfully discriminated between bead-bound biomolecules in the time domain.
• Demonstrated the determination of biomolecule concentration levels using fluorescence intensity.
• Validated the applicability of LT-FCM for analyzing biomolecular interactions in suspension.

Conclusions:

• Time-resolved flow cytometry offers a promising approach for sensitive bioanalysis and diagnostics.
• LT-FCM, combined with spectral encoding, can significantly increase multiplexing capabilities.
• Future expansion of the time scale and multiplexing holds potential for high-throughput screening applications.