Measuring fluorescence-lifetime and bio-impedance sensors for cell based assays using a network analyzer integrated...

Area of Science:

• Biomedical Engineering
• Assay Development
• Sensor Technology

Background:

• Automated cell culture assays are crucial for therapeutic drug screening.
• Current systems rely on various sensors to monitor cell vitality.
• Existing reader units can be costly, complex, and large.

Purpose of the Study:

• To develop a novel reader unit for 24-well-plates capable of measuring two fluorescent sensors and electrical impedance.
• To reduce the cost, complexity, and size of existing reader units while maintaining performance.
• To combine measurement electronics and signal paths for frequency domain fluorescence and bio-impedance measurements.

Main Methods:

• Integration of measurement electronics for fluorescence and bio-impedance.
• Utilization of an integrated circuit for impedance spectroscopy.
• Development of a compact optical setup for reading sensor spots at the well bottom.
• Evaluation and compensation of measurement errors like DFT leakage and frequency-dependent signal delays.

Main Results:

• The new reader unit successfully measures two fluorescent sensors and electrical impedance.
• Performance is comparable to commercial readers, with slightly higher noise levels that can be mitigated by averaging.
• Achieved suitable accuracy for impedance measurements in the relevant biological frequency range.
• The system is significantly smaller and cheaper to manufacture.

Conclusions:

• The developed reader unit offers a cost-effective, compact, and efficient solution for cell-based assays.
• This technology can advance automated therapeutic drug screening platforms.
• The integrated approach simplifies multi-modal sensing in cell culture monitoring.