Spatial Encoding with Amplitude Modulation in Serial Flow Cytometry

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Microfluidics

Background:

• Serial flow cytometry estimates measurement uncertainty but requires complex equipment and detector synchronization.
• Replication of light sources and detectors increases complexity and cost.

Purpose of the Study:

• To introduce amplitude modulation (AM) for demultiplexing signals in serial flow cytometry.
• To design and validate an AM serial flow cytometer for improved efficiency and reduced hardware.
• To enable robust uncertainty quantification and temporal analysis in serial cytometry.

Main Methods:

• Encoding each region with a unique carrier frequency for signal demultiplexing using fast Fourier transform (FFT).
• Designing a microfluidic AM serial flow cytometer with parallel ground truth and AM detection channels.
• Evaluating metrics including event detection, dynamic range, overlapping detections, decoding accuracy, yield, and uncertainty quantification.

Main Results:

• The AM serial cytometer demonstrated high-fidelity performance, analyzing over 97% of detectable events.
• Median imprecision ranged from 0.53% to 2.1%, comparable to conventional methods.
• AM cytometry achieved accurate region decoding and uncertainty quantification, even with reduced light intensity.

Conclusions:

• AM serial flow cytometry simplifies chip design and reduces the number of photodetectors required.
• This method supports uncertainty quantification and temporal analyses with high accuracy.
• AM cytometry offers a more efficient and potentially cost-effective approach to serial flow analysis.