Raman-activated cell sorting based on dielectrophoretic single-cell trap and release.

Area of Science:

• Biotechnology
• Analytical Chemistry
• Microfluidics

Background:

• Raman-activated cell sorting (RACS) offers label-free, information-rich, and in situ single-cell analysis.
• The spontaneous Raman signal's weakness limits RACS in high-speed flow applications.
• Existing RACS methods face challenges in speed and efficiency for real-time cell identification.

Purpose of the Study:

• To develop an improved RACS microfluidic system for high-speed, label-free single-cell sorting.
• To integrate cell trapping, Raman identification, and automated separation into a single platform.
• To overcome the limitations of weak spontaneous Raman signals in flow cytometry.

Main Methods:

• A microfluidic system combining positive dielectrophoresis (pDEP) for cell trapping and release.
• A solenoid-valve-suction system for precise cell separation.
• Periodical pDEP fields to individually position cells for Raman spectroscopy.
• Sorting a mixture of carotenoid-producing yeast and Saccharomyces cerevisiae.

Main Results:

• Successfully trapped, ordered, and positioned single cells for Raman measurement.
• Achieved rapid Raman-activated cell sorting at the subsecond level.
• Enriched carotenoid-producing yeast from 9% to an average of 73%.

Conclusions:

• The developed pause-and-sort RACS microfluidic system enhances single-cell sorting speed and efficiency.
• This technology enables label-free, high-throughput cell analysis and separation.
• The system demonstrates significant potential for various biological and diagnostic applications.