Microsphere lens array embedded microfluidic chip for SERS detection with simultaneous enhancement of sensitivity and...

Area of Science:

• Spectroscopy
• Materials Science
• Microfluidics

Background:

• Surface-Enhanced Raman Spectroscopy (SERS) offers molecular fingerprinting for substance identification but faces limitations in signal collection efficiency and sample distribution.
• Traditional SERS systems require precise adjustments, hindering point-of-care applications.
• Uneven sample distribution and limited excitation power reduce signal stability and sensitivity.

Purpose of the Study:

• To develop a SERS microfluidic chip enhancing both sensitivity and stability.
• To overcome the limitations of traditional SERS for practical applications.
• To enable reliable and sensitive detection of substances in microfluidic systems.

Main Methods:

• Fabrication of a SERS microfluidic chip embedded with a barium titanate microspheres array (BTMA) via vacuum self-assembled hot-pressing.
• Utilizing the light-focusing and signal-collecting properties of high-index microspheres.
• Integrating magnetic and ultrasonic operations for uniform sample congregation on the focal plane.

Main Results:

• The BTMA effectively disperses excitation beams, creating uniform focal points and minimizing signal fluctuation.
• Achieved a limit of detection of 5 cells/mL for bacteria.
• Demonstrated excellent signal reproducibility (∼4.84% error) and position tolerance (∼5.375% error over 500 μm).

Conclusions:

• The BTMA-SERS microfluidic chip effectively addresses the trade-off between sensitivity and stability in SERS detection.
• This technology shows great promise for sensitive and stable point-of-care diagnostics.
• The integrated approach enhances SERS performance for complex biological sample analysis.