Non-adhesive contrast substrate for single-cell trapping and Raman spectroscopic analysis

Area of Science:

• Microfluidics and Surface Science
• Biotechnology and Bioanalysis

Background:

• Tailored surface wettability is crucial for droplet manipulation, enabling ultralow volume sample generation for applications in bioassays, tissue engineering, and material synthesis.
• Encapsulating single cells in reduced droplet volumes is key for high-throughput screening and detailed cellular analysis.

Purpose of the Study:

• To demonstrate a facile fabrication method for a non-adhesive contrast quartz substrate.
• To utilize this substrate for droplet splitting under gravitational force and single biological cell trapping for Raman spectroscopic studies.

Main Methods:

• Fabrication of a non-adhesive contrast surface by laser-assisted removal of silicone oil from a grafted quartz substrate.
• Control of hydrophilic zone dimensions via varying laser powers for precise droplet splitting.
• Demonstration of droplet splitting into pico- and sub-picolitre volumes and trapping of single polystyrene beads and biological cells.

Main Results:

• Successful creation of a non-adhesive contrast quartz substrate capable of splitting microliter droplets into pico- and sub-picolitre volumes.
• Demonstrated trapping of single polystyrene beads and recording of their Raman spectra.
• Independent recording of Raman spectra from single yeast cells and human mononuclear cells (MNCs) from daughter droplets.

Conclusions:

• The developed non-adhesive contrast surface provides a facile approach for ultralow volume droplet manipulation and single-cell isolation.
• Single-cell Raman analysis using this platform enables cell identification, type discrimination, and biochemical characterization.
• Potential applications include advanced cellular studies, clinical diagnostics, and toxicity assessments.