Contactless Single Cell Extraction From Monolayer Cell Culture Using a MEMS Acoustic Droplet Ejector.

Area of Science:

• Biotechnology
• Cell Biology
• Acoustic Engineering

Background:

• Accurate and non-destructive isolation of specific cells from monolayers is crucial for various biological applications.
• Current cell extraction methods can be invasive, leading to cell damage and affecting experimental outcomes.

Purpose of the Study:

• To develop a contactless and damage-free method for extracting single or few human retinal pigment epithelial (RPE) cells using acoustic droplet ejection.
• To demonstrate precise control over the number of cells extracted and ensure their viability.

Main Methods:

• A self-focusing acoustic transducer (SFAT) based acoustic droplet ejector was designed and fabricated.
• Focused ultrasound (FUS) at 20.1 MHz with a 100 μm focal diameter was used to eject droplets containing targeted cells.
• Cell viability was assessed using fluorescence assays and re-culture experiments; gene expression was analyzed via RT-PCR.

Main Results:

• Successful extraction and collection of 1-10 human RPE cells per ejection.
• Controlled cell ejection numbers by adjusting FUS pulse width.
• Demonstrated intact cell viability and no significant gene expression changes in ejected cells compared to micropipette-collected cells.

Conclusions:

• The developed acoustic droplet ejection technology provides a contactless, damage-free method for high-resolution cell extraction.
• Precise control over cell count and maintained cell integrity are key advantages.
• This technology offers a simple yet powerful solution for cell extraction in quality control and opens possibilities for bioprinting.