Quantitative microinjection using fluorescence calibration of streaming microdroplets on a superhydrophobic surface

Area of Science:

• Cell Biology
• Biophysics
• Microfluidics

Background:

• Accurate quantification of microinjected volumes is crucial for cell biology research.
• Existing methods may lack precision or reproducibility.
• Understanding dose-dependent cellular responses requires precise delivery volume measurement.

Purpose of the Study:

• To develop a simple, reproducible method for measuring the volume of liquid microinjected into cells.
• To establish a reliable calibration curve for fluorescence intensity versus volume.
• To enable accurate quantification of microinjected material in cellular studies.

Main Methods:

• A calibration curve was created by injecting fluorescent dextran droplets into oil and analyzing their fluorescence intensity and radius using Image-J software.
• Droplets were stabilized by oil medium and a superhydrophobic surface.
• Human prostate carcinoma cells (Dut-145) were microinjected with fluorescent dextran, and volumes were determined using the calibration curve.

Main Results:

• A reproducible procedure for measuring microinjection volume was successfully developed.
• A calibration curve accurately correlated droplet fluorescence intensity with volume.
• The method allowed for precise determination of the volume of solution injected into individual cells.

Conclusions:

• The developed method provides a reliable way to quantify microinjection volumes in cellular studies.
• This technique facilitates the study of relationships between microinjected material amounts and cellular effects.
• The approach is applicable to various microinjected substances, including macromolecules and drugs.