Counting Proteins in Single Cells with Addressable Droplet Microarrays

Area of Science:

• Biotechnology
• Molecular Biology
• Cancer Research

Background:

• Traditional cellular analysis often averages responses, masking individual cell behavior.
• Single-cell protein detection and quantification are advancing rapidly.
• Understanding protein expression variability is key in complex biological systems.

Purpose of the Study:

• To introduce a flexible single-cell analysis platform using addressable droplet microarrays.
• To enable absolute quantification of target proteins at the single-cell level.
• To investigate the expression variability of the tumor suppressor p53 in human cancer cells.

Main Methods:

• Development of a droplet microarray platform for isolating single cells in 10 nL droplets.
• Implementation of single-molecule resolution techniques for protein detection and quantification.
• Application of the platform to measure p53 protein copy numbers in cancer cells.

Main Results:

• Demonstrated a practical method for absolute protein copy number measurement with single-cell resolution.
• Quantified p53 protein expression variability in human cancer cells.
• Validated the platform's capability for analyzing diverse cell types, including primary material.

Conclusions:

• The droplet microarray platform offers a powerful tool for detailed single-cell protein analysis.
• Precise quantification of protein expression variability can be achieved for any target protein.
• This technology has broad applications in cancer research and beyond.