A first step towards practical single cell proteomics: a microfluidic antibody capture chip with TIRF detection

Area of Science:

• Biotechnology
• Cell Biology
• Analytical Chemistry

Background:

• Accurate quantification of protein levels within individual cells is crucial for understanding cellular function and disease mechanisms.
• Existing methods often lack the precision or throughput required for single-cell protein analysis.

Purpose of the Study:

• To develop and validate a novel, generic, all-optical platform for the quantitative analysis of protein copy numbers in single cells.
• To assess the precision and applicability of the platform for measuring both fluorescent proteins and endogenous proteins in cell lines.

Main Methods:

• Utilized an optical trap to isolate single cells in dedicated analysis chambers.
• Employed laser-induced microcavitation to lyse individual cells.
• Measured released proteins using total internal reflection microscopy on antibody-functionalized surfaces.

Main Results:

• Achieved a relative precision of 88% for protein measurements using the developed platform.
• Successfully quantified relative levels of the human tumor suppressor protein p53 in a breast cancer cell line using an antibody sandwich assay.
• Demonstrated the platform's capability for analyzing both transfected fluorescent proteins and endogenous unlabeled proteins.

Conclusions:

• The developed all-optical platform offers a viable and precise method for single-cell protein analysis.
• This technology has significant potential for advancing research in cell biology and disease diagnostics, particularly in cancer studies.
• The generic nature of the platform allows for adaptation to various protein targets and cell types.