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Updated: May 10, 2026
A Label-free Technique for the Spatio-temporal Imaging of Single Cell Secretions
Published on: November 23, 2015
Imaging of Protein Secretion from a Single Cell Using Plasmonic Substrates
Henryk Szmacinski1, Vladimir Toshchakov, Wenji Piao
1Center for Fluorescence Spectroscopy, Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 725 W. Lombard St., Baltimore, MD, 21201, USA.
Insights
This study introduces a novel metal-enhanced fluorescence assay for detecting single-cell cytokine secretion. This method significantly boosts fluorescence, enabling precise imaging of molecular processes in immunology research.
Area of Science:
- Immunology
- Biotechnology
- Nanotechnology
Background:
- Single-cell analysis is crucial in immunology for understanding cellular responses to stimuli.
- Monitoring molecular processes, such as cytokine secretion, requires sensitive detection methods.
- Current methods for cytokine detection can be complex and require extensive biochemical procedures.
Purpose of the Study:
- To develop and demonstrate a novel imaging method for detecting single-cell cytokine secretion.
- To enhance fluorescence signals for improved sensitivity in immunoassay detection.
- To provide a simpler, more direct method for studying molecular processes controlling cell behavior.
Main Methods:
- Development of plasmonic nanostructures using silver and silica layers.
- Utilizing fluorescence microscopy for imaging molecular processes.
- Application of metal-enhanced fluorescence assay on primary mouse macrophages stimulated with lipopolysaccharide (LPS).
Main Results:
- Achieved over 200-fold fluorescence enhancement for ensemble molecules in immunoassay.
- Successfully imaged tumor necrosis alpha (TNF-α) secretion from single mouse macrophages.
- Demonstrated label-free detection of cytokine secretion without extensive biochemical procedures.
- Showcased the ability to monitor cell viability during secretion.
Conclusions:
- Plasmonic nanoparticle-enhanced fluorescence microscopy offers a powerful tool for single-cell immunology research.
- The developed assay provides sensitive and direct imaging of cytokine secretion.
- This method simplifies the study of molecular mechanisms underlying cell function and immune responses.
Abstract:
Detecting, imaging, and monitoring cell function on a single cell basis is very important in the field of immunology research where many molecules are secreted from cells in response to external stimuli including immunization. Here we introduce substrates with plasmonic nanoparticles and fluorescence microscopy as promising imaging methods for studies on molecular processes controlling cell behavior, particularly secretion of cytokines. We developed unique composition of silver and silica layers of plasmonic nanostructures which resulted in fluorescence enhancement of more than 200-fold for ensemble of molecules in the immunoassay. For the proof of concept demonstration, we used primary mouse macrophages and imaged tumor necrosis alpha (TNF-α) secretion after stimulation of the cells with lipopolysaccharide (LPS). We demonstrate that metal-enhanced fluorescence assay provides imaging capability detection of cytokine secretion from a single cell without extensive biochemical procedures as required with standard methods. In addition it is demonstrated that cell viability can be controlled during secretion.
