Cell Surface Markers Detection: Examining Cells and Tissues at the Molecular Level

Cell Surface Markers Detection: Examining Cells and Tissues at the Molecular Level

All cells have unique proteins and molecules displayed on their surface called cell surface markers. These markers help identify cell types and functions. Detecting cell surface markers through various techniques allows researchers to classify and study cells. The discovery of new markers also helps uncover unknown cell populations and pathways. Here we explore some key techniques used for cell surface marker detection and how they advance our understanding of health and disease.

Flow Cytometry for Cell Surface Markers Detection

One of the most widely used techniques is flow cytometry. It utilizes the scattering and fluorescent properties of light to characterize cells suspended in fluid as they pass through a laser beam. Cells are first tagged with fluorescent antibodies that bind to specific surface markers. Based on the fluorescence emitted, thousands of individual cells can be analyzed at once for multiple markers. This high-throughput multi-parameter analysis enables researchers to identify rare cell populations and changes in marker expression due to experimental treatments. For example, flow cytometry revealed subtypes of immune cells and how their markers alter during infections. It is also used in cancer research for detecting tumor markers and monitoring treatment response.

Imaging Flow Cytometry for Morphology and Location Data

An advancement over conventional flow cytometry is imaging flow cytometry. In addition to fluorescence, it captures high-resolution digital images of each cell as it flows through the system. This provides information on cell morphology, internal structures, and location of surface markers on different areas of the cell membrane. Combining imaging capabilities with multiple marker detection allows exploring how marker distribution relates to cell function and development. Researchers have used it to observe tumor cell heterogeneity and track viral entry processes at a single-cell level. The spatial context from imaging flow cytometry expands our understanding beyond identifying cell types.

Mass Cytometry for Higher Dimensional Analysis

While flow/imaging flow cytometers can analyze around 12 markers simultaneously, mass cytometry raises this ceiling significantly via elemental metal isotope-tagged antibodies. Instead of fluorescence, it detects heavy metal isotopes through their mass when ionized. Coupled with time-of-flight mass spectrometry, over 40 surface markers can now be quantified per cell. cell surface enabled more comprehensive profiling and dimensional reduction techniques to discover unbiased cell types/states from thousands of cells. Mass cytometry studies revealed new immune cell subsets and uncovered pathogenic mechanisms in autoimmune diseases. The ability to interrogate cells along many parameters is transforming systems immunology research.

Microfluidic Systems for Sensitive Detection

Recent technological advances that miniaturize systems onto microfluidic chips also show promise for cell surface marker analysis. These lab-on-a-chip devices utilize microscale channels, pumps and valves to manipulate tiny volumes of fluids. Compared to traditional benchtop instruments, microfluidics offer advantages like ultra-low sample/reagent volumes, high-throughput capabilities, and portability. Some sensitive detection techniques applied in microfluidic assays include laser scanning cytometry, electrical impedance sensing, and nanowire label-free detection. Researchers have developed microfluidic devices to detect cancer biomarkers at the single-cell level with high specificity. Such sensitive chip-based assays pave the way for noninvasive liquid biopsies and point-of-care diagnostic applications.

New Markers Driven by Single-Cell Technologies

The rise of single-cell genomics, proteomics, and multi-omics techniques in recent years is revolutionizing our understanding of cellular heterogeneity. They permit comprehensive molecular profiling of individual cells without disrupting cell identity. Examples include single-cell RNA sequencing to analyze variable gene expression patterns, single-cell proteomics to identify protein markers, and single-cell multi-omics to integrate different layers of data. Leveraging these technologies, researchers continue discovering previously unknown cell types, states, and novel surface proteins that may serve as biomarkers. Some identified epithelial cancer stem cell markers showing potential for targeted therapies. Going forward, single-cell approaches will likely uncover many more protein markers critical for development, immunity and disease.

 

The analysis of cell surface markers holds tremendous value for both research and industry applications. By closely examining the protein profiles expressed on the outer membranes of cells, scientists can characterize cell lineages, disease states, and track cells both in vitro and in vivo. This molecular level of precision has enabled breakthroughs in understanding normal cell development as well as diseases. Rapid progress in discovering novel marker proteins will continue to advance fields like immunology, cancer research, and regenerative medicine. With the wealth of information provided, cell surface marker examination remains a powerful technique driving progress in biomedicine and biotechnology industry.