What Is Multiplexed Ion Beam Imaging (MIBI)?

Multiplexed ion beam imaging (MIBI) is a technology used in biological and medical research to create highly detailed visualizations of cells and tissues. This method allows scientists to observe numerous different molecules simultaneously within a single sample. By generating comprehensive snapshots of complex biological systems, MIBI is advancing our understanding of health and disease. It offers a window into the intricate cellular landscapes that define tissues, revealing interactions and structures previously difficult to study with such clarity.

Understanding the MIBI Technique

MIBI’s “multiplexed” approach allows researchers to detect dozens of distinct proteins or cellular markers at the same time, a significant advance over traditional imaging methods limited to only a few targets. The technique uses a focused beam of primary ions, such as oxygen, directed across the surface of a prepared tissue sample in a process called rastering.

As the ion beam interacts with the tissue, it dislodges molecules from the surface to create secondary ions, which are collected and analyzed. The key to identifying specific proteins lies in the sample preparation. Researchers use antibodies designed to bind to specific molecular targets that have been tagged with stable metal isotopes. Each type of antibody is linked to a unique metal, often from the lanthanide series, that is not naturally found in biological tissues.

The liberated secondary ions enter a time-of-flight mass spectrometer (TOF-MS), which measures how long it takes each ion to travel to a detector. Because lighter ions travel faster than heavier ones, this “time of flight” allows the instrument to distinguish between the different metal isotope tags. By mapping where each metal tag was located on the sample, the system constructs a high-resolution image showing the exact position of each targeted protein.

Applications in Biological Discovery

A primary application for MIBI is in the study of cancer. Scientists use it to investigate the tumor microenvironment (TME), the complex ecosystem of cancer cells, immune cells, and blood vessels that influences tumor growth and response to treatment. By simultaneously labeling dozens of proteins, researchers can identify different types of immune cells and see how they are organized and interacting with cancer cells, providing clues as to why some tumors resist therapy.

In immunology, MIBI is used to map the intricate responses of immune cells within tissues during an infection or in cases of autoimmune disease. The technology allows for precise visualization of how different immune cell populations are distributed and communicate in their native environment. This spatial information helps in understanding how the immune system coordinates its defense or, in autoimmune disorders, mistakenly attacks the body’s own tissues.

The study of infectious diseases also benefits from MIBI. Researchers can visualize direct host-pathogen interactions at a subcellular level, observing where viruses or bacteria are located within cells and what cellular machinery they are interacting with. This provides valuable information about the mechanisms of infection and can help identify new targets for therapeutic intervention.

Beyond these fields, MIBI is applied to a range of biological questions, including research into the maternal-fetal interface, allergies, and immune tolerance. The technology’s ability to reveal the spatial organization of many different cell types and proteins at once helps researchers answer complex questions about how cells work together to form functional tissues.

Unique Capabilities of MIBI

MIBI has several capabilities that make it a powerful research tool.

• High-Plex Imaging: The technology enables the simultaneous imaging of more than 40 different markers in a single tissue section. This high degree of multiplexing provides a holistic view of cellular identity, function, and interaction within a single experiment, preventing potential artifacts that can arise from analyzing serial sections.
• Spatial Resolution: The technique provides spatial resolution at the subcellular level, meaning scientists can determine where specific proteins are located within or on the surface of cells. Preserving this tissue context is a major advantage over techniques like flow cytometry, which require the sample to be broken down into a cell suspension, thereby losing all spatial information.
• Quantitative Data: The data generated by MIBI is quantitative. The instrument measures the abundance of each metal tag, which corresponds to the amount of the target protein present. This allows for precise measurement of protein expression levels across different cells and regions of a tissue, with a dynamic range reportedly up to 1,000 times greater than conventional immunofluorescence methods.
• FFPE Compatibility: MIBI is compatible with formalin-fixed paraffin-embedded (FFPE) tissues, a standard method for preserving clinical samples. MIBI’s ability to analyze these archival tissues means that researchers can conduct retrospective studies, linking detailed molecular maps to known clinical outcomes to accelerate the discovery of new biomarkers.