What technique utilizes a fluorescent dye to identify the location of target cells?

The technique that utilizes a fluorescent dye to identify the location of target cells is immunofluorescence. This method involves the use of antibodies that are specifically designed to bind to particular proteins or antigens present in cells or tissue sections. These antibodies are conjugated to fluorescent dyes, which emit light upon illumination with specific wavelengths. When the sample is exposed to a fluorescence microscope, the bound antibodies illuminate in specific areas, allowing researchers to visualize the distribution and localization of the target proteins within the cells.

In contrast, while immunohistochemistry also uses antibodies to detect proteins in tissue samples, it typically involves chromogenic detection rather than fluorescence. Western blotting primarily focuses on protein identification and quantification in isolated samples rather than cells, and flow cytometry is used to analyze cell populations based on their physical and chemical characteristics, often utilizing fluorescent markers but not specifically for visualizing cell locations in a tissue context. Thus, immunofluorescence is uniquely suited for identifying the location of target cells using fluorescent dyes.