Used in neuroscience and cell biology research to study neurokinin-1 (NK1) receptor distribution and function, as the substance P component binds specifically to NK1 receptors. The biotin tag allows for easy detection and visualization using streptavidin-conjugated enzymes or fluorophores in techniques like immunohistochemistry, ELISA, and flow cytometry. Enables tracking of receptor internalization and mapping of sensory nerve pathways in tissues. Also applied in affinity-based assays to isolate receptor-expressing cells or to screen drug candidates targeting substance P signaling.