TMR Biocytin, a polar tracer, is utilized in researching cell-cell and cell-liposome fusions, membrane permeability, and cellular uptake during pinocytosis. Detectable with streptavidin, it serves as an effective neuronal tracer in live tissue (Ex=544 nm, Em=571 nm) [1].

TMR Biocytin is employed to assess the permeability changes in the blood-brain barrier (BBB) [2]. Guidelines (Following is our recommended protocol. This protocol provides a guideline and should be modified according to your specific needs) [2]: 1. Dilute 1 mg TMR Biocytin in 100 μL PBS (per mouse) and inject into the tail vein. 2. After 30 minutes, anesthetize and perfuse the animals. 3. Extract spinal cords and prepare deep-frozen, serial 10 μm longitudinal sections. 4. Stain nuclei with DAPI. 5. Capture images of entire sections at ×10 objective and ×10 eyepiece magnification, maintaining identical laser intensity, exposure times, and magnification across all cohorts. 6. These parameters were established using livers from both tracer-injected and non-injected mice.