Hydrazides & Biocytins

• Load by microinjection or iontophoresis
• Fixable and photostable
• Able to cross gap junctions
• Use direct detection or signal amplification

With low molecular weights (<1,000 Da) and bright fluorescent signals, these cell-impermeant polar tracers can be employed to trace neuronal projections and investigate gap junctions. They are fixable and photostable and are offered in multiple colors for multiplexing with other fluorescent probes. Biocytins can also be detected using fluorescent streptavidin conjugates for signal amplification.

Because they cross gap junctions, biocytins and hydrazides are often used to investigate neuronal communication in conjunction with labeled dextrans, which are retained within the cell.

Resources

Molecular Probes® Handbook

• Fluorescent tracers of cell morphology—Section 14.1
• Polar tracers—Section 14.3
  
• Lipophilic tracers—Section 14.4
  
• Dextran conjugates—Section 14.5
  
• Protein conjugates—Section 14.7
  
• Tracers for blood flow—Section 6.6