Selection Of Fluorescent Labels For Peptides

When selecting fluorescent labels for peptides, it is important to consider the following recommendations:

• Fluorescent properties. Choose a fluorescent label with the desired excitation and emission wavelengths for your specific application. Consider factors such as brightness, photostability, and quantum yield.
• Attachment stability. Select a label that can be easily and selectively conjugated to the peptide through a stable linkage, such as an amide bond or a thioether bond. Avoid labels that may interfere with peptide structure or function.
• Compatibility with peptide properties. Consider the physicochemical properties of the peptide, such as hydrophobicity, charge, and size, when selecting a fluorescent label to ensure compatibility and stability.
• Biological compatibility. Ensure that the fluorescent label does not affect the biological activity or stability of the peptide in biological systems. Choose a label that is non-toxic and does not interfere with peptide binding or function.
• Labeling efficiency. Choose a label with high labeling efficiency to minimize the amount of label required while maximizing signal intensity for detection and imaging applications.

Pharmacology experimental studies are basically divided into two categories: in vivo studies and in vitro studies.

• For in vivo studies, fluorophores with emission wavelengths between 650-900 nm are generally selected, such as ICG (indocyanine green), Cy5.5 (Cyanine5.5), and Nile Blue. This is because the fluorescence emitted by these groups has good tissue penetration and is less affected by background interference (water, hemoglobin, and deoxyhemoglobin generally produce background interference absorption, which is around 560 nm).
• For in vitro studies, fluorophores with emission wavelengths between 400 and 600 nm are most commonly used, such as AMC (7-Amino-4-methylcoumarin), FITC (Fluorescein isothiocyanate), and TAMRA (5-Carboxytetramethyl rhodamine).