This is likely owing to its amphiphilic structure, with both hydrophilic and hydrophobic moieties 1, resulting in ICG binding to lipoproteins and albumin in the blood via ICG’s hydrophilic component 9, 10, with binding to the vascular endothelium secondary to affinity to the phospholipid bilayer also demonstrated 8. The emission properties vary even further when the solvent includes plasma or human albumin 5, 7, 8. At low concentrations, ICG has an absorption peak at 780nm and emission peak at 830nm as the concentration increases, ICG has a tendency to form oligomers from its previously monomeric structure, causing the absorption peak to shift to 695nm 5, 6. ICG is water-soluble and has well-established absorption and emission properties 5. The main safety consideration for use in patients is a known allergy to iodine, which has been speculated to increase the risk of a systemic reaction 3 anaphylaxis to ICG is extremely rare and has previously been reported as less that 1 in 10,000 4.

ICG has a well-established safety profile, with minimal side effects, and is approved for clinical use by the Food and Drug Administration and the European Medicines Agency. Indocyanine green (ICG) is a near infrared (NIR) fluorescent tricarbocyanine dye 1 with numerous uses in the medical field, mainly in angiography and fluorescence guided oncological tumour resection 2.

Stryker spy agent green