Indocyanine Green (ICG) is a fascinating molecule that has transitioned from a niche diagnostic agent to a cornerstone of modern medical practice. Its unique chemical and physical properties, particularly its near-infrared fluorescence, have unlocked a wide spectrum of applications across various healthcare disciplines, from assessing liver function to guiding complex surgical procedures.

Chemically, ICG is a water-soluble cyanine dye characterized by two benzoyl indole moieties. Its molecular weight is approximately 774.96 grams per mole. The addition of sodium iodide enhances its solubility, giving the dry powder a dark brown appearance, while a diluted solution exhibits a distinct green color. The key to ICG's utility lies in its optical properties: it absorbs light in the 600–900 nm range, with maximum absorption around 875 nm, and emits fluorescence in the 750–950 nm range. Crucially, these wavelengths fall within the near-infrared (NIR) spectrum, which allows for greater tissue penetration compared to visible light. This property is fundamental to its effectiveness in both imaging and surgical guidance, enabling visualization of structures deeper within the body.

Pharmacokinetically, ICG exhibits rapid binding to plasma proteins, primarily serum albumin, after intravenous administration. It is then exclusively cleared by the liver through secretion into the biliary tree, with a short half-life typically ranging from 120 to 240 seconds. This rapid clearance and liver-specific elimination pathway make it an excellent, noninvasive tool for evaluating liver function and hepatic blood flow. Preoperative assessment of liver function using ICG parameters like plasma disappearance rate (PDR) and fractional retention at 15 min (R15) is crucial for determining the safety of hepatic resection, helping to prevent postoperative liver failure.

In surgical practice, ICG's applications are vast and continuously expanding. Its ability to visualize blood flow in real-time has made it invaluable for assessing tissue perfusion during procedures like esophagectomies and colorectal surgeries. By highlighting areas of compromised blood supply, ICG helps surgeons make informed decisions about tissue viability, thereby reducing the risk of anastomotic leaks and other complications. Furthermore, its fluorescence enables precise lymphatic mapping, crucial for sentinel lymph node biopsies in cancer staging, and facilitates intraoperative visualization of critical anatomical structures, enhancing surgical precision and safety.

The dye's use extends to ophthalmology, where ICG angiography is employed to study the choroidal vasculature, offering critical diagnostic information for conditions like age-related macular degeneration and central serous chorioretinopathy. Its high safety profile, with a high LD50, and its compatibility with advanced imaging techniques further cement its importance in clinical settings.

As a supplier of high-quality Indocyanine Green, NINGBO INNO PHARMCHEM CO.,LTD. is committed to providing the medical community with this essential dye. Our premium ICG powder ensures the reliability and accuracy required for these diverse and critical healthcare applications. The continued research and development surrounding ICG, including its use in photodynamic therapy and photoacoustic imaging, promise to unlock even more therapeutic and diagnostic potential in the future.

Keywords: Indocyanine Green | ICG Properties | Fluorescence Dye | Liver Function Tests | Surgical Guidance | NINGBO INNO PHARMCHEM CO.,LTD.