India Ink

**Semantic type:** Indicator, Reagent, or Diagnostic Aid

**Definition:** An aqueous suspension containing carbon particulates from charcoal powder and paramagnetic oxygen (O2) sensor, that can potentially be used to assess oxygen levels using electron paramagnetic resonance (EPR) oximetry. Upon injection into tissue, the india ink has a particular EPR spectra that is very sensitive to oxygen and on the oxygen levels in tissues, and the line width of the EPR spectrum can be broadened by oxygen. Upon using EPR Oximetry, this spectrum can provide sensitive, repeated, and direct measurements of tissue oxygen and oxygenation status of tumors.

**Synonyms:** - CE India Ink - Carbon Particulate Suspension - Carlo Erba India Ink - Charcoal Suspension - Paramagnetic Charcoal Suspension