A new photonic biosensor can track oxygen levels in organs-on-a-chip in real-time, ensuring that these systems mimic the function of physical organs.
The photonic biosensor employs a phosphorescent gel that, like an echo, emits IR light after exposure to IR light. The amount of oxygen in the system’s environment influences the lag time between when the gel is exposed to light and when it emits the echoing flash. The shorter the lag time, the more oxygen there is. By monitoring lag times, researchers can measure the oxygen concentration in an organ-on-a-chip system down to tenths of a percent.
During the fabrication of the organ-on-a-chip, the biosensor is integrated into a 3D tissue scaffold, and oxygen concentration is controlled by controlling the flow of purging gas. The biosensor measures the local oxygen concentration in the 3D tissue scaffold by quenching palladium-benzoporphyrin with molecular oxygen. Because infrared light can pass through tissue, the researchers can use a reader that emits IR light and measures the echoing flash from the phosphorescent gel to continuously monitor oxygen levels in the tissue with lag times measured in microseconds.
The biosensor was successfully tested in 3D scaffolds with human breast epithelial cells to model healthy and cancerous tissue.