Scientists at the National Institute of Standards and Technology (NIST) are developing a photonic sensor to study tissue growth in the lab. The proof-of-concept sensor uses a light-based signal to measure pH, an important property in cell-growth studies. Unlike conventional sensors, the photonic sensor could be used to monitor the environment in a cell culture for weeks at a time without the need to disturb the cell-growth environment.
As cells grow, their environment becomes more acidic. If the environment becomes too acidic or too basic, the cells will die. “An increment of 0.1 pH is significant,” researcher Zeeshan Ahmed said. If researchers disturb the growing cells every time they have to measure the cell culture’s pH, they introduce another kind of uncertainty to their measurements, since they are altering the cells’ environment. For tissue engineering research, Ahmed said, a measurement system that can stay inside an incubator without needing to be removed or calibrated for weeks at a time is needed.
For years, Ahmed and his team have developed photonic sensors that use optical fibers etched with a fiber Bragg grating (FBG). Changes in temperature or pressure alter the wavelengths that can pass through the grating.