Breakthrough thinking

Tiny sensor - huge potential

Xiao-an Zhang

A pH imbalance is serious business. Low pH levels can lead to cystic fibrosis, ischemia or cancer. But it’s been difficult to gauge these levels using current technology.

A new sensor, developed at U of T Scarborough enables a higher degree of precision when gauging pH levels in the human body.

A pH level is a measurement of the activity of protons, which are tiny charged particles that tend to attach to other molecules. “Being able to detect pH levels in a living biological system in real time is crucial to detecting and understanding conditions associated with pH imbalance,” says Xiao-an Zhang. A chemistry professor at UTSC, Zhang is an expert in developing chemical probes for biomedical imaging.

Various nuclear magnetic resonance (NMR) imaging techniques do exist, but they don’t offer an accurate-enough picture of different protonation states in real time. They are hard to measure in tissues because they move rapidly, notes Zhang, making it difficult to capture molecular location using conventional NMR time scales.

The new sensor provides a unique solution to that dilemma, by offering a slow proton exchange mechanism.

“The probe we developed can slow down proton movement and view protons at various states,” says Zhang. “It can clearly see both protonation states, so it makes for a more sensitive and accurate measurement.”

The immediate goal is to use the sensors in medical imaging. Zhang says they could have applications in other fields too, such as environmental science, biology and food studies, in areas including food production and quality control.