The nanoprobes, dubbed "probes encapsulated by biologically localized embedding" or PEBBLEs for short, are 20 nm in diameter. That means they're small enough to fit inside a cell without interrupting its normal functions. Sensor molecules inside the PEBBLE's chemically inert matrix emit light when a selected ion such as zinc or copper binds to a specific site within the sensor.
Although scientists understand "pretty well" how such ions exit and enter a cell, they know less about how they move around once they're inside. And zinc and copper ions have important roles in functions such as muscle contraction and the nervous system.
"For the first time, we have a real shot at looking at the function of these low-abundance metal ions, which we know are so critical for cell function," said Martin Philbert, co-leader of the project.
The scientists will use statistical modelling to interpret the data from the nanoprobes, studying patterns in the motion of the ions to determine when and how individual ions trigger the cell to act in a certain way.