HOUSTON, June 29 (UPI) -- Rice University scientists say they have created the world's first nano-sized pH meter.
The researchers said their study presents biologists with the first potential means of measuring accurate pH changes inside living tissue and cells, including tumors, in real-time measurements.
"Almost every biologist I speak with comes up with one or two things they'd like to measure with this," said lead researcher Professor Naomi Halas, director of Rice's Laboratory for Nanophotonics.
Halas' team created the pH sensor using nanoshells -- optically tuned nanoparticles invented by Halas. Each nanoshell, much smaller than a living cell, contains a tiny core of non-conducting silica covered by a thin shell of metal that can be tuned to absorb or scatter specific wavelengths.
To form the pH sensor, Halas' team coated the nanoshells with pH-sensitive molecules. When illuminated and placed in solutions of varying acidity, the device provides small but easily detectable changes in the properties of the scattered light, that can be used to determine the pH of the nanodevice's local environment with high accuracy.
The study is detailed online in the journal Nano Letters.
