University of Pittsburgh scientists have developed a fluorescent substance that can help detect the presence of a harmful molecule in the air and body.
The researchers say that the substance glows bright green when exposed even minute amounts of ozone in the air and in biological samples such as human lung cells.
Ozone is at once a harmful pollutant and lung irritant, and a possible natural weapon that certain research suggests the human body employs against infections.
The researchers believe that their simple and fast-acting detector can function as a consumer device to measure surrounding ozone, or as a lab tool to gain insight into its effect on the human body and its debated role in the human immune system.
What distinguishes the probe from existing ozone-detection methods is the fact that it's sensitive only to ozone, say the researchers.
Current indicators can register a false-positive in response to humidity, other reactive oxygen species, and atmospheric compounds such as lead, palladium, and platinum.
"As you inhale air, you inhale ozone, and it is not known how deeply it penetrates the lung or its effect on the body," Nature magazine quoted Kazunori Koide, a chemistry professor in Pitt's School of Arts and Sciences, who is the paper's corresponding author, as saying.
"Patients with respiratory diseases who are more sensitive to ozone may be able to monitor their exposure, as should employees in industrial and laboratory jobs that include regular ozone exposure. Our method is quick, so people will know they've exceeded safe levels before they suffer the symptoms, and it's highly specific to ozone, so it will prevent having false data," Koide added.
The team's detection method consists of a small molecule-based probe added to regular distilled water. Ozone reacts with the probe through a process called ozonolysis, creating the organic compound aldehyde.
The aldehyde undergoes an additional reaction known as beta elimination to produce a substance that glows bright green-or Pittsburgh Green, as the researchers termed it-under an ultraviolet (UV) lamp or microscope.
According to the researchers, the solution began to glow within 30 minutes of coming into contact with ozone.
For the indoor experiment, the research team left paper strips coated with the solution for eight hours in an unventilated office with two photocopiers and two laser printers, devices that are known to generate ozone.
When exposed to UV light, the strips revealed concentrations of ozone captured from within the room.
To test the probe outdoors, the scientists placed the solution at four high-traffic areas in Pittsburgh for eight hours on a sunny day, but out of direct sunlight, and successfully detected ozone.
The researchers also tested the probe on human lung fluid and blood serum to determine its biomedical potential. The samples were exposed to ozone and glowed under a laser light, showing that the probe could work in biological samples.
They went further and exposed human lung cells treated with the probe to ozone-rich air for five minutes.
With a microscope, they observed the fluorescent glow expand within the cell, illustrating that ozone indeed penetrated the cell membrane.
A research article describing the probe has been published in the journal Nature Chemistry.