Researchers have come up with cool plasma packs that may provide new ways to safely fight tenacious biofilm infections in patients, and thereby revolutionize many facets of medicine.
Chunqi Jiang, a research assistant professor in the Ming Hsieh Department of Electrical Engineering-Electrophysics, and Parish Sedghizadeh, assistant professor of clinical dentistry and Director of the USC Center for Biofilms from the University of Southern California School of Dentistry and Viterbi School of Engineering, describe biofilms as complex colonies of bacteria suspended in a slimy matrix that grants them added protection from conventional antibiotics.
Reporting their study in the journal Plasma Processes and Polymers, the researchers point out that biofilms are responsible for many hard-to-fight infections in the mouth and elsewhere.
They have revealed that during the study, biofilms cultivated in the root canal of extracted human teeth were easily destroyed with the plasma dental probe, as evidenced by scanning electron microscope images of near-pristine tooth surfaces after plasma treatment.
Jiang says that plasma consists of electrons, ions and neutral species and is the most common form found in space, stars and lightning.
However, while many natural plasmas are hot, the probe developed for the study is a non-thermal, room temperature plasma that's safe to touch.
Before treatment, the research team placed temperature sensors on the extracted teeth, and found that the temperature of the tooth increased for just five degrees after 10 minutes of exposure to the plasma.
Jiang says that the cooler nature of the experimental plasma comes from its pulsed power supply.
She adds that the pulsed power supply, instead of employing a steady stream of energy to the probe, sends 100-nanosecond pulses of several kilovolts to the probe once every millisecond, with an average power less than 2 Watts.
"Atomic oxygen (a single atom of oxygen, instead of the more common O2 molecule) appears to be the antibacterial agent," according to plasma emission spectroscopy obtained during the experiments, she said.
Considering the initial findings that non-thermal plasma seems safe for surrounding tissues, Sedghizadeh hopes that dentists and other doctors will find it very useful in future.
"Plasma is the future. It's been used before for other sterilization purposes but not for clinical medical applications, and we hope to be the first to apply it in a clinical setting," Sedghizadeh said.
"We believe we're the first team to apply plasma for biofilm disinfection in root canals. This collaboration is very unique. We're attacking frontier problems, and we're happy to be broadening our fields," Jiang added.
A research article on this work has been published in the journal Plasma Processes and Polymers.