The primary goal of this study was to develop a new strategy to inactivate bacterial biofilms using the thermal stress derived from superparamagnetic iron oxide nanoparticles (SPIONs) in an alternating current (AC) magnetic field. A large number of studies have examined the inactivation of bacterial biofilms using antimicrobial agents; however, there have been no attempts to inactivate biofilms by hyperthermia using SPIONs. In this study, a SPION solution was added to Pseudomonas aeruginosa (P. aeruginosa) PA01 biofilm, and heat was generated by placing the nanoparticle-containing biofilm in an AC magnetic field. The heating temperature was dependent on the concentration of the added SPION solution. More than 4 log inactivation of the PA01 biofilm was obtained using a 60mgmL-1 SPION solution in 8min, and this resulted in a dramatic disintegration of the bacterial cell membrane in the biofilm. This inactivation was largely due to the thermal effect. Local heating of a specific area is also possible using this method, and the heating temperature can be easily adjusted by controlling the concentration of the SPION solution. Therefore, hyperthermia using magnetic nanoparticles holds promise as an effective tool for inactivating the bacterial biofilm.
Bibliographical noteFunding Information:
This work was supported by the Pioneer Research Program (No. 2010-0002229 ) and WCU (World Class University) Program through the National Research Foundation of Korea funded by the Ministry of Education, Science and Technology ( R31-10013 , and R32-2009-000-10213-0 ). This work was partly supported by the Seoul National University hospital research grants ( 21-2005-008 , 04-2006-059 , and 04-2007-084 ).
- AC magnetic field
- Pseudomonas aeruginosa PA01
- Superparamagnetic iron oxide nanoparticles