Hospital-acquired infections (HAIs) are among the most pressing issues in healthcare today owing to their role in rising costs, longer recovery times, and preventable patient endangerment. And among the biggest culprits and contributors to HAIs, particularly to blood and urinary tract infections, is the common catheter. Looking to reduce instances of catheter-related infections, researchers at the University of Michigan (U of M) have developed a smart catheter technology that releases a biofilm-fighting bacterial agent upon sensing the beginning of an infection.

Presented at a meeting of the American Chemical Society, the smart catheter research centers on the use of a pulsed electrochemical method for generating and modulating the release of nitric oxide (NO) to thwart biofilm formation on the surface of catheters, thereby preventing HAIs. "The NO is electrochemically generated by the reduction of nitrite ions by Cu(I) ions generated anodically at the surface of a copper electrode and subsequent cleaning of the rapidly passivated electrode surface by applying a cathodic voltage pulse," according to the researchers' abstract. "The nitrite solution and the electrodes are separated from the external test solution by the wall of a narrow bore silicone rubber tube that keeps the internal solution inside while allowing the NO gas to permeate."

Essentially, the catheter senses changes in the pH surrounding the catheter that indicate the presence of bacterial biofilm formation on the catheter. Once a threshold of infection is reached, the device releases NO, which, in turn, disrupts the formation of the bacterial film.

This 'smart' approach to combating biofilm formation is superior to current "unintelligent catheters," according to the researchers, because conventional catheters equipped with antimicrobial agents release them continuously. As a result, the catheters quickly lose their antimicrobial properties and are rendered ineffective. In contrast, the U of M's smart catheter does not release the biofilm-fighting agent until the device actually senses the start of an infection. The researchers have observed their device continue to release NO for up to seven days; however, they believe that the efficacy lifetime of the NO can be extended.