Is Hypochlorous acid harmful to sutures? Students in the BYU Applied Biomechanics Engineering Lab are finding out.

Post-surgery infection is a major problem that affects roughly 157,000 people each year. The medical community has largely turned to HOCl (Hypochlorous acid) to sterilize these wounds and kill bacteria. It does this job effectively, but Dr. Robert Ferguson, a plastic surgeon, started to wonder if this acid has unintended consequences. He discussed this with his nephew, Stephen Pinnock, an engineering student at BYU, who then started to study HOCl’s effects.

After surgery, doctors commonly use sutures to close wounds. They are designed to be broken down by the body and dissolve after the wound has healed. One potential consequence of treating wounds with HOCl is that it may cause sutures to break down before the wound heals completely.

To get to the bottom of this, a team of undergraduate students in the BYU Applied Biomechanics Engineering Laboratory has conducted experiments on sutures exposed to HOCl. They chose 4 commonly used suture materials and placed them in vials held in human body-like conditions for six weeks. One set of sutures were removed from the bath once a day and soaked in HOCl solution for 15 minutes. A second set of sutures were soaked twice a day, and a third set was never soaked in HOCl to serve as the control. The final set was kept out of the bath and soaked in HOCl for 15 minutes a day to simulate when sutures are exposed to air. Those conditions correspond to the typical use of HOCl in clinical practice.

To measure the impact of the HOCl, samples from each procedure were tested on a materials testing machine at 8 different times over the course of 6 weeks, the amount of time sutures need to stay strong in the body. The team developed custom grips that the suture could be wrapped around instead of using pinching or knots.

The machine works by slowly stretching the suture and measuring the force it takes for the suture to hit its breaking point.

The team has completed this work, and a paper describing the project is currently under review for publication. In the near future, this research will hopefully help the scientific community understand the effects of Hypochlorous acid and lead to improved post-surgery treatment.