Antibacterial nitric oxide-releasing surfaces

Posted 16 August 2017

UNSW Medicinal Chemists create nitric oxide donor surfaces that could prevent bacterial infections associated with surgical implants.

Nitric oxide prevents bacteria from attaching and colonising onto implants such as hip joints, heart valves and bone grafts.

“The problem is, free nitric oxide is very unstable. It can break down within seconds,” says Dr Kitty Ho, postdoctoral researcher from the Kumar Group and first author of the report published in Chemical Communications.

The antibacterial surfaces were created by coating silicon metal with amine linkers, which then tethered the nitric oxide to the surface. The team, led by Professor Naresh Kumar and Professor Mark Willcox, polymerised the linkers onto the surface using a plasma activator, eliminating the need for potentially harmful solvents. A solvent-free system means that the nitric oxide donor surfaces could also be stored dry, preventing loss of nitric oxide – which is released immediately upon contact with aqueous solutions.

Most of the progress in the field so far have been with nitric oxide-releasing nanoparticles, which rely on the use of solvents for generation and storage. The nanoparticles then need to be injected in solution, at sites of infection.

Until now, researchers have not had much success creating nitric oxide-releasing surfaces. Some reports show limited efficiency with binding nitric oxide onto synthesized compounds. Binding nitric oxide onto an amine-coated surface was both a simple idea and a novel one.

“We had access to a plasma activator, and thought okay, let’s try this. It turned out to be a pretty simple thing to do,” says Dr Ho.