Pulsed laser deposition of silver nanoparticles on prosthetic heart valve material to prevent bacterial infection

Abstract

Pyrolytic carbon (PyC) is a biomaterial widely employed as artificial heart valve but prone to bacterial infections like endocarditis. The aim of this investigation was to prevent bacterial colonisation by coating the surface of PyC with a thin film of silver nanoparticles (AgNPs) using pulsed laser deposition (PLD) technique. Thin films were deposited at 5000, 7500, 10,000, 12,500 and 15,000 ablation pulses and characterised by surface profilometer, scanning electron microscopy, energy dispersive X-ray analysis and atomic force microscopy. The antibacterial activity of AgNPs films was evaluated against gram-positive and gram-negative bacteria including methicillin resistant Staphylococcus aureus (MRSA) by the zone of inhibition method. The mean particle sizes of all AgNPs were below 30 nm and the film thickness, roughness and particle size increased with the increase in number of ablation pulses. All films of AgNPs showed significant antibacterial effect against all tested pathogens except that films prepared at 12,500 pulses alone had antibacterial activity against MRSA. The AgNPs coating had led to the betterment of haemocompatibility of PyC especially at 7500 and 10,000 ablation pulses. Film roughness as well as AgNPs’ particle size which are in nano range can be attributed to the inhibition of bacterial growth. The coating of AgNPs thin films on PyC samples using PLD technique had improved haemocompatibility properties and potential to prevent bacterial attack of the biomaterial surface.