White light-activated antimicrobial surfaces: effect of nanoparticles type on activity

Area of Science:

• Materials Science
• Nanotechnology
• Photochemistry

Background:

• Hospital-acquired infections are a significant concern in healthcare settings.
• Developing effective antimicrobial surfaces is crucial for infection control.
• Traditional antimicrobial agents may face challenges with resistance and efficacy.

Purpose of the Study:

• To create novel antimicrobial polyurethane surfaces incorporating Toluidine blue O (TBO) dye and metallic nanoparticles (NPs).
• To evaluate the antimicrobial efficacy of these surfaces against Escherichia coli (E. coli).
• To investigate the mechanism behind the enhanced antimicrobial activity.

Main Methods:

• A swell-encapsulation-shrink process was used to incorporate TBO dye and Ag NPs, Au NPs, or a mixture of Ag and Au NPs into polyurethane.
• Antimicrobial activity was tested against E. coli under both white light and dark conditions.
• Mechanistic studies using furfuryl alcohol were conducted to elucidate the photochemical reactions involved.

Main Results:

• The incorporation of NPs significantly enhanced the antimicrobial activity of TBO polyurethane samples.
• Samples containing TBO/Ag NPs demonstrated potent antimicrobial activity under white light and remarkably, also in the dark.
• Bacterial populations on TBO/Ag NPs surfaces decreased below detection limits within 3 hours (white light) and 24 hours (dark).

Conclusions:

• This study presents the first antimicrobial surface combining Ag NPs and a light-activated agent (TBO) for a dual-kill mechanism.
• The enhanced photobactericidal activity is attributed to a type I photochemical reaction.
• These TBO/Ag NP-polyurethane surfaces show promise for reducing hospital-acquired infections in healthcare environments.