Close

Search

Search Menu
Photonics Media Photonics Buyers' Guide Photonics EDU Photonics Spectra BioPhotonics EuroPhotonics Industrial Photonics Photonics Showcase Photonics ProdSpec Photonics Handbook
More News
share
Email Facebook Twitter Google+ LinkedIn Comments

Pulsed Laser Irradiation Enhances Nanoplate Properties

Photonics Spectra
Feb 2018
When gold-coated silver nanoparticles are irradiated with a pulsed laser, the heat from the laser enables silver ions to escape through the gold coating, thus preserving the strong antibacterial effect of the silver.

Gold-coated silver nanoplates, when irradiated with a pulse laser, retain antibacterial properties, Kumamoto University.

When gold-coated silver nanoplates are irradiated with a pulsed laser, they change shape into a sphere and release silver ions which produces a strong antibacterial effect. Courtesy of Dr. Takuro Niidome.

Silver nanoparticles (AgNPs) are known to have antibacterial properties; but they also have a propensity to conglomerate, which reduces their antibacterial attributes. Researchers at Kumamoto University addressed the conglomeration issue by coating silver nanoparticles with gold. The gold coating eliminated conglomeration. However, it also lessened the antibacterial attributes of the silver nanoparticles, because the silver was no longer exposed. This prompted the team to investigate methods for retaining the shape of the nanoparticles as well as their antibacterial properties. 

Researchers irradiated the gold-coated silver nanoparticles (Ag@AuNPs) with a pulse laser and found that the heat from the laser caused the morphology of the nanoparticles to change from a triangular plate to a spherical shape. The team showed that Ag@AuNPs were about equal parts triangle and sphere before irradiation but became 94 percent spherical after irradiation. The team further showed that the silver-to-gold ratio of the pre-irradiation Ag@AuNPs was around 22:1, but the post-irradiation ratio was around 4.5:1. Researchers attributed this change to the generation of defects in the gold-coating, which enabled some of the silver to escape as ions. The release of the silver produced a bactericidal effect.

The irradiated Ag@AuNPs were found to be highly effective against Escherichia coli, resulting in a zero percent colony survival rate. Silver nanoparticles alone were similarly effective, but the Ag@AuNPs could be activated as needed and did not show a tendency to coalesce like the silver nanoparticles did.

“We have developed a method to activate the antibacterial properties of silver nanoparticles at will,” said professor Takuro Niidome. “Our experiments have shown that, while nonirradiated gold-coated silver nanoparticles have only minor antibacterial properties, the effects are significantly increased after pulsed laser irradiation. We hope to develop this technology further as a method of managing bacteria that have developed antibacterial resistance.”

The research was published in Nanoscale (doi: 10.1039/C7NR06513B).

Research & TechnologyeducationAsia-Pacificlaserspulsed lasersmedicalmedicinenanonanoparticlessilver nanoparticlesantibacterialgold-coated silver nanoplatesAsia-Pacific Special Section

Comments
Terms & Conditions Privacy Policy About Us Contact Us
back to top
Facebook Twitter Instagram LinkedIn YouTube RSS
©2018 Photonics Media, 100 West St., Pittsfield, MA, 01201 USA, info@photonics.com

Photonics Media, Laurin Publishing
x Subscribe to Photonics Spectra magazine - FREE!
We use cookies to improve user experience and analyze our website traffic as stated in our Privacy Policy. By using this website, you agree to the use of cookies unless you have disabled them.