Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New technique for rapidly killing bacteria using tiny gold disks and light

18.03.2016

Research team from University of Houston find that the light-activated gold nanoparticles destroy potentially deadly bacterial cells in seconds

Researchers have developed a new technique for killing bacteria in seconds using highly porous gold nanodisks and light, according to a study published today in Optical Materials Express, a journal published by The Optical Society. The method could one day help hospitals treat some common infections without using antibiotics, which could help reduce the risk of spreading antibiotics resistance.


This is an artist's interpretation of how bacteria cells on a nanoporous gold disk array are killed after exposure to near-infrared light.

Credit: Greggy M. Santos and Wei-Chuan Shih

"We showed that all of the bacteria were killed pretty quickly . . . within 5 to 25 seconds. That's a very fast process," said corresponding author Wei-Chuan Shih, a professor in the electrical and computer engineering department, University of Houston, Texas.

Scientists create gold nanoparticles in the lab by dissolving gold, reducing the metal into smaller and smaller disconnected pieces until the size must be measured in nanometers. One nanometer equals a billionth of a meter. A human hair is between 50,000 to 100,000 nanometers in diameter. Once miniaturized, the particles can be crafted into various shapes including rods, triangles or disks.

Previous research shows that gold nanoparticles absorb light strongly, converting the photons quickly into heat and reaching temperatures hot enough to destroy various types of nearby cells - including cancer and bacterial cells.

In 2013, Shih and his colleagues from the University of Houston created a new type of gold disk-like nanoparticle that measures to a few hundred nanometers in diameter. The disks are riddled with pores, lending the particles a sponge-like look that helps increase their heating efficiency while maintaining their stability, said Shih.

In the new work, the researchers set out to test the antimicrobial properties of their new nanoparticles when activated by light. They grew bacteria in the lab including E. coli and two types of heat-resistant bacteria that thrive in even the most scorching environments such as the hot springs of Yellowstone National Park.

Then, they placed the bacteria cells on surface of a single-layer coating of the tiny disks and shone near infrared light from a laser on them. Afterward, they used cell viability tests and SEM imaging to see what percentage of cells survived the procedure.

Using a thermal imaging camera, the research team showed that the surface temperature of the particles reached temperatures up to 180 degrees Celsius nearly instantaneously, "delivering thermal shocks" into the surrounding array. As a result, all of the bacterial cells were killed within 25 seconds, the researchers report.

E. coli proved most vulnerable to the treatment; all of its cells were dead after only five seconds of laser exposure. The other two types of bacteria required the full 25 seconds, but that's still much quicker than traditional sterilization methods such as boiling water or using dry-heat ovens, which can take minutes to an hour to work, said Shih. And it's "considerably shorter" than what other nanoparticle arrays have demonstrated in recent studies, the researchers write. The time needed to achieve similar levels of cell death in those studies ranges from 1 to 20 minutes.

In control trials, the researchers found that neither the gold disks nor light from the laser alone killed nearly as many cells.

The technique has important potential biomedical applications, said Shih. Currently, the researchers are investigating using the particles as a simple coating for catheters to help reduce the number of urinary tract infections in hospitals.

"Any sort of light activated procedure would be much easier to implement at the bedside of a patient," instead of removing and potentially replacing the catheter every time it needs to be cleaned, he said.

Another potential application they're exploring is integrating the nanoparticles with filter membranes in small water filters, he said, to help improve water quality.

###

Paper: Greggy M. Santos, Felipe Ibañez de Santi Ferrara, Fusheng Zhao, Debora F. Rodrigues, and Wei-Chuan Shih, "Photothermal inactivation of heat-resistant bacteria on nanoporous gold disk arrays," Opt. Mater. Express 6, 1217-1229 (2016).

About Optical Materials Express

Optical Materials Express (OMEx) is an open-access journal focusing on the synthesis, processing and characterization of materials for applications in optics and photonics. OMEx, which launched in April 2011, primarily emphasizes advances in novel optical materials, their properties, modeling, synthesis and fabrication techniques; how such materials contribute to novel optical behavior; and how they enable new or improved optical devices. For more information, visit OSA Publishing.

About The Optical Society

Founded in 1916, The Optical Society (OSA) is the leading professional organization for scientists, engineers, students and entrepreneurs who fuel discoveries, shape real-life applications and accelerate achievements in the science of light. Through world-renowned publications, meetings and membership initiatives, OSA provides quality research, inspired interactions and dedicated resources for its extensive global network of optics and photonics experts. For more information, visit osa.org/100.

Rebecca Andersen | EurekAlert!

Further reports about: E coli Nanoparticles bacteria gold nanoparticles nanometers tiny

More articles from Life Sciences:

nachricht A novel synthetic antibody enables conditional “protein knockdown” in vertebrates
20.08.2018 | Technische Universität Dresden

nachricht Climate Impact Research in Hannover: Small Plants against Large Waves
17.08.2018 | Leibniz Universität Hannover

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: It’s All in the Mix: Jülich Researchers are Developing Fast-Charging Solid-State Batteries

There are currently great hopes for solid-state batteries. They contain no liquid parts that could leak or catch fire. For this reason, they do not require cooling and are considered to be much safer, more reliable, and longer lasting than traditional lithium-ion batteries. Jülich scientists have now introduced a new concept that allows currents up to ten times greater during charging and discharging than previously described in the literature. The improvement was achieved by a “clever” choice of materials with a focus on consistently good compatibility. All components were made from phosphate compounds, which are well matched both chemically and mechanically.

The low current is considered one of the biggest hurdles in the development of solid-state batteries. It is the reason why the batteries take a relatively long...

Im Focus: Color effects from transparent 3D-printed nanostructures

New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference

Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...

Im Focus: Unraveling the nature of 'whistlers' from space in the lab

A new study sheds light on how ultralow frequency radio waves and plasmas interact

Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...

Im Focus: New interactive machine learning tool makes car designs more aerodynamic

Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.

When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...

Im Focus: Robots as 'pump attendants': TU Graz develops robot-controlled rapid charging system for e-vehicles

Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.

Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

LaserForum 2018 deals with 3D production of components

17.08.2018 | Event News

Within reach of the Universe

08.08.2018 | Event News

A journey through the history of microscopy – new exhibition opens at the MDC

27.07.2018 | Event News

 
Latest News

Quantum bugs, meet your new swatter

20.08.2018 | Information Technology

A novel synthetic antibody enables conditional “protein knockdown” in vertebrates

20.08.2018 | Life Sciences

Metamolds: Molding a mold

20.08.2018 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>