Rice, Ben-Gurion universities show laser-induced graphene kills bacteria, resists biofouling
Scientists at Rice University and Ben-Gurion University of the Negev (BGU) have discovered that laser-induced graphene (LIG) is a highly effective anti-fouling material and, when electrified, bacteria zapper.
In the top row, the growth of biofilm on surfaces with a solution containing Pseudomonas aeruginosa is observed on, from left, polyimide, graphite and laser-induced graphene surfaces. Green, red and blue represent live bacteria, dead bacteria and extracellular polymeric substances, respectively. At bottom, a sheet of polyimide burned on the left to leave laser-induced graphene shows the graphene surface nearly free of growth.
Credit: Arnusch Lab/Ben-Gurion University of the Negev
LIG is a spongy version of graphene, the single-atom layer of carbon atoms. The Rice lab of chemist James Tour developed it three years ago by burning partway through an inexpensive polyimide sheet with a laser, which turned the surface into a lattice of interconnected graphene sheets. The researchers have since suggested uses for the material in wearable electronics and fuel cells and for superhydrophobic or superhydrophilic surfaces.
According to their report in the American Chemical Society's ACS Applied Materials and Interfaces, LIG also protects surfaces from biofouling, the buildup of microorganisms, plants or other biological material on wet surfaces.
"This form of graphene is extremely resistant to biofilm formation, which has promise for places like water-treatment plants, oil-drilling operations, hospitals and ocean applications like underwater pipes that are sensitive to fouling," Tour said. "The antibacterial qualities when electricity is applied is a great additional benefit."
When used as electrodes with a small applied voltage, LIG becomes the bacterial equivalent of a backyard bug zapper. Tests without the charge confirmed what has long been known -- that graphene-based nanoparticles have antibacterial properties. When 1.1 to 2.5 volts were applied, the highly conductive LIG electrodes "greatly enhanced" those properties.
Under the microscope, the researchers watched as fluorescently tagged Pseudomonas aeruginosa bacteria in a solution with LIG electrodes above 1.1 volts were drawn toward the anode. Above 1.5 volts, the cells began to disappear and vanished completely within 30 seconds. At 2.5 volts, bacteria disappeared almost completely from the surface after one second.
The Rice lab partnered with Professor Christopher Arnusch, a lecturer at the BGU Zuckerberg Institute for Water Research who specializes in water purification. Arnusch's lab tested LIG electrodes in a bacteria-laden solution with 10 percent secondary treated wastewater and found that after nine hours at 2.5 volts, 99.9 percent of the bacteria were killed and the electrodes strongly resisted biofilm formation.
The researchers suspect bacteria may meet their demise through a combination of contact with the rough surface of LIG, the electrical charge and toxicity from localized production of hydrogen peroxide. The contact may be something like a knee hitting pavement, but in this case, the bacteria are all knee and the sharp graphene edges quickly destroy their membranes.
Fortunately, LIG's anti-fouling properties keep dead bacteria from accumulating on the surface, Tour said.
"The combination of passive biofouling inhibition and active voltage-induced microbial removal will likely make this a highly sought-after material for inhibiting the growth of troublesome natural fouling that plagues many industries," Tour said.
Swatantra Singh, a postdoctoral fellow at BGU, and Yilun Li, a graduate student at Rice, are lead authors of the paper. Co-authors are Avraham Be'er, a senior lecturer, and Yoram Oren, an emeritus professor, both of BGU. Tour is the T.T. and W.F. Chao Chair in Chemistry as well as a professor of computer science and of materials science and nanoengineering at Rice.
The research was supported by the United States?Israel Binational Science Foundation, the Canadian Associates of Ben-Gurion University of the Negev Quebec Region, the Israel Science Foundation, the Air Force Office of Scientific Research and its Multidisciplinary University Research Initiative.
Read the abstract at http://pubs.
This news release can be found online at http://news.
Follow Rice News and Media Relations via Twitter @RiceUNews
In this real-time video, Pseudomonas aeruginosa bacteria tagged with green fluorescent protein, which appear as bright dots, are drawn to an anode of laser-induced graphene, where they die. The anode at the top, which is separated from a cathode by a 100-micron channel, carries a small voltage that boosts its antibacterial properties. (Credit: Arnusch Lab/Ben-Gurion University of the Negev)
Tour Group: http://www.
Arnusch Lab: http://arnuschlab.
Wiess School of Natural Sciences: http://natsci.
Image for download:
In the top row, the growth of biofilm on surfaces with a solution containing Pseudomonas aeruginosa is observed on, from left, polyimide, graphite and laser-induced graphene surfaces. Green, red and blue represent live bacteria, dead bacteria and extracellular polymeric substances, respectively. At bottom, a sheet of polyimide burned on the left to leave laser-induced graphene shows the graphene surface nearly free of growth. (Credit: Arnusch Lab/Ben-Gurion University of the Negev)
Located on a 300-acre forested campus in Houston, Rice University is consistently ranked among the nation's top 20 universities by U.S. News & World Report. Rice has highly respected schools of Architecture, Business, Continuing Studies, Engineering, Humanities, Music, Natural Sciences and Social Sciences and is home to the Baker Institute for Public Policy. With 3,879 undergraduates and 2,861 graduate students, Rice's undergraduate student-to-faculty ratio is 6-to-1. Its residential college system builds close-knit communities and lifelong friendships, just one reason why Rice is ranked No. 1 for happiest students and for lots of race/class interaction by the Princeton Review. Rice is also rated as a best value among private universities by Kiplinger's Personal Finance. To read "What they're saying about Rice," go to http://tinyurl.
Editor's note: Links to video and a high-resolution image for download appear at the end of this release.
David Ruth | EurekAlert!
New catalyst controls activation of a carbon-hydrogen bond
21.11.2017 | Emory Health Sciences
The main switch
21.11.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau
The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
21.11.2017 | Physics and Astronomy
21.11.2017 | Physics and Astronomy
21.11.2017 | Life Sciences