Shanghai researchers develop new way to combat bacterial biofilm formation with titanium encrusted with gold nanoparticles
Bacteria love to colonize surfaces inside your body, but they have a hard time getting past your rugged, salty skin. Surgeries to implant medical devices often give such bacteria the opportunity needed to gain entry into the body cavity, allowing the implants themselves to act then as an ideal growing surface for biofilms.
A group of researchers at the Shanghai Institute of Ceramics in the Chinese Academy of Sciences are looking to combat these dangerous sub-dermal infections by upgrading your new hip or kneecap in a fashion appreciated since ancient times – adding gold. They describe the results of tests with a new antibacterial material they developed based on gold nanoparticles in the journal Applied Physics Letters, from AIP Publishing.
"Implant-associated infections have become a stubborn issue that often causes surgery failure," said Xuanyong Liu, the team's primary investigator at the Shanghai Institute of Ceramics. Designing implants that can kill bacteria while supporting bone growth, Liu said, is an efficient way to enhance in vivo osteointegration.
Titanium dioxide is able to kill bacteria itself due to its properties as a photocatalyst. When the metal is exposed to light, it becomes energetically excited by absorbing photons. This generates electron-hole pairs, turning titania into a potent electron acceptor that can destabilize cellular membrane processes by usurping their electron transport chain's terminal acceptor. The membrane is gradually destabilized by this thievery, causing the cell to leak out until it dies.
The dark conditions inside the human body, however, limit the bacteria-killing efficacy of titanium dioxide. Gold nanoparticles, though, can continue to act as anti-bacterial terminal electron acceptors under darkness, due to a phenomenon called localized surface plasmon resonance.
Surface plasmons are collective oscillations of electrons that occur at the interface between conductors and dielectrics – such as between gold and titanium dioxide. The localized electron oscillations at the nanoscale cause the gold nanoparticles to become excited and pass electrons to the titanium dioxide surface, thus allowing the particles to become electron acceptors.
Liu and his team electrochemically anodized titanium to form titanium dioxide nanotube arrays, and then further deposited the arrays with gold nanoparticles in a process called magnetron sputtering. The researchers then allowed Staphylococcus aureus and Escherichia coli to grow separately on the arrays -- both organisms were highly unsuccessful, exhibiting profuse membrane damage and cell leakage.
While silver nanoparticles have been previously explored as an antibacterial agent for in vivo transplants, they cause significant side effects such as cytotoxicity and organ damage, whereas gold is far more chemically stable, and thus more biocompatible.
"The findings may open up new insights for the better designing of noble metal nanoparticles-based antibacterial applications," Liu said.
Further research for Liu and his colleagues includes expanding the scope of experimental bacteria used and evaluating the arrays' in vivo efficacy in bone growth and integration.
The article, "Plasmonic gold nanoparticles modified titania nanotubes for antibacterial application" is authored by Jinhua Li, Huaijuan Zhou, Shi Qian, Ziwei Liu, Jingwei Feng, Ping Jin and Xuanyong Liu. It will appear in the journal Applied Physics Letters on July 1, 2014. After that date, it can be accessed at: http://scitation.aip.org/content/aip/journal/apl/104/26/10.1063/1.4885401
ABOUT THE JOURNAL
Applied Physics Letters features concise, rapid reports on significant new findings in applied physics. The journal covers new experimental and theoretical research on applications of physics phenomena related to all branches of science, engineering, and modern technology. See: http://apl.aip.org
Jason Socrates Bardi | Eurek Alert!
Astronomers identify a young heavyweight star in the Milky Way
22.08.2016 | University of Cambridge
Venus-like exoplanet might have oxygen atmosphere, but not life
19.08.2016 | Harvard-Smithsonian Center for Astrophysics
Waveguides are widely used for filtering, confining, guiding, coupling or splitting beams of visible light. However, creating waveguides that could do the same for X-rays has posed tremendous challenges in fabrication, so they are still only in an early stage of development.
In the latest issue of Acta Crystallographica Section A: Foundations and Advances , Sarah Hoffmann-Urlaub and Tim Salditt report the fabrication and testing of...
Electrochemists at TU Graz have managed to use monocrystalline semiconductor silicon as an active storage electrode in lithium batteries. This enables an integrated power supply to be made for microchips with a rechargeable battery.
Small electrical gadgets, such as mobile phones, tablets or notebooks, are indispensable accompaniments of everyday life. Integrated circuits in the interiors...
Recent findings indicating the possible discovery of a previously unknown subatomic particle may be evidence of a fifth fundamental force of nature, according...
A nanocrystalline material that rapidly makes white light out of blue light has been developed by KAUST researchers.
Malignant cancer cells not only proliferate faster than most body cells. They are also more dependent on the most important cellular garbage disposal unit, the proteasome, which degrades defective proteins. Therapies for some types of cancer exploit this dependence: Patients are treated with inhibitors, which block the proteasome. The ensuing pile-up of junk overwhelms the cancer cell, ultimately killing it. Scientists have now succeeded in determining the human proteasome’s 3D structure in unprecedented detail and have deciphered the mechanism by which inhibitors block the proteasome. Their results will pave the way to develop more effective proteasome inhibitors for cancer therapy.
In order to understand how cellular machines such as the proteasome work, it is essential to determine their three-dimensional structure in detail. With its...
12.08.2016 | Event News
02.08.2016 | Event News
29.07.2016 | Event News
23.08.2016 | Information Technology
23.08.2016 | Life Sciences
23.08.2016 | Earth Sciences