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.
This image depicts destructive electron extraction from bacterial membranes by plasmonic 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," says 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 says.
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.
Source: Applied Physics Letters
Stay prepared and protected with Infection Control Today's newsletter, delivering essential updates, best practices, and expert insights for infection preventionists.
Reducing Hidden Risks: Why Sharps Injuries Still Go Unreported
July 18th 2025Despite being a well-known occupational hazard, sharps injuries continue to occur in health care facilities and are often underreported, underestimated, and inadequately addressed. A recent interview with sharps safety advocate Amanda Heitman, BSN, RN, CNOR, a perioperative educational consultant, reveals why change is overdue and what new tools and guidance can help.
What Lies Beneath: Why Borescopes Are Essential for Verifying Surgical Instrument Cleanliness
July 16th 2025Despite their smooth, polished exteriors, surgical instruments often harbor dangerous contaminants deep inside their lumens. At the HSPA25 and APIC25 conferences, Cori L. Ofstead, MSPH, and her colleagues revealed why borescopes are an indispensable tool for sterile processing teams, offering the only reliable way to verify internal cleanliness and improve sterile processing effectiveness to prevent patient harm.
Getting Down and Dirty With PPE: Presentations at HSPA by Jill Holdsworth and Katie Belski
June 26th 2025In the heart of the hospital, decontamination technicians tackle one of health care’s dirtiest—and most vital—jobs. At HSPA 2025, 6 packed workshops led by experts Jill Holdsworth and Katie Belski spotlighted the crucial, often-overlooked art of PPE removal. The message was clear: proper doffing saves lives, starting with your own.
Unmasking Vaccine Myths: Dr Marschall Runge on Measles, Misinformation, and Public Health Solutions
May 29th 2025As measles cases climb across the US, discredited myths continue to undercut public trust in vaccines. In an exclusive interview with Infection Control Today, Michigan Medicine’s Marschall Runge, PhD, confronts misinformation head-on and explores how clinicians can counter it with science, empathy, and community engagement.
Silent Saboteurs: Managing Endotoxins for Sepsis-Free Sterilization
Invisible yet deadly, endotoxins evade traditional sterilization methods, posing significant risks during routine surgeries. Understanding and addressing their threat is critical for patient safety.