Can silver promote the colonization of bacteria on medical devices?

June 28, 2013
SEM micrographs of S. epidermidis IE186 adhered to Ag-TiCN coatings after 2 h and 24 h period of contact: adhesion and biofilm formation to Ag/Ti = 0 a1) and a2) respectively; to Ag/Ti = 0.37 b1) and b2) respectively; to Ag/Ti = 0.62 c1) and c2) respectively. (C) I. Carvalho et al. Sci.

Biomaterials are increasingly being used to replace human organs and tissues. Since biomaterials are susceptible to microbial colonization, silver is often added to reduce the adhesion of bacteria to biomaterials and prevent infections. However, a recent study by researchers in Portugal suggests that – in one material – increasing levels of silver may indirectly promote bacterial adhesion.

Published in the journal Science and Technology of Advanced Materials, the study examined how surface properties affect the adhesion of Staphylococcus epidermidis bacteria to silver-titanium carbonitride (Ag-TiCN) coatings used for hip implant applications.

Normally found on human skin and mucous membranes, Staphyloccus epidermidis is one of the main pathogens associated with prosthetic device infections. A nanocomposite thin film, titanium carbonitride is non-toxic to and features excellent wear resistance, high hardness and good corrosion resistance.

Previous studies have shown that the adhesion of bacteria to biomaterials can be affected by the surface properties of bacteria, the surface properties of the material, and environmental conditions. In this study, Isabel Carvalho and her colleagues found that as the silver content of Ag-TiCN films increased from 0 to 15 percent, the surface roughness of the films decreased from 39 nm to 7 nm, while the hydrophobicity of the surface increased.

In addition, the study found that surfaces that were less rough and more hydrophobic were associated with greater . This suggests that increasing levels of silver in Ag-TiCN thin films may promote bacterial adhesion via a hydrophobic effect.

Explore further: Scientists evaluate different antimicrobial metals for use in water filters

More information: Carvalho, I. et al. Science and Technology of Advanced Materials, Vol. 14 (2013) p. 035009. DOI: 10.1088/1468-6996/14/3/035009

Related Stories

Spinning up antibacterial silver on glass

June 27, 2013

The antibacterial effects of silver are well established. Now, researchers at Yonsei University in Seoul, Republic of Korea, have developed a technique to coat glass with a layer of silver ions that can prevent growth of ...

New low-cost, transparent electrodes

June 27, 2013

Indium tin oxide (ITO) has become a standard material in light-emitting diodes, flat panel plasma displays, electronic ink and other applications because of its high performance, moisture resistance, and capacity for being ...

Recommended for you

For 2-D boron, it's all about that base

September 2, 2015

Rice University scientists have theoretically determined that the properties of atom-thick sheets of boron depend on where those atoms land.

Electrical circuit made of gel can repair itself

August 25, 2015

(Phys.org)—Scientists have fabricated a flexible electrical circuit that, when cut into two pieces, can repair itself and fully restore its original conductivity. The circuit is made of a new gel that possesses a combination ...

An engineered surface unsticks sticky water droplets

August 31, 2015

The leaves of the lotus flower, and other natural surfaces that repel water and dirt, have been the model for many types of engineered liquid-repelling surfaces. As slippery as these surfaces are, however, tiny water droplets ...

Scientists grow high-quality graphene from tea tree extract

August 21, 2015

(Phys.org)—Graphene has been grown from materials as diverse as plastic, cockroaches, Girl Scout cookies, and dog feces, and can theoretically be grown from any carbon source. However, scientists are still looking for a ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.