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A graphene-based sensor applied to the tooth surface unveils bacterial diseases. Nanoplatelets made of this material displayed anti-pathogenic properties. Graphene is offering thousands of useful applications.

Think about smart fabrics that recognize noxious substances – their use for special working outfits is obvious – as well as about materials for controlled drug release into the human body, or even testers for the quality of natural hair for extensions.

While studying the safe use of these materials, researchers at the new Lab for Nanotechnologies and Nanosciences of the La Sapienza University (SNN-Lab) made an amazing discovery: the graphene nanoplatelets used for the test are not harmful for the health of living beings, and can even counter the action of bacteria, including pathogenic ones, on man.

The researchers infected the Caenorhabditis elegans worm – a harmless soil dweller, thoroughly studied by geneticists – with Pseudomonas aeruginosa bacteria, which cause diseases in man. Then they studied the localization of graphene nanoparticles inside the nematode (this is the scientific name of the worm) after ingestion. No acute or chronic toxicity was observed in the nanoparticles, which rather displayed good antibacterial properties and improved the “life expectancy” of the worms.

The used in vivo system will suggest to researchers what kinds of controls should be performed at a higher practical usage level on mammals and on man.

Graphite nanoplatelets (GNPs) are nanoplatelets, a few microns wide and 1 to 10 nm thick, made of few overlapped layers of graphene. These materials allow a broad variety of applications, from nanomedicine to biosensors to fillers for multifunctional nanocomposites with excellent mechanical, thermal, and electric/electromagnetic properties.
The GNPs can be obtained by means of a synthesis process designed* by the Lab of Nanotechnologies and Nanosciences of the La Sapienza University, which can be easily developed on a large scale at very low costs.

In the US, Michael McAlpine of the Princeton University developed a new kind of remote chemical sensor capable to broadcast the messages of the … molar teeth, reporting the presence of bacteria in the individual cells by means of the wireless technology.

The sensor is the result of a new synergy among smart materials. This technology allows wireless communication with a detector and, for the first time, a device was directly interfaced with biological tissue.
The sensor was printed on a small graphene grid placed, in turn, on a sheer silk layer, which acts as a platform to start the transfer of graphene to a broad variety of supports (teeth, as well as soft tissues).
After placing the silk-graphene device on the tooth, the area was rinsed with water, which dissolved the silk support and left the ultra-thin circuit in place. The unique properties of graphene ensured perfect adherence of the material to the surface. The next step was to attach bifunctional peptides to the graphene base, followed by the use of an antimicrobial protein (AMP), which has strong affinity with the three main bacterial strains.
When the bacteria bound with the protein, the sensor, interrogated via an external antenna, indicated the bacterial concentrations. This finding is important to promptly identify and remove concentrations even at single cell level, and in this respect the flexibility and non-toxic nature of graphene play an important role for future perspectives.

*This work is the result of cooperation between the teams coordinated by Claudio Palleschi of the “Charles Darwin” Department of Biology and Biotechnologies, M. Sabrina Sarto of the Astronautical, Electric, and Energy Engineering of the Lab, and Maria L. Santarelli of the Department of Chemical Engineering, Materials, and the Environment, all part of the Centre for Research on Nanotechnologies Applied to Engineering of the La Sapienza University (CNIS).

Andrea Santillana
Published on Monday, November 5, 2012


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