31 May 2012

Biosensor – a transfer picture

A wireless graphene bacteria detector was applied to the teeth

<url>Engineers from Princeton University have created a graphene-based wireless biosensor that can be fixed to biological surfaces, such as teeth.

The sensitivity of the device is sufficient to detect individual bacterial cells. The work (Mannoor et al., Graphene-based wireless bacteria detection on tooth enamel) is published in the journal Nature Communications, its summary can be read on the university's website (Wireless 'tooth tattoo' detects harmful bacteria).

To create the device, the authors used a substrate of soluble silk. Natural silk was dissolved, and then a thin film was obtained from it by drying. Bacteria-sensitive graphene and a thin film of gold, from which contacts and an antenna were made, were applied to the substrate.

The device received energy using an antenna. The same antenna was used to transmit signals from a graphene detector.

After assembly, the device was applied to biological surfaces – on the skin on the volunteers' hand or on a cow's tooth: the authors say that in order to apply the sensor to human teeth, it will have to be reduced, which is not yet possible due to the minimum effective size of the antenna.

After washing with water, the silk substrate dissolved, and the gold film, together with graphene, was fixed to the surface – photo on the right, Princeton/Michael McAlpine.

(The pictures from the article in Nature Communications show that a thin stream of water does not wash off the sensor – VM glued to the skin.)

According to the authors of the study, a graphene detector can potentially be used to detect various substances. In this case, in order to make monatomic carbon sensitive specifically to bacteria, peptides with affinity for the surface of microbial cells were applied to it.

The information from the wireless detector was read using an antenna. The distance from the sensor antenna to the receiving antenna should not exceed one centimeter, but the authors hope to increase the minimum distance over time.

Sensors based on graphene use its high sensitivity to the addition of foreign substances. In the presence of specific adapters (in the role of which, for example, antibodies can act), such sensors will be able to detect toxins, explosive molecules or even odors.

Portal "Eternal youth" http://vechnayamolodost.ru31.05.2012

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