Tuesday, June 9, 2015

Graphene-based sensor capable of detecting cholera toxins for diagnosis of cancer

As recently reported by The Silicon Republic, researchers have developed a graphene-based sensor that is capable of detecting cholera toxins and providing earlier diagnosis of cancer and other diseases.

The sensor, known as a Surface Plasmon Resonance (SPR) sensor, is an established optical technique for medical diagnosis with high sensitivity and specificity, and can potentially be used for lab-on-a-chip sensors.

‘This type of sensing platform offers a large variety for medical diagnostics, since it can be adapted to almost any type of disease markers’ — Prof Georg Duesberg, at the AMBER labs at Trinity’s School of Chemistry [One of the guys behind the Infineon /Qimonda carbon / high-k DRAM Trench Capacitor technology http://www.hes.ei.tum.de/fileadmin/w00bjl/www/uploads/Aichmayr_VLSI07_talk06.pdf]

Noncovalently Functionalized Monolayer Graphene for Sensitivity Enhancement of Surface Plasmon Resonance Immunosensors 

 Meenakshi Singh †‡, Michael Holzinger, Maryam Tabrizian, Sinéad Winters, Nina C. Berner, Serge Cosnier, and Georg S. Duesberg

J. Am. Chem. Soc., 2015, 137 (8), pp 2800–2803 DOI: 10.1021/ja511512m


A highly efficient surface plasmon resonance (SPR) immunosensor is described using a functionalized single graphene layer on a thin gold film. The aim of this approach was two-fold: first, to amplify the SPR signal by growing graphene through chemical vapor deposition and, second, to control the immobilization of biotinylated cholera toxin antigen on copper coordinated nitrilotriacetic acid (NTA) using graphene as an ultrathin layer. The NTA groups were attached to graphene via pyrene derivatives implying π–π interactions. With this setup, an immunosensor for the specific antibody anticholera toxin with a detection limit of 4 pg mL–1 was obtained. In parallel, NTA polypyrrole films of different thicknesses were electrogenerated on the gold sensing platform where the optimal electropolymerization conditions were determined. For this optimized polypyrrole-NTA setup, the simple presence of a graphene layer between the gold and polymer film led to a significant increase of the SPR signal.

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