Carbon nanotube-based biosensors

Abstract

An easy and rapid detection of hazardous compounds is crucial for making on-the-spotirreversible decisions at airport security gates, luggage storage rooms, and other crowdedpublic places, such as stadia, concert halls, etc.In the present study we carried out a preliminary investigation into the possibility ofutilizing as advanced nano-biosensors a mutant form of the bovine odorant-binding protein(bOBP) immobilized onto carbon nanotubes. In particular, after immobilization of theprotein on the carbon nanotubes we developed a competitive resonance energy transfer(RET) assay between the protein tryptophan residues located at the positions 17 and 133(W17 and W133) and the 1-amino-anthracene (AMA), a molecule that fits in the bindingsite of bOBP. The bOBP–AMA complex emitted light in the visible region upon excitationof the Trp donors. However, the addition of an odorant molecule to the bOBP–AMAcomplex displaced AMA from the binding site making the carbon nanotubes colorless.The results presented in this work are very promising for the realization of a color on/ coloroff b-OBP-based biosensor for the initial indication of hazardous compounds in theenvironment.