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Communications in Physics 18, 151-156 (2008)

On the new type of optical bio-sensor from dna-wrapped carbon nanotubes

D.P. Hung, D.L. Hien, D.T. Nga, N.V. Thanh, and N.A. Viet

Very recently, Daniel A. Heller et al. (Science 311, 508 (2006)) demonstrated that carbon nanotubes wrapped with DNA can be placed inside living cells and detect trace amounts of harmful contaminants using near infrared light. This discovery could lead to new types of optical sensors and biomarkers at the sub cellular level. We study a simple model of this new optical bio-sensor by wrapping a piece of double-stranded DNA around the surface of single-walled carbon nanotubes, in much the same fashion as a ribbon wraps around a cylinder. The DNA starts out wrapping around the nanotube with a certain shape that is defined by the negative charges along its backbone. Based on a theory of exciton in carbon nanotubes and we investigated transition of DNA secondary structure from the native, right-handed ”B” form to the alternate, left-handed ”Z” form. We’ve shown that our simple model can explain the working principle of this optical bio-sensor from DNA and carbon nanotubes.