A major challenge in the synthesis of nanotube or nanowire sensors is imparting selective analyte binding through means other than covalent linkages which compromise electronic and optical properties. We functionalize the nanointerface of single-walled carbon nanotube (SWNT) with the enzyme or the synthetic polymer as a selective recognition molecule for detection of adenosine 5�-triphosphate (ATP) or nitric oxide (NO) in living cells. For cellular detection of ATP that is used as a universal energy storage molecule in all micro-organisms, SWNT/luciferase hybrid is readily prepared by conjugating the enzyme to the surface of nanotube, and the resulting optical sensor is able to selectively and spatiotemporally detect ATP against AMP, ADP, CTP and GTP in living HeLa cells via the quenching of its near infrared (nIR) fluorescence. In addition, for detection of NO that plays a important role as an intracellular and intercellular messenger for signaling, a 3,4-diaminophenyl-functionalized dextran (DAP-dex) wrapping for SWNT, which imparts rapid and selective fluorescence detection of NO, is synthesized. The near infrared (nIR) fluorescence of SWNT/DAP-dex hybrid is immediately and directly bleached by NO, but not by other reactive nitrogen and oxygen species. The resulting optical sensor is capable of real-time and spatially resolved detection of NO produced by stimulating NO synthase (iNOS) in macrophage cells. The nanointerface modulation of SWNT optical sensors in this way to provide temporal and spatial information in real time in living organisms underscores their potential for biological applications.

Nanointerface modulation of single-walled carbon nanotube for detection of ATP and nitric oxide in living cells

240th National Meeting (2010)

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