The rational design of nitric oxide selectivity in single-walled carbon nanotube near-infrared fluorescence sensors for biological detection

Abstract

A major challenge in the synthesis of nanotube or nanowire sensors is to impart selective analyte binding through means other than covalent linkages, which compromise electronic and optical properties. We synthesized a 3,4-diaminophenyl-functionalized dextran (DAP-dex) wrapping for single-walled carbon nanotubes (SWNTs) that imparts rapid and selective fluorescence detection of nitric oxide (NO), a messenger for biological signalling. The near-infrared (nIR) fluorescence of SWNT(DAP-dex) is immediately and directly bleached by NO, but not by other reactive nitrogen and oxygen species. This bleaching is reversible and shown to be caused by electron transfer from the top of the valence band of the SWNT to the lowest unoccupied molecular orbital of NO. The resulting optical sensor is capable of real-time and spatially resolved detection of NO produced by stimulating NO synthase in macrophage cells. We also demonstrate the potential of the optical sensor for in vivo detection of NO in a mouse model.

Real-time electrical detection of nitric oxide in biological systems with sub-nanomolar sensitivity

“…Indirect detection methodswhich rely on sensing secondary species such as nitrite and nitrate-are inherently ineffective for real-time detection. A number of direct detection methods such as electron paramagnetic resonance spectroscopy, chemiluminescence, mass spectrometry and fluorescence [8][9][10] are being developed for NO detection in biological systems. However, most of these methods either suffer from low sensitivity or require complicated sample preparation or measurement conditions that preclude real-time detection 7 .…”

Non-polydimethylsiloxane devices for oxygen-free flow lithography

“…Although SWNTs can be dispersed via covalent attachment of a polymer to their sidewall, this covalent functionalization disrupts the electronic structure and PL of the SWNT 53,54 . Therefore, it is crucial to stably disperse SWNTs with polymers in a non-covalent manner to retain the properties that make them effective optical sensors 55 . To overcome these difficulties, we non-covalently dispersed SWNTs by hydrophobic poly(9,9-di-ndodecylfluorenyl-2,7-diyl) polymer (PDDF) in toluene to preserve their sensing abilities.…”

Peptide secondary structure modulates single-walled carbon nanotube fluorescence as a chaperone sensor for nitroaromatics

“…The spectral changes differ among analytes, and different ðn;mÞ nanotube species exhibit individualized detection signatures, where the intensity and wavelength changes vary across SWNT species. This variation is illustrated here for the (7,5) and (11,3) species, which possess different diameters (0.829 vs. 1.014 nm), chiral angles (24.5°vs. 11.74°), and optical bandgaps (1.211 vs.…”

“…A mixture of SWNT encapsulated by bombolitin II, a variant of a bumblebee venom-derived amphiphilic peptide, was screened against a library of 42 analytes. The (7,5) nanotube species exhibits quenching due to several redox-active compounds (discussed later) as well as red shifts relative to the control peak wavelength, with slight concomitant intensity variation, in response to several nitroaromatic and nitro-group-containing nonaromatic compounds ( Fig. S1 and Table S1).…”

“…bionanotechnology | explosives detection | pesticides | spectroscopy | optical sensors S ingle-walled carbon nanotubes (SWNT) emit near-infrared (NIR) bandgap photoluminescence (PL) (1,2), which is highly responsive to its physical and chemical environment (3)(4)(5)(6). SWNT are unique among nanoscale sensor platforms in their ability to detect the adsorption of as few as a single molecule of an analyte (7,8).…”