Effect of Reductive Dithiothreitol and Trolox on Nitric Oxide Quenching of Single-Walled Carbon Nanotubes

Abstract

Semiconducting single-walled carbon nanotubes (SWCNTs) fluoresce in the near-infrared and are promising as optical sensors when functionalized to enable analyte recognition. SWCNT sensors with enhanced fluorescence emission have been hypothesized to have greater sensitivities, and reductive brightening reagents, such as dithiothreitol (DTT) and Trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid), enhance SWCNT brightness. We examine the effect of Trolox and DTT on the sensitivity of a nitric oxide (NO) sensor and report that the NO sensitivity is reduced. The NO adsorption rate decreases from 0.0007 ± 0.00003 to 0.000 3± 0.00003 and 0.0004 ± 0.0001 s–1 μM–1 upon pretreatment of 1 mM Trolox and 1 mM DTT, respectively. These results are consistent with a model where Trolox and DTT are competitive binding agents with NO, occupying one of a finite number of available SWCNT binding sites and altering the NO binding strength. In the use of brightening agents, a trade-off is predicted between signal intensity and analyte sensitivity.

Impact of Redox-Active Molecules on the Fluorescence of Polymer-Wrapped Carbon Nanotubes

“…The different redox-active molecules that were tested have different structures but sometimes similar redox potentials such as ascorbic acid, trolox, or epinephrine. − …”

Origin of the Surfactant‐Dependent Redox Chemistry of Single‐Wall Carbon Nanotubes

“…The attenuated spectral intensities of the oxidized SWCNTs were restored by the addition of reductants, that is, TCEP‐HCl and DTT (Figure ). DTT as well as other reductants, such as Trolox and β‐mercaptoethanol, have a reducing effect on the SWCNTs dispersed by using deoxyribonucleic acids (DNA) . The reduction, however, was detectable almost exclusively through the restoration of fluorescent intensities but not absorption intensities; that is, insignificant absorbance changes were observed under the conditions .…”

“…DTT as well as other reductants, such as Trolox and b-mercaptoethanol, have ar educing effect on the SWCNTsd ispersed by using deoxyribonucleic acids (DNA). [49][50][51][52] The reduction, however,w as detectable almost exclusively through the restoration of fluorescent intensitiesb ut not absorptioni ntensities;t hat is, insignificant absorbance changes were observed under the conditions. [52] In addition, notet hat the fluorescent intensities are more sensitivet ot he alteration of optical properties of the SWCNTst han the absorptioni ntensities.…”

Influence of cysteine doping on photoluminescence intensity from semiconducting single-walled carbon nanotubes

“…Oxygen molecules present in water can form p-defects on the nanotube surface, which serve as effective traps for excitons [8,9]. Passivation of these defects by some organic molecules like dithiothreitol (DDT) or Trolox enhances the QY of the nanotube PL [9][10][11][12]. It was supposed that these reducing agents donate electrons to defective sites on the nanotube surface [9].…”