three different porphyrin systems carrying β-D-galactose (SWNT-FET porphyrin 29Gal), α-L-fucose (SWNT-FET porphyrin 30-Fuc), and α-D-mannose epitopes (SWNTFET porphyrin 31-Man) displayed on SWNTs and the corresponding bacterial PA-IL,
PA-IIL, and plant Con A lectins, respectively (Fig. 9). The results indicated that
substantial responses were induced by the specific interactions between the
saccharides and their cognate lectins, without nonspecific adsorption on Znporphyrins or SWNTs. This observation corroborated that the glycoconjugate
functionalization served the dual purpose of selectively detecting lectin binding as
well as preventing nonspecific protein binding to SWNTs. Moreover, the sensitivity
and the selectivity of the methodology was demonstrated, with detection limit of
SWNT-FET devices being comparable to more traditional techniques used for lectin
detection such as optical microarray, electrochemical surface plasmon resonance
(SPR), electrochemical impedance spectroscopy, or voltammetric and colorimetric
protocols. The IC 50 values compared well with those previously determined by SPR or
by hemagglutination inhibition assay (HIA), thus confirming that glycosylated
SWNT-FETs could be used for the quantitative determination of affinity constants.
The same group also compared the performance of these SWNT-FET devices with
similarly functionalized chemically converted graphene-based FET systems (CCGFET porphyrin 29-Gal, CCG-FET porphyrin 30-Fuc, and CCG-FET porphyrin 31-Man),
also adding pyrene-terminated appendages to extend the applicability of these
Fig. 9 (a) Representation of glycoconjugate-functionalized SWNT-field effect transistor (SWNTFET) as sensitive lectin nanodetection platforms. (b) Structures of porphyrin- and pyrene-based
glycoconjugates, together with illustrations of nanocarbon FET devices. Adapted with permission
from Mcmillan Publishers Ltd from [77]. Copyright 2010 American Chemical Society
Applications of Glyconanoparticles as “Sweet” Glycobiological. . .
315
PA-IIL, and plant Con A lectins, respectively (Fig. 9). The results indicated that
substantial responses were induced by the specific interactions between the
saccharides and their cognate lectins, without nonspecific adsorption on Znporphyrins or SWNTs. This observation corroborated that the glycoconjugate
functionalization served the dual purpose of selectively detecting lectin binding as
well as preventing nonspecific protein binding to SWNTs. Moreover, the sensitivity
and the selectivity of the methodology was demonstrated, with detection limit of
SWNT-FET devices being comparable to more traditional techniques used for lectin
detection such as optical microarray, electrochemical surface plasmon resonance
(SPR), electrochemical impedance spectroscopy, or voltammetric and colorimetric
protocols. The IC 50 values compared well with those previously determined by SPR or
by hemagglutination inhibition assay (HIA), thus confirming that glycosylated
SWNT-FETs could be used for the quantitative determination of affinity constants.
The same group also compared the performance of these SWNT-FET devices with
similarly functionalized chemically converted graphene-based FET systems (CCGFET porphyrin 29-Gal, CCG-FET porphyrin 30-Fuc, and CCG-FET porphyrin 31-Man),
also adding pyrene-terminated appendages to extend the applicability of these
Fig. 9 (a) Representation of glycoconjugate-functionalized SWNT-field effect transistor (SWNTFET) as sensitive lectin nanodetection platforms. (b) Structures of porphyrin- and pyrene-based
glycoconjugates, together with illustrations of nanocarbon FET devices. Adapted with permission
from Mcmillan Publishers Ltd from [77]. Copyright 2010 American Chemical Society
Applications of Glyconanoparticles as “Sweet” Glycobiological. . .
315