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D-(+)-galactose-conjugated single-walled carbon nanotubes as new chemical probes for electrochemical biosensors for the cancer marker galectin-3.

Park YK, Bold B, Lee WK, Jeon MH, An KH, Jeong SY, Shim YK - Int J Mol Sci (2011)

Bottom Line: To investigate the binding of galectin-3 to the d-(+)-galactose-conjugated SWCNTs, an electrochemical biosensor was fabricated by using molybdenum electrodes.The binding affinities of the conjugated SWCNTs to galectin-3 were quantified using electrochemical sensitivity measurements based on the differences in resistance together with typical I-V characterization.The electrochemical sensitivity measurements of the d-(+)-galactose-conjugated SWCNTs differed significantly between the samples with and without galectin-3.

View Article: PubMed Central - PubMed

Affiliation: Department of Nano System Engineering, Inje University, Gimhae, 612-749, Korea; E-Mails: immergreen@dreamwiz.com (Y.K.P.); bayarma_sbmt@yahoo.com (B.B.); wlee@inje.ac.kr (W.K.L.); mjeon@inje.ac.kr (M.H.J.).

ABSTRACT
D-(+)-Galactose-conjugated single-walled carbon nanotubes (SWCNTs) were synthesized for use as biosensors to detect the cancer marker galectin-3. To investigate the binding of galectin-3 to the d-(+)-galactose-conjugated SWCNTs, an electrochemical biosensor was fabricated by using molybdenum electrodes. The binding affinities of the conjugated SWCNTs to galectin-3 were quantified using electrochemical sensitivity measurements based on the differences in resistance together with typical I-V characterization. The electrochemical sensitivity measurements of the d-(+)-galactose-conjugated SWCNTs differed significantly between the samples with and without galectin-3. This indicates that d-(+)-galactose-conjugated SWCNTs are potentially useful electrochemical biosensors for the detection of cancer marker galectin-3.

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Related in: MedlinePlus

Typical graphical data for (a) I-V measurements and (b) the sensitivities of samples with or without galectin-3. The typical I-V characteristics were measured using the prepared Mo electrodes. SWCNTs dispersed between the Mo electrodes were exposed to various concentrations of galectin-3 in PBS (two-fold serial dilutions from 0.5 to 0.0156 μg/100 μL). The results were obtained from three different experiments. Each bar represents the mean standard deviation.
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f4-ijms-12-02946: Typical graphical data for (a) I-V measurements and (b) the sensitivities of samples with or without galectin-3. The typical I-V characteristics were measured using the prepared Mo electrodes. SWCNTs dispersed between the Mo electrodes were exposed to various concentrations of galectin-3 in PBS (two-fold serial dilutions from 0.5 to 0.0156 μg/100 μL). The results were obtained from three different experiments. Each bar represents the mean standard deviation.

Mentions: The sensitivity of a biosensor using SWCNTs dispersed between two Mo electrodes was defined as the difference in the resistance between sample solutions with or without galectin-3 and blank controls. The sensitivity was calculated using the formula [(Rm − R0)/R0], where Rm and R0 are the resistance of the samples with or without galectin-3 and that of the blank controls, respectively. Typical I-V measurements and sensitivities using the samples with or without galectin-3 are shown in Figure 4; the currents decreased after galectin-3 was bound to the d-(+)-galactose-conjugated SWCNTs based on the p-type characteristics of SWCNT-FETs [14,31]. Taking into account the fact that the SWCNTs exhibited p-type electronic behavior before adsorption of galectin-3, presumably due to doping from environmental oxygen, the current change after exposure to galectin-3 indicates an electron transfer from galectin-3 to the SWCNTs. A hybrid of galectin-3 and SWCNTs has been shown to be sensitive to the presence of d-(+)-galactose, which specifically binds to galectin-3, resulting in a decreased current. In this study, the sensitivity of the sample without galectin-3 was 18.7, whereas for samples with galectin-3, the maximum sensitivity was 31.3 (0.3125 μg/100 μL). The sensitivity of the samples increased with the galectin-3 concentration over a limited concentration range (0.0156–0.03125 μg/100 μL) (Figure 4b). From these results, we found that the resistance increased with the concentration of galectin-3 bound to the d-(+)-galactose-conjugated SWCNTs, and that the resistance was not further increased with concentration of galectin-3 higher than 0.03125 μg/100 μL because of the saturation of the majority carriers on the SWCNTs by the action of galectin-3 as an electron donor [14,31]. Finally, we confirmed that the sensitivity for the samples with galectin-3 increased with the concentration of galectin-3 in the binding reaction over a limited concentration range. These observations imply that d-(+)-galactose-conjugated SWCNTs are potentially useful as electrochemical nanobiosensors for the cancer marker galectin-3.


D-(+)-galactose-conjugated single-walled carbon nanotubes as new chemical probes for electrochemical biosensors for the cancer marker galectin-3.

Park YK, Bold B, Lee WK, Jeon MH, An KH, Jeong SY, Shim YK - Int J Mol Sci (2011)

Typical graphical data for (a) I-V measurements and (b) the sensitivities of samples with or without galectin-3. The typical I-V characteristics were measured using the prepared Mo electrodes. SWCNTs dispersed between the Mo electrodes were exposed to various concentrations of galectin-3 in PBS (two-fold serial dilutions from 0.5 to 0.0156 μg/100 μL). The results were obtained from three different experiments. Each bar represents the mean standard deviation.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3116166&req=5

f4-ijms-12-02946: Typical graphical data for (a) I-V measurements and (b) the sensitivities of samples with or without galectin-3. The typical I-V characteristics were measured using the prepared Mo electrodes. SWCNTs dispersed between the Mo electrodes were exposed to various concentrations of galectin-3 in PBS (two-fold serial dilutions from 0.5 to 0.0156 μg/100 μL). The results were obtained from three different experiments. Each bar represents the mean standard deviation.
Mentions: The sensitivity of a biosensor using SWCNTs dispersed between two Mo electrodes was defined as the difference in the resistance between sample solutions with or without galectin-3 and blank controls. The sensitivity was calculated using the formula [(Rm − R0)/R0], where Rm and R0 are the resistance of the samples with or without galectin-3 and that of the blank controls, respectively. Typical I-V measurements and sensitivities using the samples with or without galectin-3 are shown in Figure 4; the currents decreased after galectin-3 was bound to the d-(+)-galactose-conjugated SWCNTs based on the p-type characteristics of SWCNT-FETs [14,31]. Taking into account the fact that the SWCNTs exhibited p-type electronic behavior before adsorption of galectin-3, presumably due to doping from environmental oxygen, the current change after exposure to galectin-3 indicates an electron transfer from galectin-3 to the SWCNTs. A hybrid of galectin-3 and SWCNTs has been shown to be sensitive to the presence of d-(+)-galactose, which specifically binds to galectin-3, resulting in a decreased current. In this study, the sensitivity of the sample without galectin-3 was 18.7, whereas for samples with galectin-3, the maximum sensitivity was 31.3 (0.3125 μg/100 μL). The sensitivity of the samples increased with the galectin-3 concentration over a limited concentration range (0.0156–0.03125 μg/100 μL) (Figure 4b). From these results, we found that the resistance increased with the concentration of galectin-3 bound to the d-(+)-galactose-conjugated SWCNTs, and that the resistance was not further increased with concentration of galectin-3 higher than 0.03125 μg/100 μL because of the saturation of the majority carriers on the SWCNTs by the action of galectin-3 as an electron donor [14,31]. Finally, we confirmed that the sensitivity for the samples with galectin-3 increased with the concentration of galectin-3 in the binding reaction over a limited concentration range. These observations imply that d-(+)-galactose-conjugated SWCNTs are potentially useful as electrochemical nanobiosensors for the cancer marker galectin-3.

Bottom Line: To investigate the binding of galectin-3 to the d-(+)-galactose-conjugated SWCNTs, an electrochemical biosensor was fabricated by using molybdenum electrodes.The binding affinities of the conjugated SWCNTs to galectin-3 were quantified using electrochemical sensitivity measurements based on the differences in resistance together with typical I-V characterization.The electrochemical sensitivity measurements of the d-(+)-galactose-conjugated SWCNTs differed significantly between the samples with and without galectin-3.

View Article: PubMed Central - PubMed

Affiliation: Department of Nano System Engineering, Inje University, Gimhae, 612-749, Korea; E-Mails: immergreen@dreamwiz.com (Y.K.P.); bayarma_sbmt@yahoo.com (B.B.); wlee@inje.ac.kr (W.K.L.); mjeon@inje.ac.kr (M.H.J.).

ABSTRACT
D-(+)-Galactose-conjugated single-walled carbon nanotubes (SWCNTs) were synthesized for use as biosensors to detect the cancer marker galectin-3. To investigate the binding of galectin-3 to the d-(+)-galactose-conjugated SWCNTs, an electrochemical biosensor was fabricated by using molybdenum electrodes. The binding affinities of the conjugated SWCNTs to galectin-3 were quantified using electrochemical sensitivity measurements based on the differences in resistance together with typical I-V characterization. The electrochemical sensitivity measurements of the d-(+)-galactose-conjugated SWCNTs differed significantly between the samples with and without galectin-3. This indicates that d-(+)-galactose-conjugated SWCNTs are potentially useful electrochemical biosensors for the detection of cancer marker galectin-3.

Show MeSH
Related in: MedlinePlus