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Preparation of Graphene-Modified Acupuncture Needle and Its Application in Detecting Neurotransmitters.

Tang L, Du D, Yang F, Liang Z, Ning Y, Wang H, Zhang GJ - Sci Rep (2015)

Bottom Line: Subsequently, the G-AN was obtained by cyclic voltammetry reduction of a graphene oxide solution on the surface of the AuNPs.What's more, the G-AN was further used for detection of dopamine (DA) with a limit of detection of 0.24 μM.This novel G-AN exhibited a good sensitivity and selectivity, and could realize direct detection of DA in human serum.

View Article: PubMed Central - PubMed

Affiliation: School of Laboratory Medicine, Hubei University of Chinese Medicine, 1 Huangjia Lake West Road, Wuhan 430065, China.

ABSTRACT
We report a unique nanosensing platform by combining modern nanotechnology with traditional acupuncture needle to prepare graphene-modified acupuncture needle (G-AN), and using it for sensitive detection of neurotransmitters via electrochemistry. An electrochemical deposition method was employed to deposit Au nanoparticles (AuNPs) on the tip surface of the traditional acupuncture needle, while the other part of the needle was coated with insulation paste. Subsequently, the G-AN was obtained by cyclic voltammetry reduction of a graphene oxide solution on the surface of the AuNPs. To investigate the sensing property of the G-AN, pH dependence was measured by recording the open circuit potential in the various pH buffer solutions ranging from 2.0 to 10.0. What's more, the G-AN was further used for detection of dopamine (DA) with a limit of detection of 0.24 μM. This novel G-AN exhibited a good sensitivity and selectivity, and could realize direct detection of DA in human serum.

No MeSH data available.


Related in: MedlinePlus

(A) Time dependence of the open circuit potential of the G-AN in PBS solutions at different pH values, (B) Plots of the potential versus various pH. Y = 0.0209–0.0299X, R2 = 0.9921.
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f3: (A) Time dependence of the open circuit potential of the G-AN in PBS solutions at different pH values, (B) Plots of the potential versus various pH. Y = 0.0209–0.0299X, R2 = 0.9921.

Mentions: The pH dependence of the bare acupuncture needle, the AuNPs/acupuncture needle and the G-AN was measured by recording the open circuit potential in various pH buffer solutions ranging from 2.0 to 10.0, respectively. Before each measurement, the needles were immersed into ultrapure water in order to ensure the same starting conditions. For bare needle, the curve showed a response, but was lack of linearity (Fig. S2 (A, B)). For the AuNPs/acupuncture needle, the response curve was disordered in pH range of 7.0–10.0, and was not linear either (Fig. S2 (C, D)). However, after graphene was modified, the response curve showed a good linearity as it is well known that carbon materials would give rise to a pH response38, as shown in Fig. 3A. It was observed that the signal stabilized within a few seconds and kept stable during the measured time. The potential signals decreased when the value of pH were increased, which is accordance with some others’ pH sensors3435. The excellent performance was also showed in terms of linearity (Y = 0.0209–0.0299X, R2 = 0.9921) (Fig. 3B). The above-mentioned linear equation exhibited that the linear pH response of sensitivity was 29.9 mV/pH, which was not the Nernstian-like behavior. The reasons for this phenomenon may probably be attributed to the absence of ionizable carboxylic and hydroxyl groups on the surface of G-AN (the hydroxyl groups and residual carboxylic groups on the surface of reduced GO have not been activated, and can not well undergo protonation and deprotonation with pH), which is in good agreement with the results reported previously37. However, compared with the bare acupuncture needle and the AuNPs-modified acupuncture needle, the G-AN can be protonated and deprotonated with pH for the presence of graphene. As a result, these results indicate that the G-AN is more suitable for detection of biological signal molecule in organisms than the acupuncture needle without any modification and the acupuncture needle modified just with AuNPs.


Preparation of Graphene-Modified Acupuncture Needle and Its Application in Detecting Neurotransmitters.

Tang L, Du D, Yang F, Liang Z, Ning Y, Wang H, Zhang GJ - Sci Rep (2015)

(A) Time dependence of the open circuit potential of the G-AN in PBS solutions at different pH values, (B) Plots of the potential versus various pH. Y = 0.0209–0.0299X, R2 = 0.9921.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4481527&req=5

f3: (A) Time dependence of the open circuit potential of the G-AN in PBS solutions at different pH values, (B) Plots of the potential versus various pH. Y = 0.0209–0.0299X, R2 = 0.9921.
Mentions: The pH dependence of the bare acupuncture needle, the AuNPs/acupuncture needle and the G-AN was measured by recording the open circuit potential in various pH buffer solutions ranging from 2.0 to 10.0, respectively. Before each measurement, the needles were immersed into ultrapure water in order to ensure the same starting conditions. For bare needle, the curve showed a response, but was lack of linearity (Fig. S2 (A, B)). For the AuNPs/acupuncture needle, the response curve was disordered in pH range of 7.0–10.0, and was not linear either (Fig. S2 (C, D)). However, after graphene was modified, the response curve showed a good linearity as it is well known that carbon materials would give rise to a pH response38, as shown in Fig. 3A. It was observed that the signal stabilized within a few seconds and kept stable during the measured time. The potential signals decreased when the value of pH were increased, which is accordance with some others’ pH sensors3435. The excellent performance was also showed in terms of linearity (Y = 0.0209–0.0299X, R2 = 0.9921) (Fig. 3B). The above-mentioned linear equation exhibited that the linear pH response of sensitivity was 29.9 mV/pH, which was not the Nernstian-like behavior. The reasons for this phenomenon may probably be attributed to the absence of ionizable carboxylic and hydroxyl groups on the surface of G-AN (the hydroxyl groups and residual carboxylic groups on the surface of reduced GO have not been activated, and can not well undergo protonation and deprotonation with pH), which is in good agreement with the results reported previously37. However, compared with the bare acupuncture needle and the AuNPs-modified acupuncture needle, the G-AN can be protonated and deprotonated with pH for the presence of graphene. As a result, these results indicate that the G-AN is more suitable for detection of biological signal molecule in organisms than the acupuncture needle without any modification and the acupuncture needle modified just with AuNPs.

Bottom Line: Subsequently, the G-AN was obtained by cyclic voltammetry reduction of a graphene oxide solution on the surface of the AuNPs.What's more, the G-AN was further used for detection of dopamine (DA) with a limit of detection of 0.24 μM.This novel G-AN exhibited a good sensitivity and selectivity, and could realize direct detection of DA in human serum.

View Article: PubMed Central - PubMed

Affiliation: School of Laboratory Medicine, Hubei University of Chinese Medicine, 1 Huangjia Lake West Road, Wuhan 430065, China.

ABSTRACT
We report a unique nanosensing platform by combining modern nanotechnology with traditional acupuncture needle to prepare graphene-modified acupuncture needle (G-AN), and using it for sensitive detection of neurotransmitters via electrochemistry. An electrochemical deposition method was employed to deposit Au nanoparticles (AuNPs) on the tip surface of the traditional acupuncture needle, while the other part of the needle was coated with insulation paste. Subsequently, the G-AN was obtained by cyclic voltammetry reduction of a graphene oxide solution on the surface of the AuNPs. To investigate the sensing property of the G-AN, pH dependence was measured by recording the open circuit potential in the various pH buffer solutions ranging from 2.0 to 10.0. What's more, the G-AN was further used for detection of dopamine (DA) with a limit of detection of 0.24 μM. This novel G-AN exhibited a good sensitivity and selectivity, and could realize direct detection of DA in human serum.

No MeSH data available.


Related in: MedlinePlus