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Single-step cycle pulse operation of the label-free electrochemiluminescence immunosensor based on branched polypyrrole for carcinoembryonic antigen detection.

Zhu W, Wang Q, Ma H, Lv X, Wu D, Sun X, Du B, Wei Q - Sci Rep (2016)

Bottom Line: Moreover, 1-butylpyridinium tetrafluroborate ([BPy]BF4) were used to disperse luminol functional-Au NPs@polypyrrole nanocomposites, resulting in the film-formation of composites on the electrode, which could improve the stability of immunosensor.The proposed method presents good ECL response for the detection of CEA allowing a wide linear range from 0.01 pg/mL to 10 ng/mL and a limit of detection as low as 3 fg/mL.The immunosensor would be a promising tool in the early diagnosis of CEA due to its high sensitivity, simplicity and cost-effective.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Chemical Sensing &Analysis in Universities of Shandong, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, P.R. China.

ABSTRACT
A novel label-free electrochemiluminescence (ECL) immunosensor based on luminol functional-Au NPs@polypyrrole has been developed for the detection of carcinoembryonic antigen (CEA). In this work, polypyrrole prepared by chemical polymerization provided a large surface area to load amounts of gold nanoparticles (Au NPs). Au NPs could not only attach abundant luminol for the enhancement of ECL signal, but also provide a friendly microenvironment for the immobilization of antibodies. Moreover, 1-butylpyridinium tetrafluroborate ([BPy]BF4) were used to disperse luminol functional-Au NPs@polypyrrole nanocomposites, resulting in the film-formation of composites on the electrode, which could improve the stability of immunosensor. In particular, employment of single-step cycle pulse could limit the consecutive reaction between luminol and H2O2 efficiently, thus leading to stable and strong signals. The proposed method presents good ECL response for the detection of CEA allowing a wide linear range from 0.01 pg/mL to 10 ng/mL and a limit of detection as low as 3 fg/mL. The immunosensor would be a promising tool in the early diagnosis of CEA due to its high sensitivity, simplicity and cost-effective.

No MeSH data available.


(A) EIS of the electrode at different modification stages: (a) bare GCE, (b) luminol-Au NPs@PPy/GCE, (c) anti-CEA-luminol-Au NPs@PPy/GCE, (d) BSA/anti-CEA-luminol-Au NPs@PPy/GCE and (e) CEA/BSA/anti-CEA-luminol-Au NPs@PPy/GCE measured in ferricyanide solutions (Fe(CN)63−/4−, 2.5 mM, pH 7.4). (B) ECL intensity profiles of the luminol-Au NPs@PPy/GCE (curve a), anti-CEA-luminol-Au NPs@PPy/GCE (curve b), BSA/anti-CEA-luminol-Au NPs@PPy/GCE (curve c) and CEA/BSA/anti-CEA-luminol-Au NPs@PPy/GCE (curve d) measured in CBS (pH 10.4) containing 25 mM H2O2.
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f3: (A) EIS of the electrode at different modification stages: (a) bare GCE, (b) luminol-Au NPs@PPy/GCE, (c) anti-CEA-luminol-Au NPs@PPy/GCE, (d) BSA/anti-CEA-luminol-Au NPs@PPy/GCE and (e) CEA/BSA/anti-CEA-luminol-Au NPs@PPy/GCE measured in ferricyanide solutions (Fe(CN)63−/4−, 2.5 mM, pH 7.4). (B) ECL intensity profiles of the luminol-Au NPs@PPy/GCE (curve a), anti-CEA-luminol-Au NPs@PPy/GCE (curve b), BSA/anti-CEA-luminol-Au NPs@PPy/GCE (curve c) and CEA/BSA/anti-CEA-luminol-Au NPs@PPy/GCE (curve d) measured in CBS (pH 10.4) containing 25 mM H2O2.

Mentions: Electrochemical impedance spectroscopy (EIS) was used to monitor the stepwise assembly of the immunosensor taking place in the presence of iron ferrocyanides (Fe(CN)63−/4−, 2.5 mM). It was an effective and convenient method to study the interfacial resistance of different modified electrodes without destruction by directly converting bioactivator into electrical signal3031. The EIS measurements were carried out in the frequency range from 0.1 to 100 kHz. The EIS curves of the GCE at different modification states were shown in Fig. 3A. In detail, there was a small semicircle domain on the bare electrode, which attributed to the diffusion limited electrochemical process. When the electrode was immobilized with anti-CEA-luminol-Au NPs@PPy (curve c), its diameter of the semicircle domain markedly increased compared with the electrode modified with luminol-Au NPs@PPy (curve b) due to the obstruction of anti-CEA for the electron transfer from the electrode to the solution. This phenomenon confirmed that the anti-CEA was bonded to luminol-Au NPs@PPy successfully. After BSA was dropped onto the electrode (curve d), the charge transfer resistance value increased sharply, which was attributed to the fact that the BSA attached onto Au NPs or PPy via gold-amino bonds or physical absorption resulting the conductive support and counteracting the interfacial electron transfer32. After successful capture of CEA, the diameter of the semicircle increased (curve e). The increased charge transfer resistance caused by that the antigen-antibody complex was generated on the electrode through specific reaction, which blocked the electron transfer33. The results were consistent with the fact that the electrode was modified as expected. Simultaneously, the corresponding ECL responses of different modified electrodes were investigated (Fig. 3B). As expected, the ECL intensity of electrodes was obviously decreased with stepwise fabrication. It further proved that the label-free ECL immunosensor was successfully fabricated.


Single-step cycle pulse operation of the label-free electrochemiluminescence immunosensor based on branched polypyrrole for carcinoembryonic antigen detection.

Zhu W, Wang Q, Ma H, Lv X, Wu D, Sun X, Du B, Wei Q - Sci Rep (2016)

(A) EIS of the electrode at different modification stages: (a) bare GCE, (b) luminol-Au NPs@PPy/GCE, (c) anti-CEA-luminol-Au NPs@PPy/GCE, (d) BSA/anti-CEA-luminol-Au NPs@PPy/GCE and (e) CEA/BSA/anti-CEA-luminol-Au NPs@PPy/GCE measured in ferricyanide solutions (Fe(CN)63−/4−, 2.5 mM, pH 7.4). (B) ECL intensity profiles of the luminol-Au NPs@PPy/GCE (curve a), anti-CEA-luminol-Au NPs@PPy/GCE (curve b), BSA/anti-CEA-luminol-Au NPs@PPy/GCE (curve c) and CEA/BSA/anti-CEA-luminol-Au NPs@PPy/GCE (curve d) measured in CBS (pH 10.4) containing 25 mM H2O2.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4835776&req=5

f3: (A) EIS of the electrode at different modification stages: (a) bare GCE, (b) luminol-Au NPs@PPy/GCE, (c) anti-CEA-luminol-Au NPs@PPy/GCE, (d) BSA/anti-CEA-luminol-Au NPs@PPy/GCE and (e) CEA/BSA/anti-CEA-luminol-Au NPs@PPy/GCE measured in ferricyanide solutions (Fe(CN)63−/4−, 2.5 mM, pH 7.4). (B) ECL intensity profiles of the luminol-Au NPs@PPy/GCE (curve a), anti-CEA-luminol-Au NPs@PPy/GCE (curve b), BSA/anti-CEA-luminol-Au NPs@PPy/GCE (curve c) and CEA/BSA/anti-CEA-luminol-Au NPs@PPy/GCE (curve d) measured in CBS (pH 10.4) containing 25 mM H2O2.
Mentions: Electrochemical impedance spectroscopy (EIS) was used to monitor the stepwise assembly of the immunosensor taking place in the presence of iron ferrocyanides (Fe(CN)63−/4−, 2.5 mM). It was an effective and convenient method to study the interfacial resistance of different modified electrodes without destruction by directly converting bioactivator into electrical signal3031. The EIS measurements were carried out in the frequency range from 0.1 to 100 kHz. The EIS curves of the GCE at different modification states were shown in Fig. 3A. In detail, there was a small semicircle domain on the bare electrode, which attributed to the diffusion limited electrochemical process. When the electrode was immobilized with anti-CEA-luminol-Au NPs@PPy (curve c), its diameter of the semicircle domain markedly increased compared with the electrode modified with luminol-Au NPs@PPy (curve b) due to the obstruction of anti-CEA for the electron transfer from the electrode to the solution. This phenomenon confirmed that the anti-CEA was bonded to luminol-Au NPs@PPy successfully. After BSA was dropped onto the electrode (curve d), the charge transfer resistance value increased sharply, which was attributed to the fact that the BSA attached onto Au NPs or PPy via gold-amino bonds or physical absorption resulting the conductive support and counteracting the interfacial electron transfer32. After successful capture of CEA, the diameter of the semicircle increased (curve e). The increased charge transfer resistance caused by that the antigen-antibody complex was generated on the electrode through specific reaction, which blocked the electron transfer33. The results were consistent with the fact that the electrode was modified as expected. Simultaneously, the corresponding ECL responses of different modified electrodes were investigated (Fig. 3B). As expected, the ECL intensity of electrodes was obviously decreased with stepwise fabrication. It further proved that the label-free ECL immunosensor was successfully fabricated.

Bottom Line: Moreover, 1-butylpyridinium tetrafluroborate ([BPy]BF4) were used to disperse luminol functional-Au NPs@polypyrrole nanocomposites, resulting in the film-formation of composites on the electrode, which could improve the stability of immunosensor.The proposed method presents good ECL response for the detection of CEA allowing a wide linear range from 0.01 pg/mL to 10 ng/mL and a limit of detection as low as 3 fg/mL.The immunosensor would be a promising tool in the early diagnosis of CEA due to its high sensitivity, simplicity and cost-effective.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Chemical Sensing &Analysis in Universities of Shandong, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, P.R. China.

ABSTRACT
A novel label-free electrochemiluminescence (ECL) immunosensor based on luminol functional-Au NPs@polypyrrole has been developed for the detection of carcinoembryonic antigen (CEA). In this work, polypyrrole prepared by chemical polymerization provided a large surface area to load amounts of gold nanoparticles (Au NPs). Au NPs could not only attach abundant luminol for the enhancement of ECL signal, but also provide a friendly microenvironment for the immobilization of antibodies. Moreover, 1-butylpyridinium tetrafluroborate ([BPy]BF4) were used to disperse luminol functional-Au NPs@polypyrrole nanocomposites, resulting in the film-formation of composites on the electrode, which could improve the stability of immunosensor. In particular, employment of single-step cycle pulse could limit the consecutive reaction between luminol and H2O2 efficiently, thus leading to stable and strong signals. The proposed method presents good ECL response for the detection of CEA allowing a wide linear range from 0.01 pg/mL to 10 ng/mL and a limit of detection as low as 3 fg/mL. The immunosensor would be a promising tool in the early diagnosis of CEA due to its high sensitivity, simplicity and cost-effective.

No MeSH data available.