Fabrication and electrochemical study of monodisperse and size controlled Prussian blue nanoparticles protected by biocompatible polymer

Monodisperse and size controlled Prussian blue (PB) nanoparticles have been synthesized using chitosan as protective matrix. The method depends on electrostatic interactions of Fe(CN)₆³⁻ ions with cationic chitosan macromolecules followed by the reaction with FeCl₂. The observation of transmission electron microscope (TEM) showed that the diameter of these monodisperse nanoparticles ranged from 5 to 20 nm with different chitosan contents. X-ray diffraction (XRD) analysis further identified a face-centered cubic structure of the nanoparticles. Investigations of optical properties of nanoparticles were also conducted with Fourier transform infrared (FT-IR) and Ultra violet/visible (UV-vis) spectroscopy. Moreover, cyclic voltammetry (CV) demonstrated that the chitosan-PB nanoparticles kept their intrinsic electrochemical properties and electrocatalytic activity towards hydrogen peroxide. This method represents a new route for preparing biocompatible Prussian blue nanoparticles that offers control over the size and protection against aggregation.     

3D Prussian blue/Pt decorated carbon nanofibers based screen-printed microchips for the ultrasensitive hydroquinone biosensing

Nowadays,water pollution has become more serious,greatly affecting human life and healthy.Electrochemical biosensor,a novel and rapid detection technique,plays an important role in the real-time and trace detection of water pollutants.However,the stability and sensitivity of electrochemical biosensors remain a great challenge for practical detections in real samples to the strong interferences derived from complex components and coagulation effects.In this work,we reported a novel three-dimensional architecture of Prussian blue nanoparticles (PBNPs)/ Pt nanoparticles (PtNPs) composite film,using 3D interweaved carbon nanofibers as a supporting matrix,for the construction of screen-printed microchips-based biosensor.PtNPs with diameters of～2.5 nm was highly dispersed on the carbon nanofibers (CNFs) to build a 3D skeleton nanostructure through a solvothermal reduction.Subsequently,uniform PBNPs were in-situ self-assembled on this skeleton to construct a 3D architecture of PB/Pt-CNF composite film.Due to the synergistic effects derived from this special feature,the as-prepared hydro-quinone (HQ) biosensor chips can synchronously promote both surface area and conductivity to greatly enhance the electrocatalysis from enzymatic reaction.This biosensor has exhibited a high sensitivity of 220.28 μA·L·mmol-1·cm-2 with an ultrawide linear range from 2.5μmol·L-1 to 1.45 mmol·L-1 at a low potential of 0.15 V,as well as the satisfactory reproducibility and usage stability.Besides,its accuracy was also verified in the assays of real water samples.It is highly expected that the 3D PB/Pt-CNF based screen-printed microchips will have wide applications in dynamic monitoring and early warning of ana-lytes in the various practical fields.     

Electrochemical sensing based on graphene oxide/Prussian blue hybrid film modified electrode

A novel graphene oxide (GO)/Prussian blue (PB) hybrid film was constructed by electropolymerizing Prussian blue onto the GO modified glassy carbon electrode, and its electrochemical behaviors were studied. Raman spectra were used to investigate the successful formation of the GO/PB hybrid film. Electrochemical experiments showed that the graphene oxide greatly enhanced electrochemical reactivity of the PB. Moreover, a much higher Prussian blue (PB) loading (6.388 × 10⁻⁸ mol cm⁻²) is obtained as compared to the bare glass carbon surface (3.204 × 10⁻⁹ mol cm⁻²). The GO/PB hybrid film modified electrode was used for the sensitive detection of hydrogen peroxide. The sensor exhibited a wide linearity range from 5.0 × 10⁻⁶ to 1.2 × 10⁻³ M with a detection limit of 1.22 × 10⁻⁷ M (S/N = 3), high sensitivity of 408.7 μA mM⁻¹ cm⁻² and good reproducibility. Furthermore, with glucose oxidase (GOD) as a model, the GO/PB/GOD/chitosan composite-modified electrode was also constructed.The resulting biosensor exhibited good amperometric response to glucose with linear range from 0.1 to 13.5 mM at 0.1 V, good reproducibility and detection limit of 3.43 × 10⁻⁷ M (S/N = 3). In addition, the biosensor presented high selectivity and long-term stability. Therefore, the PB/GO hybrid films-based modified electrode may hold great promise for electrochemical sensing and biosensing applications.     

Photoelectrocatalytic determination of NADH in a flow injection system with electropolymerized methylene blue

It was firstly described that a glassy carbon electrode electropolymerized with methylene blue shows an efficient photoelectrocatalytic activity towards NADH oxidation in a phosphate buffer solution (pH 7.0). In order to perform the photoelectrocatalytic determination of NADH in a flow injection analysis (FIA) system, a home-made flow electrochemical cell with a suitable transparent window for the irradiation of the electrode surface was constructed. The currents obtained from the photoamperometric measurements in the FIA system at optimum conditions (flow rate of carrier solution, 1.3 mL min⁻¹; transmission tubing length, 10 cm; injection volume, 100 μL; and constant applied potential, +150 mV vs. Ag/AgCl) were linearly dependent on the NADH concentration and linear calibration curves were obtained in the range of 1.0 × 10⁻⁷–2.0 × 10⁻⁴ M. The detection limit was found to be 4.0 × 10⁻⁸ M for photoamperometric determination of NADH.     

Micromolar determination of sulfur oxoanions and sulfide at a renewable sol-gel carbon ceramic electrode modified with nickel powder

The sol-gel technique was used to fabricate nickel powder carbon composite electrode (CCE). The nickel powder successfully used to deposit NiO_x thin film on conductive carbon ceramic electrode for large surface area catalytic application. Repetitive cycling in potential range −0.2 to 1.0 V was used to form of a thin nickel oxide film on the surface carbon composite electrode. The thin film exhibits an excellent electro-catalytic activity for oxidation of SO₃²⁻, S₂O₄²⁻, S₂O₃²⁻, S₄O₆²⁻ and S²⁻ in alkaline pH range 10-14. Optimum pH values for detection of all sulfur derivatives is 13 and catalytic rate constants are in range 2.4 × 10³-8.9 × 10³ M⁻¹ s⁻¹. The hydrodynamic amperometry at rotating modified CCE at constant potential versus reference electrode was used for detection of sulfur derivatives. Under optimized conditions the calibration plots are linear in the concentration range 10 μM-15 mM and detection limit 1.2-34 μM and 0.53-7.58 nA/μM (sensitivity) for electrode surface area 0.0314 cm². The nickel powder doped modified carbon ceramic electrode shows good reproducibility, a short response time (2.0 s), remarkable long term stability, less expense, simplicity of preparation, good chemical and mechanical stability, and especially good surface renewability by simple mechanical polishing and repetitive potential cycling. This sensor can be used into the design of a simple and cheap chromatographic amperometry detector for analysis of sulfur derivatives.     

A kinetic study of the electrocatalytic oxidation of reduced glutathione at Prussian blue film-modified electrode using rotating-disc electrode voltammetry

In this work a thorough study of the oxidation of reduced glutathione (GSH) by electro-generated Berlin Green (BG) at Prussian blue (PB) film-modified glassy carbon electrode (GCE) was attempted by employing cyclic voltammetry (CV) and rotating-disc electrode (RDE) techniques. It has been shown that oxidation of GSH occurs at the potential coinciding with that of Fe^II(CN)₆ to Fe^III(CN)₆ transformation in the PB film, where no oxidation signal is observed at a bare GCE. The kinetics of catalytic reaction was investigated using a rotating-disc electrode voltammetry. The results obtained for various thicknesses of film and GSH concentrations are explained using the theory of electrocatalytic reactions at chemically modified electrodes (Andrieux–Saveant model) and it was concluded that the reaction has a “surface” reaction mechanism in which a few monolayers at film/solution side engaged in the catalytic process. However, the “surface” reaction tends to a saturation limit with increasing GSH concentration was observed and the behavior has been explained by using Michealis–Menten inner sphere kinetics. Tafel plots for various concentrations of GSH have been drawn and the slope values of 95–110 mV/decade indicate that the first electron transfer is not rate limiting process. The reaction order with respect to GSH and H⁺ were calculated as 0.6 and −0.4, respectively.     

自组装普鲁士蓝膜修饰电极的制备及表征

通过静电自组装技术在Pt电极表面组装了不同层数的普鲁士蓝（PB）膜,得到了PB修饰的Pt电极。分别利用扫描电镜（SEM）和紫外-可见分光光度计（UV-Vis）表征膜的形貌及光学特性,并且采用循环伏安法（CV）测量膜修饰的Pt电极的循环伏安特性。结果表明：通过自组装技术可以制备出可控厚度的纳米尺度的PB膜修饰电极,膜的紫外吸收峰强度与组装层数符合线性关系,膜的组成同时含有可溶和不溶性PB,且循环伏安法所得到的峰电流正比于扫描速度的平方根以及PB的本体浓度,修饰电极具有好的电化学性能,可用于生物传感器。     

Amperometric glucose biosensor based on Prussian blue-multiwall carbon nanotubes composite and hollow PtCo nanochains

In this paper, a novel glucose biosensor was developed based on immobilizing glucose oxidase (GOD) on Prussian blue-multiwall carbon nanotubes (PB@MWNTs) composite and hollow PtCo (H-PtCo) nanochains modified electrode. The PB@MWNTs/H-PtCo membrane showed good biocompatibility, large surface-to-volume ratio and excellent electron-conductive ability. The successful fabrication of the PB@MWNTs composite synthesized with MWNTs as a template and Fe(III)-reducer were characterized by UV-vis absorption spectroscopy, Fourier transform infrared (FTIR) spectrometry and transmission electron microscopy (TEM). The hollow PtCo nanochains were also characterized by TEM and X-ray photoelectron spectroscopy (XPS). The response of the biosensor towards glucose under the optimized conditions, as investigated by chronoamperometry, is linear from 3.0 μM to 3.6 mM, with a low detection limit of 0.85 μM (S/N = 3) and a high sensitivity 21 mA M⁻¹ cm⁻². Moreover, the biosensor exhibits strong anti-interferent ability, good reproducibility and excellent stability.     

Mechanism investigation of Prussian blue electrochemically deposited from a solution containing single component of ferricyanide

Prussian white (a reduced state of Prussian blue) was electrochemically deposited on a polycrystalline Pt electrode from an acidic solution of ferricyanide. Electrochemical measurements showed that the formation of Prussian white on platinum electrode was a self-terminated process. A compacted PB film can be formed by using both potential scanning and potentiostatic methods as confirmed by AFM measurement. In situ FTIR measurements were carried out to explore the formation mechanism. The new band arising at 2075 cm⁻¹ is assigned to the characteristic absorbance of CN of Prussian white, while the band at 2104 cm⁻¹ is due to the absorbance of CN of Prussian blue. A possible mechanism of electrodeposition of Prussian white was discussed.     

Prussian blue nanoparticles potentiostatically electrodeposited on indium tin oxide/chitosan nanofibers electrode and their electrocatalysis towards hydrogen peroxide

Chitosan (CS) nanofibers were successfully used to modify indium tin oxide (ITO) electrode by electrospinning technique. Then, Prussian blue (PB) nanoparticles were electrodeposited on the CS nanofibers by potentiostatic technique in an acidic solution containing single ferricyanide. By this method, direct synthesis of PB nanoparticles on the nanofibers that were used for modifying electrode came true. Transmission electronic microscopy (TEM) showed that the average size of PB nanoparticles was about 50 nm. Selected-area electron diffraction (SAED) showed diffusive diffraction spots, indicating the mosaic structure of the PB nanoparticles on the CS nanofibers. X-ray powder diffraction (XRD) displayed the long-range disorder of CS nanofibers and demonstrated the formation of PB nanoparticles. Results of the scanning electron microscope (SEM) images indicated that the PB nanoparticles could be electrodeposited on the CS nanofibers. The amount of the PB nanoparticles on the CS nanofibers increased with increasing potential value of the electrodeposition. In addition, the cyclic voltammetric response displayed two characteristic redox couples of PB. The modified electrode exhibited electrocatalytic activity towards reduction of H₂O₂.     

Preparation of tungsten oxide nanoporous thin film at carbon ceramic electrode for electrocatalytic applications

The electrodeposition of nanoporous tungsten oxide (WO₃) on the surface of carbon ceramic electrode (CCE) was described. The morphology of the WO₃ modified electrode was characterized by scanning electron microscopy and X-ray diffraction. The modified electrode was utilized as an electrochemical hydrogen peroxide sensor in a low potential with a high sensitivity and selectivity. The role of supporting matrix on the sensitivity of modified electrode was studied. The detection limit of 0.26 μM (S/N = 3) and the sensitivity of 16.8 A M⁻¹ cm⁻² were compared with some other metal oxides hydrogen peroxide sensors. The modified electrode has exhibited good reproducibility, long-term stability and negligible interference of some inorganic and biological compounds.     

Preparation of a sol-gel-derived carbon nanotube ceramic electrode by microwave irradiation and its application for the determination of adenine and guanine

In this study, microwave irradiation was used for the fast preparation (min) of a sol-gel-derived carbon nanotube ceramic electrode (MW-CNCE). For confirmation of the preparation of the ceramic by MW irradiation, Fourier transform infrared, X-ray diffraction spectra and scanning electron microscopy images of the produced ceramic were compared with those of conventional ceramic (which is produced by drying the ceramic in air for 48 h). The electrochemical behavior of MW-CNCE in nicotinamide adenine dinucleotide, l-cysteine, adenine and guanine was compared with that of a conventional sol-gel-derived carbon nanotube ceramic electrode (CNCE). In all systems, similar peak potentials and lower background currents were obtained with respect to CNCE. Finally, the MW-CNCE was used for the simultaneous determination of adenine and guanine using differential pulse voltammetry. The linear ranges of 0.1-10 and 0.1-20 μM were obtained for adenine and guanine, respectively. These results are comparable with some modified electrodes that have recently been reported for the determination of adenine and guanine, with the advantage that the proposed electrode did not contain modifier. In addition, the proposed electrode was successfully used for the oxidation of adenine and guanine in DNA, and the detection limit for this measurement was 0.05 μg mL⁻¹ DNA.     

Multilayer structured amperometric immunosensor based on gold nanoparticles and Prussian blue nanoparticles/nanocomposite functionalized interface

In this paper, a novel strategy for the fabrication of sensitive reagentless amperometric immunosensor was proposed. Firstly, Prussian blue nanoparticles (PBNPs) as redox probe were immobilized on three dimensional structured membrane of the gold colloidal nanoparticles (AuNPs) doped chitosan-multiwall carbon nanotubes (CS-MWNTs) homogeneous composite (CS-MWNTs-AuNPs) by electrostatic interactions between the negatively charged PBNPs and the positively charged amino groups of CS and strong binding interaction between GNPs and nitrile group (-CN) of PBNPs. Subsequently, the gold nanoparticles (GNPs) were electrodeposited on the surface of the composite by electrochemical reduction of gold chloride tetrahydrate (HAuCl₄) to immobilize antibody biomolecules (anti-CEA) and avoid the leakage of PBNPs. The stepwise assembly process was characterized by means of cyclic voltammetry (CV) and electrochemical impendance spectroscopy (EIS). Furthermore, the morphology of the prepared nanomaterials was researched by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Under the optimized conditions, the decrease of CVs current of determination CEA was proportional to concentration ranges from 0.3 to 120 ng/mL with a detection limit of 0.1 ng/mL at a signal-to-noise of 3. Moreover, the proposed immunosensor exhibited good accuracy, high sensitivity and stability.     

The role of vacancies in the hydrogen storage properties of Prussian blue analogues

The porosity and hydrogen storage properties of the dehydrated Prussian blue type solids Ga[Co(CN)₆], Fe₄[Fe(CN)₆]₃, M₂[Fe(CN)₆] (M = Mn, Co, Ni, Cu), and Co₃[Co(CN)₅]₂ are reported and compared to those of M₃[Co(CN)₆]₂ (M = Mn, Fe, Co, Ni, Cu, Zn). Nitrogen sorption measurements suggest partial framework collapse for M₂[Fe(CN)₆] (M = Co, Ni) and Co₃[Co(CN)₅]₂, and complete collapse for Mn₂[Fe(CN)₆]. Hydrogen sorption isotherms measured at 77 K reveal a correlation between uptake capacity and the concentration of framework vacancies, with Langmuir–Freundlich fits predicting saturation values of 1.4 wt.% for Ga[Co(CN)₆], 1.6 wt.% for Fe₄[Fe(CN)₆]₃, 2.1 wt.% for Cu₃[Co(CN)₆]₂, and 2.3 wt.% for Cu₂[Fe(CN)₆]. Enthalpies of H₂ adsorption were calculated from isotherms measured at 77 and 87 K. Importantly, the values obtained for compounds with framework vacancies are not significantly greater than for the fully-occupied framework of Ga[Co(CN)₆] (6.3–6.9 kJ/mol). This suggests that the exposed metal coordination sites in these materials do not dominate the hydrogen binding interaction.     

Low potential detection of glucose at carbon nanotube modified glassy carbon electrode with electropolymerized poly(toluidine blue O) film

A mediator glucose biosensor has been constructed by immobilizing glucose oxidase at electropolymerized poly(toluidine blue O) film on carbon nanotube modified glass carbon electrode. The toluidine blue O moieties served as redox mediators for enzymatic glucose oxidation and as polymeric network to maintain the biosensor activity. Great enhancement in current response was observed for the glucose biosensor. The detection potential could be decreased to −0.1 V (versus Ag|AgCl), where common interferences such as ascorbic acid, uric acid and acetamidophenol were not oxidized to cause interferences. The amperometric glucose biosensor offered a sensitivity of 14.5 mA M⁻¹ cm⁻² for the linear range of 1-7 mM.     

Electrochemical behavior of an indenedione derivative electrodeposited on a renewable sol-gel derived carbon ceramic electrode modified with multi-wall carbon nanotubes: Application for electrocatalytic determination of hydrazine

A novel modified carbon ceramic electrode (CCE) containing multi-wall carbon nanotubes (MWCNTs) was fabricated by a sol-gel technique. The prepared MWCNT-CCE was modified by the electrodeposition of an indenedione derivative. The indenedione modified MWCNT-CCE (IMWCNT-CCE) shows one pair of peaks with surface confined characteristics. According to the theoretical model of Laviron, estimations were made in different pHs of the surface charge transfer rate constant, k_s, and the charge transfer coefficient, α, for electron transfer between the indenedione derivative and MWCNT-CCE. The modified electrode shows a highly catalytic activity toward hydrazine electrooxidation at a wide pH range (5-9). The kinetic parameters such as the electron transfer coefficient, α, the heterogeneous rate constant, k′, and the exchange current of hydrazine at the IMWCNT-CCE were calculated as 0.29 ± 0.01, 2.7(±0.3) × 10⁻³ cm s⁻¹ and 0.17 ± 0.03 μA, respectively. Also, the modified electrode shows an excellent analytical performance for voltammetric determination of hydrazine. Differential pulse voltammetry (DPV) exhibits two linear dynamic ranges, 0.6-8.0 μM and 8.0-100.0 μM, and a lower detection limit of 0.29 μM for hydrazine. Finally, the practical analytical utility is illustrated by differential pulse voltammetric determination of hydrazine in auxiliary cooling water at IMWCNT-CCE and the accuracy of the results is verified in comparison with those obtained from the standard ASTM method.     

Photoinducedly electrochemical preparation of Prussian blue film and electrochemical modification of the film with cetyltrimethylammonium cation

This work presents a photoinducedly electrochemical preparation of Prussian blue from a single sodium nitroprusside and insertion of cetyltrimethylammonium cations into Prussian blue as counter ions. The product of photoinducedly electrochemical reactions has a couple of voltammetric peaks at E° = 0.266 V in 0.2 mol l⁻¹ KCl solution, the measurements of X-ray powder diffraction and FT-IR spectroscopy show that it is Prussian blue (PB). The formation mechanism of a pre-photochemical reaction and subsequent electrochemical reaction is suggested. The cyclic voltammetric treatment of the freshly as-prepared PB film in 1.0 mmol l⁻¹ cetyltrimethylammonium (CTA) bromide solution leads to the insertion of cetyltrimethylammonium cations into the channels of Prussian blue, which substitutes for potassium ions as counter ions in Prussian blue. The Prussian blue containing CTA counter ions shows two couples of voltammetric peaks at E° = −0.106 V and E° = 0.249 V in 0.2 mol l⁻¹ KCl solution containing 1.0 mmol l⁻¹ cetyltrimethylammonium bromide. Compared with the electrochemical behaviors of KFeFe(CN)₆ in 0.1 mol l⁻¹ KOH alkali solution, CTAFeFe(CN)₆ shows relatively durable voltammetric currents due to the hydrophobic effects of cetyltrimethylammonium. The diffusion coefficients for CTA and potassium cations were estimated to be D_CTA 1.25 × 10⁻¹² cm² s⁻¹, D_K 2.59 × 10⁻¹² cm² s⁻¹, respectively. The peak current of electro-catalytic oxidization on hydrogen peroxide showed a linear dependence from 6.59 × 10⁻⁶ to 2.20 × 10⁻⁴ mol l⁻¹ with R = 0.99947 (n = 8). The linear regression equation was I_p (mA) = 0.82949 + 0.00594C (μmol l⁻¹) with errors of ±7.92833 × 10⁻⁵ for the slope and ±0.01085 for the intercept with the detection limit of 1.46 × 10⁻⁶ mol l⁻¹. Thus, it is expected to find its application in neutral or weak alkali medium for biosensors.     

Enhanced degradation of reactive dyes using a novel carbon ceramic electrode based on copper nanoparticles and multiwall carbon nanotubes

A novel carbon ceramic electrode consisting of CuNPs and MWCNT was developed to treat reactive orange 84 (RO84) wastewater using ultrasound-assisted electrochemical degradation. The proposed electrode generated more hydroxyl radicals than non-nanoparticle electrodes did. In addition, a new electrochemical sensor was applied to determine residue RO84 in an aqueous medium during discoloration. This sensor is based on a glassy carbon electrode modified with gold nanourchins and graphene oxide and can detect RO84 concentration in the range of 1.0-1200 μmol·L^-1 with the detection limit of 0.03 μmol·L^-1. The degradation effects of the modified electrode on RO84 were evaluated systematically with different initial pH values, time durations, and amounts of CuNPs and MWCNT. The results suggested that the removal efficiency of RO84 was approximately 83% after 120 min of electrolysis in a phosphate buffer with pH 8.0 using a carbon ceramic electrode made with 4.0 wt% CuNPs and 4.0 wt% MWCNT. The possible mechanism of RO84 degradation was monitored by gas chromatography-mass spectrometry, and degradation pathways were proposed.     

Electrocatalytic oxidation of methanol and ethanol at carbon ceramic electrode modified with platinum nanoparticles

The use of carbon ceramic electrode (CCE) modified with platinum particles was studied for the electrocatalytic oxidation of methanol and ethanol by cyclic voltammetry and chronoamperometry. After preparation of a carbon ceramic as an electrode matrix by sol–gel technique, its surface was potentiostatically coated with Pt nanoparticles at −0.2 V vs. SCE in an aqueous solution of 0.1 M H₂SO₄ containing 0.002 M H₂PtCl₆. The electrocatalyst was characterized by XRD, SEM and cyclic voltammetry. The effective parameters on electrocatalytic oxidation of the alcohols, i.e. the amount Pt loadings, medium temperature and working potential limit in anodic direction were investigated and the results were discussed. This modified electrode showed an enhanced current density over the other Pt-modified electrodes making it more attractive for fuel cell applications.     

Electrochemical immunosensor for human chorionic gonadotropin based on horseradish peroxidase–functionalized Prussian blue–carbon nanotubes/gold nanocomposites as labels for signal amplification

A new strategy for the sensitive detection of biomarker using Prussian blue–carbon nanotubes/gold nanocomposites (GNPs–PB–CNTs) as labels and horseradish peroxidase (HRP) as an enhancer is presented herein. Chitosan hydrogel and TiO₂ nanocomposites were first coated onto a glassy carbon electrode (GCE) surface, which provided a biocompatible interface with abundant –NH₂ groups for the immobilization of primary antibodies (Ab₁). The detectable signal was recorded and amplified based on a sandwich-type immunoassay by the employment of HRP-labeled secondary antibodies (HRP-Ab₂) and GNPs–PB–CNTs bioconjugates according to the electrocatalytic reduction of H₂O₂ by bound HRP in the presence of PB. Using human chorionic gonadotropin (HCG) as a model analyte, experimental results showed that the prepared HRP-Ab₂–GNPs–PB–CNTs bioconjugates exhibited satisfactory redox activity and high efficiency of enzyme catalysis. Under optimized conditions, the immunosensor showed a low detection limit of 0.023 mIU/mL HCG, with a linear range from 0.05 to 150 mIU/mL. The proposed method exhibited high sensitivity, acceptable stability and reproducibility, and could be extended to detect other protein targets.