Silver nanoparticle-functionalized polydopamine nanotubes for highly sensitive nanocomposite electrode sensors

Journal Pre-proof Silver nanoparticle-functionalized polydopamine nanotubes for highly sensitive nanocomposite electrode sensors

Lingfeng Gan, Chao Chen, Peng Qin, Yibing Wang, Ping Wang PII:

S1572-6657(20)30144-2

DOI:

https://doi.org/10.1016/j.jelechem.2020.113961

Reference:

JEAC 113961

To appear in:

Journal of Electroanalytical Chemistry

Received date:

28 September 2019

Revised date:

16 January 2020

Accepted date:

13 February 2020

Please cite this article as: L. Gan, C. Chen, P. Qin, et al., Silver nanoparticle-functionalized polydopamine nanotubes for highly sensitive nanocomposite electrode sensors, Journal of Electroanalytical Chemistry(2018), https://doi.org/10.1016/j.jelechem.2020.113961

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© 2018 Published by Elsevier.

Journal Pre-proof

Silver Nanoparticle-Functionalized Polydopamine Nanotubes for Highly Sensitive Nanocomposite Electrode Sensors Lingfeng Gan1, Chao Chen1, Peng Qin1, Yibing Wang1,*, Ping Wang2,* 1 China State Key laboratory of Bioreactor Engineering, Biomedical Nanotechnology Center, School of Biotechnology, East China University of Science and Technology, Shanghai 200237, P. R. China. 2 Department of Bioproducts and Biosystems Engineering, University of Minnesota, St Paul, MN 55108, USA

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*Corresponding author, E-mail: [email protected], [email protected]

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Abstract:

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Multi wall carbon nanotubes (MWCNTs) are used in construction of nanocomposite electrode for many sensors. However, the chemical stability of MWCNTs simplicities difficulties for surface

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modification and further functionalization. Polydopamine nanotubes (PDA-NTs) possess

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nitrogen-doped polycyclic aromatic hydrocarbons sidewalls, which not only reassemble the structure and the electrochemical properties of carbon nanotubes, but also afford active surfaces for further

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functionalization. This work examines the fabrication of PDA-NTs with silver nanoparticles (AgNPs) for construction of nanocomposite electrodes for highly sensitive chemical analysis. The prepared

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PDA-NTs share the similar backbone structure like MWCNTs as analysis by Raman spectroscopy. Grown AgNPs significant enhanced Raman peak intensity because of the surface enhancement of Raman scattering of AgNPs. In a test with hydrogen peroxide, Ag@PDA-NTs modified electrode showed an LDR of 5-200 μM and LOD of 0.68 μM, almost ten time lower than reported PDA and AgNPs modified electrode (LOD=6.5 μM). It also owns good reproducibility, long-term stability and interfering effect against GLU, UA and DA. AgNPs can also grow more easily on PDA-NTs than on MWCNTs at the same AgNO3 concentration and possess much better dispersivity at the same time. It appears that PDA supported nano fabrication is versatile and promising for development of high performance electrochemical sensors. Keywords: polydopamine nanotubes, hydrogen peroxide, electrochemical, silver nanoparticles, non-enzyme sensor

Journal Pre-proof 1. Introduction

Due to the specific orientation of hexagons of carbon atoms, multi wall carbon nanotubes (MWCNTs) have highly sensitive electronic properties that are desired for construction of nanocomposite electrodes for many applications including sensors[1]. However, the chemical stability and poor dispersivity of MWCNTs also implicates difficulties for surface modification and further functionalization[2]. Therefore, nanomaterials that offer mechanical, structural and morphology properties similar to MWCNTs, but offer much more versatile functionalization potentials can be

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greatly promising. In this regard, polydopamine (PDA) nanotubes that possess nitrogen-doped

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polycyclic aromatic hydrocarbons structure and better dispersivity have been explored as an

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emerging class of materials[3,4].

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PDA, a mussel-inspired polymer, having the ability to adhere on nearly any substrates by simply

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dipping dopamine solution the substrate, has been shown recently[5,6]. Because of their biocompatibility and unique optoelectronic properties, PDA has been examined for a broad range of

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applications in pollution treatment, coating material synthesis, drug release and sensors[7-11]. In particular, various PDA capsules have been prepared through sacrificial templates using silica,

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CaCO3, ZnO or polymer microparticles, and soft templates like emulsion[12-16]. Several kinds of structures of PDA including PDA nanotubes were synthesized by above methods. In addition, the chemical structure of PDA allows it readily reacts with many functional groups such as catechol, imine and amine. Such covalent modifications are greatly valuable for development of functionalized materials with desired component and properties[17]. Due to the molecular structures, reacted activity, electronic properties and biocompatibility, PDA was used as the spacer layer to design modified electrodes. Both of them may share the same high specific surface area and conductive sidewalls. Beside these basic structural properties, for a high sensitive chemical sensor, the sensitivity and quantity of response units are the most significant parts in design of electrode.

Enzyme often be used as response unit of electrochemical sensor. Enzyme based electrochemical sensors have been applied for several years on account of their catalytic capability. But due to the disadvantage of enzymes like strict environment requirements, stability, repeatability and

Journal Pre-proof complicated bonding manipulation, it still has some difficulty and challenges for industry application[18]. Thus, the development of non-enzyme electrochemical sensor with sensitive and efficient sensing performance based on nanomaterials has become a hot topic. Nanoparticles with different shape show catalytic activity compared with enzyme, which have been widely used in numbers of no-enzyme biosensors, such as gold nanoparticles and silver nanoparticles[19,20]. Because of the high reactive functional groups, nanoparticles functionalized PDA nanotubes may be a strategy to enrich nanoparticle with catalytic activity, resulting high surface area and activity of modified electrode. With such electrode, numbers of chemicals have potential to be detect by

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forming different nanoparticles on PDA nanotubes.

Hydrogen peroxide, an important intermediate to be detect in biosensor, plays a great role in

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physiology, aging and disease in living organisms[21]. Due to its significant function in both

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biological systems and practical applications, the efficient detection of H2O2 becomes an important

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topic recently. Electrochemical detection possesses the advantage of simple, celerity, sensitivity and cost saving. Therefore, it develops as a vital direction for H2O2 detection. Noble metal nanoparticles

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like silver nanoparticles (AgNPs) have size-related electronic/optical properties, extraordinary conductivity, large surface-to-volume ratio, and have been extensively employed for developing

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novel electrochemical sensors for H2O2 detection[22,23]. For example, Han et al. developed a H2O2 sensor by synthesizing a sandwich structure nanocomposite of Ag nanoparticles supported on MnO2 modified multiwall carbon nanotubes[24]. Lin et al. fabricated as H2O2 sensor based on silver nanoparticles, carbon nanotubes and chitosan film[25]. Jeon et al. constructed H2O2 sensors based on AgNPs which were readily synthesized in TiO2/PVA ultrathin films[26]. In summarize, electrode with Ag and large specific surface area is benefit for the H2O2 electrochemical detection.

Due to the native reductive feature of the PDA layer, silver ions in contact with PDA can be reduced into AgNPs. While MWCNTs should be carboxylated first and then using acitric acid as the reductant. In this study, we fabricate PDA-NTs by in situ reduction of Ag to prepare Ag@PDA-NTs, which provides potential for substitute electrode material MWCNTs and application for H2O2 detection (Schemes 1). The electrocatalytic behavior of Ag@PDA-NTs toward the electrochemical reaction of H2O2 were studied via cyclic voltammetry and amperometric response. The

Journal Pre-proof reproducibility and stability of the electrode was characterized.

2. Experiments 2.1 Materials Dopamine hydrochloride (DA) was purchased from Sangon (Shanghai, China). Hydrogen peroxide (H2O2) was purchased from Sinopharm (Shanghai, China). Curcumin was purchased from SCR (Shanghai, China). Ethanol and acetone were purchased form general-geagent (Shanghai, China). Ammonia, AgNO3 and PB buffer were purchased form Lingfeng (Shanghai, China). Glucose

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(GLU) and uric acid (UA) were purchased form BBI (Shanghai China). Nitrogen was purchased

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from Shenzhong (Shanghai, China). Multi wall carbon nanotube was purchased from XFNANO (Hangzhou, China). Ascorbic acid was purchased from Lingfeng (Shanghai, China). All reagents

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were of analytical grade and were used without further purification and all solutions were prepared

2.2Procedures

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2.2.1 Synthesis of PDA-NTs

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with deionized water.

In this experiment, 100 mg of curcumin and 500 mg of dopamine were dispersed in 100 mL of

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ethanol/acetone mixed solution (v/v 1:1) and then exchange the solvent by adding 400 mL water to induce the precipitation of curcumin crystals because of the insoluble of curcumin in water. After completing the precipitation of curcumin crystals, 3 mL Tris-HCl buffer solution (1.5 M, pH 8.8) was added to maintain the buffer concentration at 9 mM. The solution was stirred tenderly for 24 h and the color gradually turned into black. After that the sediment (PDA@curcumin) was isolated from the solution and rinsed by fresh water for three times. The sedimentation can be collected by centrifugation. Then PDA@curcumin was dispersed in ethanol to dissolve curcumin crystal template inside PDA nanotubes and the pure PDA nanotubes were obtained[27].

2.2.2 Synthesis of Ag@PDA-NTs and Ag@MWCNTs A silver ammonia solution was prepared by adding ammonia into AgNO3 solution until the solution became clear and the final AgNO3 concentration was 2, 4, 6, 10 mg/mL respectively. The PDA-NTs were put into the silver ammonia solution and dispersed by ultrasound for 5 min and then

Journal Pre-proof the reaction was conducted for 8h under stirring at 80°C. The Ag@PDA-NTs were washed with deionized water, centrifuged and dried in vacuum oven at 40°C until constant weight[28]. Ag@MWCNTs were synthetized in AgNO3 solution. The AgNO3 solution was added into the carboxylic MWCNTs solutions and the final AgNO3 concentration was 10 mg/mL. The mixture was dispersed by ultrasound for 30 min and then acitric acid was added into the mixture and stirred for 12h. The Ag@MWCNTs were also washed with deionized water, centrifuged and dried in vacuum oven[29, 30].

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2.2.3 Characterization of Ag@PDA-NTs and Ag@MWCNTs

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The TEM graphic of Ag@PDA-NTs and Ag@MWCNTs were observed by high resolution transmission electron microscopy (HR-TEM) (JEOL JEM-2100). The SEM graphic of

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Ag@PDA-NTs and Ag@MWCNTs were observed by S-3400N. Raman scattering measurements

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were performed at room temperature on a Raman system (Renishaw InVia-Reflex). GC electrode,

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grid and quartz were used as the substrate for electrochemical characterization, HR-TEM imaging and Raman spectrum, respectively. Raman spectra were measured by a Renishaw Iuvia Reflex

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Raman Spectrometer (Renishaw Apply Innovation, England).

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2.2.4 Preparation of the Ag@PDA-NTs modified electrode GCE was first polished by 0.3 μm alumina slurry and sonicated in deionized water and ethanol for 10 min respectively. Then the GCE was dried in the dryer at 60°C for 10 min. Finally the modified GCE was prepared by dripping Ag@PDA-NTs solution which is suspended in the ethanol at the concentration of 1 mg/mL and then dried in dryer.

2.3 Electrochemical measurements 2.3.1 Apparatus Electrochemical measurements were conducted on a CHI 760D electrochemical analyzer (Shanghai CH Instruments, China) and data were analyzed by the matched CHI software. A typical three-electrode system which including a modified GCE as the working electrode, a platinum electrode as the counter electrode and a silver chloride electrode as the reference was used.

Journal Pre-proof 2.3.2 Cyclic Voltammetry measurements Cyclic voltammetry (CV) of Ag@PDA-NTs was conducted in 0.1 M PB (pH 7.0) in the presence of H2O2 (Fig. 5). Different concentration of H2O2 from 0 to 6 mM and different scan rate from 10 to 300 mV·s-1 were respectively conducted at the potential range from -0.8 to 0 V. Before the CV, nitrogen was bubbled through the reaction solution for 20 min to remove oxygen.

2.3.3 Amperometric response Amperometric response of Ag@PDA-NTs was conducted in 0.1 M PB (pH7.0) with applied

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potential of -0.4 V. H2O2 was successively injected into the solution (Fig. 6a). The wider range of

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H2O2 current peak was measured from 0.001 to 5 mM (Fig. 6b). Before the test, nitrogen was

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bubbled through the solution for 20 min.

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2.3.4 Anti-interference

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Interfering effect was tested by added Glucose (GLU), dopamine (DA), uric acid (UA) into the reaction solution in 0.1 M PB buffer (pH 7.0) and the applied potential was -0.4 V (Fig. 7). Nitrogen

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was also injected through the solution for 20 min to remove dissolved oxygen.

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2.3.5 The reproducibility and stability

The reproducibility test was conducted for 10 times for the same modified electrode and the electrode was preserved in refrigerator for 30 days for the stability test.

3. Results and discussion

3.1 Characterization of Ag@PDA-NTs and Ag@MWCNTs PDA and Ag complex composite electrode was prepared using an in situ growth of AgNPs on PDA-NTs. PDA-NTs were pre-constructed with curcumin crystals as templates, which were then contacted with AgNO3 solution for growth of AgNPs on surface of the PDA-NTs aromatic residue groups function as the nucleation sites. To prepare Ag@MWCNTs, AgNPs were grown on the carboxyl group on MWCNTs surface. Fig. 1 shows SEM image of Ag@PDA-NTs and Ag@MWCNTs and TEM images of obtained Ag@PDA-NTs. As observed in Fig. 1a, PDA nanotubes prepared by this procedure have uniform size (diameter 500 nm), surface attached AgNPs

Journal Pre-proof shows up around 40 nm. TEM images (Fig. 1b), further indicated that the thickness of the wall of PDA-NT is about 40 nm as indicated by yellow line and the diameter of the nanotube is around 400 nm as indicated by red double arrow line segment. AgNPs produced through this procedure showed certain variation in terms of shapes and sizes, yet the formation of Ag (111) crystal lattice could be identified evidently in the Ag nanoparticles. As shown in Fig. 1c and Fig. 1d, interplanar crystal spacing is about 0.236 nm, which matches the theoretical data of the interplanar crystal spacing of Ag (111). In Fig. S1 and S2, with the same AgNO3 concentration, on the surface of Ag@MWCNTs, AgNPs is obviously much less than that on Ag@PDA-NTs. The AgNPs growing by PDA-NTs’ own

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reducibility seems much more effective and sturdier than AgNPs growing on MWCNTs. XRD (Fig.

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S3) of Ag@PDA-NTs and Ag@MWCNTs can also prove the result that there are more AgNPs and active Ag (111) on PDA-NTs. Despite that, from Fig. 2, Ag@PDA-NTs has obviously better

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dispersivity than Ag@MWCNTs in alcohol, which will be more beneficial for electrode preparation.

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As the chemical structure of electrode material is critical for its electrical properties, although dopamine is organic small molecule, after polymerization, PDA-NTs own the similar chemical

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structure with MWCNTs for electrode material. Chemical structural characterization of obtained Ag@PDA-NTs was further conducted. Fig. 3 presented Raman spectra of PDA-NTs, Ag@PDA-NTs,

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MWCNTs and Ag@MWCNTs. The similar feature of Raman spectrum between PDA-NTs and MWCNTs may shows the similar chemical structure for electrode material. The obtained PDA-NTs and Ag@PDA-NTs samples showed broad and strong peaks at 1300-1600 cm-1 (Fig. 3a). The Raman spectra of PDA-NTs and Ag@PDA-NTs are similar to the spectrum of MWCNTs which has D band around at 1346 cm-1 and G band around 1579 cm-1 (Fig. 3b). As well as carbon nanotube, the peak 1398 cm-1 and peak 1586 cm-1 in Raman spectrum of PDA-NTs can belong to D band and G band, respectively. The peak around 1398 cm-1 is aromatic ν(C-N) stretching mixed with indole ring stretching and another peak around 1586 cm-1 is appointed to ν(C=C) aromatic coupled with pyrrole ring stretching vibration or indole ring vibration. The intensity ratio (ID/IG) indicates the disordering and defect density of surface structures of carbon materials and can be used to characterize the functionalization of carbon nanotube[31]. After silver reduced on the catechol group of PDA-NTs, the stretching of ν(C=C) (D band) was restricted, and the restriction to aromatic ν(C-N) was relatively less. Therefore, the intensity ratio (ID/IG) can also indicate the functionalization of

Journal Pre-proof PDA-NTs by AgNPs. Intensity ratio (ID/IG) of PDA-NTs is lower than Ag@PDA-NTs’ and this can reflect AgNPs affected the surface structure of PDA-NTs. Further, peak intensity of Ag@PDA-NTs is nearly times that of PDA-NTs’ and this can considered as the surface enhancement of Raman scattering of AgNPs, which also indicate the effective reduction of silver on the PDA-NTs surface. While this phenomenon cannot be observed in the Raman of MWCNTs and Ag@MWCNTs (Fig. 3b). This is because AgNPs on MWCNTs is much less and this agrees with the TEM and EDS result (Fig. S1 and S2). There is no obvious red or blue shift was found indicating after reduction of silver no effluence on the parallel direction of aromatic ring, which may be important for the conductivity of

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PDA-NTs.

3.2 Electrochemical characterization

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As indicated in SEM image, numerous Ag@PDA-NTs can deposit on the surface of carbon

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material, thus GCE modified with Ag@PDA-NTs could have numerous AgNPs with catalysis

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activity contributed to electrochemical sensor toward H2O2. CVs of bare GCE, PDA-NTs/GCE and Ag@PDA-NTs/GCE are shown in Fig. 4a in the presence of 1.0 mM H2O2 respectively. It can be

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seen that the electrochemical responses of GCE and PDA-NTs/GCE electrodes are negligible, which indicates the PDA-NTs/GCE has no catalytic activity to H2O2. The blue curve in Fig. 4a shows the

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electrochemical behaviors of the Ag@PDA-NTs/GCE in 1.0 mM H2O2. Obvious increase at -0.4 V in the reduction current indicates the electrode can expeditiously catalyze H2O2and mostly results from the AgNPs on the electrocatalyic reduction of H2O2.

The effect of amount of AgNPs of Ag@PDA-NTs on sensor responses was investigated. AgNO3 solutions of different concentrations were dropped into PDA-NTs solution at the preparation of [email protected] shown in the Fig. 4b, the catalytic current at -0.4 V is increased with the increasing of concentration of the silver ion in the reaction. The increase of the current is considered as the enhancement of electrocatalysis with more AgNPs on PDA-NTs. These results show that the Ag@PDA-NTs/GCE with 10 mg/mL Ag possesses the relatively best catalytic ability to H2O2 reduction among these electrodes. Higher concentration of silver ion increased amount and diameter size of AgNPs on the PDA-NTs. It can be found that the potential of peak of Ag@PDA-NTs of 2 mg/mL is at -0.6 V, but not -0.4V of 10 mg/mL. The reason is the distinct H2O2 catalytic mechanism

Journal Pre-proof on the different size of AgNPs. Because-0.6 V is the reduction peak of O2 and -0.4 V is the direct reduction peak of H2O2, to remove interference and obtain high catalytic active we select 10 mg/mL as the optimum AgNPs amount to prepare the sensor.

3.3 Evaluation of the sensor Fig. 5a shows the CVs of Ag@PDA-NTs/GCE in the presence of H2O2 with different concentrations in 0.1 M PB buffer (pH 7.0) at the scan rate of 100 mV·s-1. No obvious peak was found when no H2O2was added into the system. The reduction peak appeared when 2 mM H2O2was

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introduced into the solution. This indicated the Ag@PDA-NTs/GCE have eminent electrocatalytic

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activity towards H2O2 and peak current gradually increases with the increment of H2O2 (0, 2, 4, 6 mM from the bottom). In addition, different scan rates were used for the investigation of the

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electrocatalytic behavior of the Ag@PDA-NTs/GCE towards H2O2 (Fig. 5b). When the scan rate

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increases from 10 mV·s-1 to 300 mV·s-1, the peak current also increased. The peak current was in a

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linear relationship within the range of scan rate from 10 to 300 mV·s-1 indicating the process is diffusion-controlled. The interspace between Ag@PDA-NTs on the modified electrode was

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image (Fig. 1a).

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important for diffusion, which originates form interleaved stacking of PDA-NTs as shown in SEM

3.4 Amperometric response and calibration curve Fig. 6 shows the amperometric response of Ag@PDA-NTs/GCE with continuous addition of H2O2 into 0.1 M PB buffer (pH 7.0) at potential of -0.4 V. As H2O2was injected into the solution and stirred at 200 rpm, the Ag@PDA-NTs/GCE responded rapidly and achieved steady-current state in less than 5s (Fig. 6a). From 5 μM to 200 μM of the H2O2 concentration, reduction currents showed linear response (Ip(μA)=1.666+0.0393cH2O2(μM), R = 0.9910) with a detection limit of 0.68 μM estimated at S/N = 3 (Fig. 6b). Comparison of the Ag@PDA-NTs/GCE with other H2O2 sensors shows in Table. 1 in terms of linear detection range (LDR), limit of detection (LOD) and response time. From the table it can be found that the Ag@PDA-NTs/GCE electrode could provide comparable and even better detection performance, especially the lower LOD applied potential than those reported recently[32-38]. Compared to construction of polydopamine/silver nanoparticles multilayer film for H2O2 detection, our modified electrode has the lower LOD and we consider it is

Journal Pre-proof because PDA-NTs has larger specific surface area and better electron transfer ability due to its tube construction. In addition, the LOD of Ag@PDA-NTs/GCE electrode is comparable with AgNPs-MWCNTs/Au[35], although the LDR is smaller. The lower LOD of Ag@PDA-NTs/GCE compared to the other sensors is maybe because of the analogous electrochemical property of MWCNTs, which needed to be researched and certify in the further work.

Table. 1

LDR (μM)

LOD (μM)

(PDA/AgNPs)2/GCE [32]

50-1750

6.5

Ag/Cu2O nanoparticles/ITO [33]

30-1000

Ag NW array [34]

100-3100

AgNPs-MWCNTs/Au [35]

50-17,000

Ag NPs-CNT/Au [36]

50-500

Ag-DNA NPs/GCE [37]

2-2500

0.6

Ag-UTPNSs/GCE [38]

100-90,000

0.57

Ag@PDA-NTs/GCE (our work)

0.68

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Electrode

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Comparison of the performances of various H2O2 sensors.

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0.1

29.2

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0.5

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5-200

1.6

3.5 Reproducibility, stability and interfering effect The reproducibility was estimated by the current response to the 0.1 mM H2O2 (0.1 M PB buffer, pH 7.0). The RSD for the same electrode (10 measurements) and different electrodes (5 electrodes) was respectively 2.32% and 3.51% (Table. S1). After being stored in refrigerator at 4 °C for one week, the electrode has no obvious change in peak current and shape in response to 0.1 mM H2O2 (Fig. S4). The electrode shows the satisfied reproducibility and stability. Common interferences for H2O2 detection such as glucose (GLU), uric acid (UA), and dopamine (DA) were tested for interfering effect. 2 mM GLU, 0.2 mM DA and 0.1 mM UA were injected in succession during the detection of H2O2. It could be seen from Fig. 7 that these electroactive substances did not induce any significant changes in the overall current responses at optimal potential (-0.4 V). On the contrary, the current increased instantly upon the successive addition of H2O2, which means GLU, UA and DA

Journal Pre-proof have not significant interference in the detection of H2O2.

4 Conclusions In summary, we prepared a H2O2 sensor based on Ag@PDA-NTs/GCE. The successful preparation and morphology of Ag@PDA-NTs were investigated by SEM and TEM. Raman spectroscopy was used to analyze the chemical structure of PDA-NTs and Ag@PDA-NTs, which found their structure have some similarities to MWCNTs. Ag@PDA-NTs has obviously better dispersivity than Ag@MWCNTs for further electrode preparation. The best electrocatalytic ability of

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H2O2 was achieved by modified electrode using 10 mg/mL AgNO3 during the Ag@PDA-NTs

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preparation. The linear range of the modified electrode was from 5 μM to 200 μM with a detection limit of 0.68 μM. In addition, it also showed good reproducibility, long-term stability and interfering

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effect against GLU, UA and DA. As analogs for MWCNTs, although MWCNTs has better

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mechanical strength and electron transfer ability, PDA-NTs is easy to be modified and dispersed in

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solvent which are both vital in electrochemical material application. On account of its easy preparation, this modified electrode can make a H2O2 sensor that has good applications in areas

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Acknowledgment

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including biosensor, analytical and electroanalytical chemistry.

This work was supported by the National Natural Science Foundation of China (21636003 and 21672065), the Natural Science Foundation of Shanghai (19ZR1412400) and the Fundamental Research Funds for the Central Universities (22221818014).

Conflicts of interest The authors declared that they have no conflicts of interest to this work. Reference [1]Ahuja, T., Kumar, D., Recent progress in the development of nano-structured conducting polymers/nanocomposites for sensor applications, Sens. Actuators, B 136 (1) (2009) 275–286. https://doi.org/10.1016/j.snb.2008.09.014 [2]Hwang, J. Y., Shin, U. S., Jang, W. C., Hyun, J. K., Wall, I. B., Kim, H. W., Biofunctionalized carbon nanotubes in neural regeneration: a mini-review, Nanoscale 5 (2) (2013) 487–497. https://doi.org/10.1039/C2NR31581E

Journal Pre-proof [3]Liu, Y., Ai, K., Lu, L., Polydopamine and its derivative materials: synthesis and promising applications in energy, environmental, and biomedical fields, Chem. Rev. 114 (9) (2014) 5057–5115. https://doi.org/10.1021/cr400407a [4]Dreyer, D. R., Miller, D. J., Freeman, B. D., Paul, D. R., Bielawski, C. W., Perspectives on poly (dopamine), Chem. Sci. 4 (10) (2013) 3796–3802. https://doi.org/10.1039/C3SC51501J [5]Ye, Q., Zhou, F., Liu, W., Bioinspired catecholic chemistry for surface modification, Chem. Soc. Rev. 40 (7) (2011) 4244–4258. https://doi.org/10.1039/C1CS15026J [6]Lee, H., Dellatore, S. M., Miller, W. M., Messersmith, P. B., Mussel-inspired surface chemistry for multifunctional coatings, Sci. 318 (5849) (2007) 426–430. https://doi.org/10.1126/science.1147241

of

[7]Liu, X., Cao, J., Li, H., Li, J., Jin, Q., Ren, K., Ji, J., Mussel-Inspired Polydopamine: A Biocompatible and

ro

Ultrastable Coating for Nanoparticles in Vivo, ACS Nano 7 (10) (2013) 9384–9395.

-p

https://doi.org/10.1021/nn404117j

[8]d'Ischia, M., Napolitano, A., Pezzella, A., Meredith, P., Sarna, T., Chemical and structural diversity in

re

eumelanins: unexplored bio‐optoelectronic materials, Angew. Chem. Int. Edit. 48 (22) (2009) 3914–3921.

lP

https://doi.org/10.1002/anie.200803786

[9]Zhang, S., Zhang, Y., Bi, G., Liu, J., Wang, Z., Xu, Q., Xu, H., Li, X., Mussel-inspired polydopamine

na

biopolymer decorated with magnetic nanoparticles for multiple pollutants removal, J. Hazard. Mater. 270 (2014) 27–34. https://doi.org/10.1016/j.jhazmat.2014.01.039

Jo ur

[10]Cui, J., Yan, Y., Such, G. K., Liang, K., Ochs, C. J., Postma, A., Caruso, F., Immobilization and intracellular delivery of an anticancer drug using mussel-inspired polydopamine capsules, Biomacromolecules 13 (8)(2012) 2225–2228. https://doi.org/10.1021/bm300835r [11]Qiang, W., Li, W., Li, X., Chen, X., Xu, D., Bioinspired polydopamine nanospheres: a superquencher for fluorescence sensing of biomolecules, Chem. Sci. 5 (8) (2014) 3018–3024. https://doi.org/10.1039/C4SC00085D [12]Chen, T., Shao, M., Xu, H., Zhuo, S., Liu, S., Lee, S. T., Molecularly imprinted polymer-coated silicon nanowires for protein specific recognition and fast separation, J. Mater. Chem. 22 (9) (2012) 3990–3996. https://doi.org/10.1039/C2JM14329A [13]Kim, S., Park, C. B., Mussel-inspired transformation of CaCO3 to bone minerals, Biomaterials 31 (25) (2010) 6628–6634. https://doi.org/10.1016/j.biomaterials.2010.05.004 [14]Yan, D., Xu, P., Xiang, Q., Mou, H., Xu, J., Wen, W., Li, X., Zhang, Y., Polydopamine nanotubes: bio-inspired synthesis, formaldehyde sensing properties and thermodynamic investigation, J. Mater. Chem. A 4 (9) (2016) 3487– 3493. https://doi.org/10.1039/C6TA00396F

Journal Pre-proof [15]Wang, A. J., Liao, Q. C., Feng, J. J., Yan, Z. Z., Chen, J. R., In situ synthesis of polydopamine–Ag hollow microspheres for hydrogen peroxide sensing, Electrochim. Acta 61 (2012) 31–35. https://doi.org/10.1016/j.electacta.2011.11.063 [16]Xu, H., Liu, X., Wang, D., Interfacial basicity-guided formation of polydopamine hollow capsules in pristine O/W emulsions–toward understanding of emulsion template roles, Chem. Mater. 23 (23) (2012) 5105–5110. https://doi.org/10.1021/cm2028417 [17]Lynge, M. E., van der Westen, R., Postma, A., Städler, B., Polydopamine—a nature-inspired polymer coating for biomedical science, Nanoscale 3 (12) (2011) 4916–4928. https://doi.org/10.1039/C1NR10969C

of

[18]Ronkainen, N. J., Halsall, H. B., Heineman, W. R., Electrochemical biosensors, Chem. Soc. Rev. 39 (5) (2010)

ro

1747–1763. https://doi.org/10.1039/B714449K

-p

[19]Pingarrón, J. M., Yañez-Sedeño, P., González-Cortés, A., Gold nanoparticle-based electrochemical biosensors, Electrochim. Acta 53 (19) (2008) 5848–5866. https://doi.org/10.1016/j.electacta.2008.03.005

re

[20]Luo, X., Morrin, A., Killard, A. J., Smyth, M. R., Application of Nanoparticles in Electrochemical Sensors and

lP

Biosensors, Electroanal. 18 (4) (2006) 319–326. https://doi.org/10.1002/elan.200503415 [21]Chen, W., Cai, S., Ren, Q. Q., Wen, W., Zhao, Y. D., Recent advances in electrochemical sensing for hydrogen

na

peroxide: a review, Analyst 137 (1) (2012) 49–58.https://doi.org/10.1039/C1AN15738H [22]Frattini, A., Pellegri, N., Nicastro, D., De Sanctis, O., Effect of amine groups in the synthesis of Ag

Jo ur

nanoparticles using aminosilanes, Mater. Chem.Phys. 94 (1) (2005) 148–152. https://doi.org/10.1016/j.matchemphys.2005.04.023 [23]Pillai, Z. S., Kamat, P. V., What Factors Control the Size and Shape of Silver Nanoparticles in the Citrate Ion Reduction Method? J. Phys. Chem. B 108 (3) (2004) 945–951. https://doi.org/10.1021/jp037018r [24]Han, Y., Zheng, J., Dong, S., A novel nonenzymatic hydrogen peroxide sensor based on Ag–MnO2–MWCNTs nanocomposites, Electrochim. Acta 90 (2013) 35–43. https://doi.org/10.1016/j.electacta.2012.11.117 [25]Lin, J., He, C., Zhao, Y., Zhang, S., One-step synthesis of silver nanoparticles/carbon nanotubes/chitosan film and its application in glucose biosensor, Sens. Actuators B 137 (2) (2009) 768–773. https://doi.org/10.1016/j.snb.2009.01.033 [26]Jeon, B. H., Yang, D. H., Kim, Y. D., Shin, J. S., Lee, C. S., Fabrication of silver nanoparticles in titanium dioxide/poly (vinyl alcohol) alternate thin films: A nonenzymatic hydrogen peroxide sensor application, Electrochim. Acta 292 (2018) 749–758. https://doi.org/10.1016/j.electacta.2018.08.125

Journal Pre-proof [27]Xue, J., Zheng, W., Wang, L.,Jin, Z., Scalable fabrication of polydopamine nanotubes based on curcumin crystals, ACS Biomater. Sci. Eng. 2 (4) (2016) 489–493. https://doi.org/10.1021/acsbiomaterials.6b00102 [28]Jiang, Y., Lu, Y., Zhang, L., Liu, L., Dai, Y., Wang, W., Preparation and characterization of silver nanoparticles immobilized on multi-walled carbon nanotubes by poly (dopamine) functionalization, J. Nanopart. Res. 14 (6) (2012) 938. https://doi.org/10.1007/s11051-012-0938-x [29]Mohamed, A. L., El-Naggar, M. E., Shaheen, T. I.,Hassabo, A. G., Novel nano polymeric system containing biosynthesized core shell silver/silica nanoparticles for functionalization of cellulosic based material, J. Microsyst. Technol. 22(5) (2016) 979-992. https://doi.org/10.1007/s00542-015-2776-0

of

[30]Dai, K., Shi, L., Fang, J., Zhang, Y., Synthesis of silver nanoparticles on functional multi-walled carbon

ro

nanotubes, J. Mater. Sci. Eng. A, 465(1-2) (2007) 283-286. https://doi.org/10.1016/j.msea.2007.03.052

-p

[31]Liu, Y., Pan, C., Wang, J., Raman spectra of carbon nanotubes and nanofibers prepared by ethanol flames, J. Mater. Sci. 39 (3) (2004) 1091–1094. https://doi.org/10.1023/B:JMSC.0000012952.20840.09

re

[32]Wang, F., Han, R., Liu, G., Chen, H., Ren, T., Yang, H., Wen, Y., Construction of polydopamine/silver

lP

nanoparticles multilayer film for hydrogen peroxide detection, J. Electroanal. Chem. 706 (2013) 102–107. https://doi.org/10.1016/j.jelechem.2013.08.008

na

[33]Juang, F. R., Chern, W. C., Octahedral Cu2O nanoparticles decorated by silver catalyst for high sensitivity nonenzymatic H2O2 detection, Mat. Sci. Semicon. Proc. 101 (2019) 156–163.

Jo ur

https://doi.org/10.1016/j.mssp.2019.05.034

[34]Kurowska, E., Brzózka, A., Jarosz, M., Sulka, G. D., Jaskuła, M., Silver nanowire array sensor for sensitive and rapid detection of H2O2, Electrochim. Acta 104 (2013) 439–447. https://doi.org/10.1016/j.electacta.2013.01.077 [35]Zhao, W., Wang, H., Qin, X., Wang, X., Zhao, Z., Miao, Z., Chen L., Shan, M., Fang, Y., Chen, Q., A novel nonenzymatic hydrogen peroxide sensor based on multi-wall carbon nanotube/silver nanoparticle nanohybrids modified gold electrode, Talanta 80 (2) (2009) 1029–1033. https://doi.org/10.1016/j.talanta.2009.07.055 [36]Shi, Y., Liu, Z., Zhao, B., Sun, Y., Xu, F., Zhang, Y., Wen, Z., Yang, H., Li, Z., Carbon nanotube decorated with silver nanoparticles via noncovalent interaction for a novel nonenzymatic sensor towards hydrogen peroxide reduction, J. Electroanal. Chem. 656 (1–2) (2011) 29–33. https://doi.org/10.1016/j.jelechem.2011.01.036 [37]Wu, S., Zhao, H., Ju, H., Shi, C., Zhao, J., Electrodeposition of silver–DNA hybrid nanoparticles for electrochemical sensing of hydrogen peroxide and glucose, Electrochem. Commun. 8 (8) (2006) 1197–1203. https://doi.org/10.1016/j.elecom.2006.05.013

Journal Pre-proof [38]Mahmoudian, M. R., Alias, Y., Basirun, W. J., Ebadi, M., Preparation of ultra-thin polypyrrole nanosheets decorated with Ag nanoparticles and their application in hydrogen peroxide detection, Electrochim. Acta 72 (2012)

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46–52. https://doi.org/10.1016/j.electacta.2012.03.144

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Figures and captions:

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Schemes 1. Schematic of preparation of Ag@PDA-NTs/GCE

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Fig. 1 SEM and TEM images of PDA-NTs and Ag@PDA-NTs. (a) SEM image of Ag@PDA-NTs. (b) TEM image

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of Ag@PDA-NTs. (c) Crystal lattice of AgNPs (d) Electron diffraction pattern of AgNPs.

Fig. 2 Dispersivity of Ag@PDA-NTs and Ag@MWCNTs in alcohol.

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Fig. 3a Raman spectrum of PDA-NTs and Ag@PDA-NTs

Fig. 3b Raman spectrum of MWCNTs and Ag@MWCNTs

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Fig. 4 The CVs of different modified GCEs. (a) CVs of GCE (black), PDA-NTs/GCE (red), Ag@PDA-NTs/GCE

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(blue) in 0.1 M PB (pH 7.0) containing 1 mM H2O2. (b) CVs of Ag@PDA-NTs/GCE prepared with different

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AgNO3 concentration (2, 4, 6, 10 mg/mL) in 0.1 M PB (pH 7.0) containing 1 mM H2O2 Scan rate: 0.1V s-1

Fig. 5 The responses of CVs at different conditions. (a) CVs for Ag@PDA-NTs in 0.1 M PB (pH 7.0) in the presence of H2O2 with different concentration (from the top: 0, 2, 4 and 6 mM). Scan rate: 0.1 V s-1. (b) CVs of Ag@PDA-NTs/GCE in 0.1 M PB buffer (pH 7.0) containing 1 mM H2O2 at different scan rates (from the top: 10, 25, 50, 75 ,100 ,125, 150, 175, 200 and 300 mV s-1) and plot of peak current of H2O2 versus ν1/2.

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Fig. 6 (a) Amperometric response of Ag@PDA-NTs/GCE on successive injection of H2O2 into 0.1 M PB buffer

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(pH 7.0). Applied potential: -0.4 Vand plot of H2O2 peak in current versus H2O2 concentration. (b) Plot of H2O2

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peak of wider range (0.001 mM - 5 mM) in current versus H2O2 concentration.and the amplification of linear

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response part of (b).

Fig. 7 Interfering effect of glucose (GLU), dopamine (DA) and uric acid (UA) on the performance of Ag@PDA-NTs/GCE in 0.1 M PB buffer (pH 7.0). Applied potential: -0.4 V.

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Graphical Abstract

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Lingfeng Gan: Data curation, Formal analysis, Investigation, Methodology, Writing - original draft; Chao Chen: Methodology, Resources; Peng Qin: Methodology; Yibing Wang: Conceptualization, Supervision, Writing - review & editing, Funding acquisition; Ping Wang: Writing - review & editing, Funding acquisition.

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The authors declared that they have no conflicts of interest to this work.

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Highlights PDA-NT was proved as an electrochemical analog for carbon nanotube by Raman spectroscopy. AgNPs fabricated PDA-NTs for construction of nanocomposite electrodes with good reproducibility, long-term stability.

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Linear range of the modified electrode was from 5 μM to 200 μM with a detection limit of 0.68 μM for H2O2.