- Email: [email protected]
One-step electrochemical deposition of Polypyrrole–Chitosan–Iron oxide nanocomposite films for non-enzymatic glucose biosensor
Author’s Accepted Manuscript One-step Electrochemical Deposition of Polypyrrole-Chitosan-Iron Oxide Nanocomposite Films for Non-Enzymatic Glucose Biosensor Ali M.A. Abdul Amir AL-Mokaram, Rosiyah Yahya, Mahnaz M Abdi, Habibun Nabi Muhammad Ekramul Mahmud www.elsevier.com
PII: DOI: Reference:
S0167-577X(16)31142-9 http://dx.doi.org/10.1016/j.matlet.2016.07.049 MLBLUE21177
To appear in: Materials Letters Received date: 17 April 2016 Revised date: 20 June 2016 Accepted date: 11 July 2016 Cite this article as: Ali M.A. Abdul Amir AL-Mokaram, Rosiyah Yahya, Mahnaz M Abdi and Habibun Nabi Muhammad Ekramul Mahmud, One-step Electrochemical Deposition of Polypyrrole-Chitosan-Iron Oxide Nanocomposite Films for Non-Enzymatic Glucose Biosensor, Materials Letters, http://dx.doi.org/10.1016/j.matlet.2016.07.049 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
1 One-step Electrochemical Deposition of Polypyrrole-Chitosan-Iron Oxide Nanocomposite Films for Non-Enzymatic Glucose Biosensor Ali M.A. Abdul Amir AL-Mokarama,b*, Rosiyah Yahyaa, Mahnaz M Abdic,d and Habibun Nabi Muhammad Ekramul Mahmuda* a
Department of Chemistry, Faculty of Science, University of Malaya, 50603, Kuala Lumpur, Malaysia.
b
Department of Chemistry, College of Science, Al-Mustansiriya University,10052- Baghdad, Iraq.
c
Department of Chemistry, Faculty of Science, University Putra Malaysia, 43400 Serdang, Malaysia.
d
Institute of Tropical Forestry and Forest Products, University Putra Malaysia,43400 Serdang, Malaysia. Tel.+60379672532; *email: [email protected] Tel.+60123138015; *email: [email protected]
ABSTRACT One-step electrodeposition method of Polypyrrole-Chitosan-Iron oxide (Ppy-CS-Fe3O4) nanocomposite films (Ppy-CS-Fe3O4NP/ITO) has been developed for the fabrication of advanced composite coatings for biosensors applications. The FESEM and EDX results provide the evidence of successful incorporation of Fe3O4 into Ppy-CS molecules. The presence of Fe3O4 nanoparticles in the nanocomposite films was further confirmed by the XRD and XPS spectrums. The fabricated electrode Ppy-CS-Fe3O4 NP/ITO shows a fast amperometric response with good selectivity to detect glucose non-enzymatically with improved linearity (1–16 mM) and the detection limit of (234 μM) at a signal-to-noise ratio (S/N = 3.0). Keywords: Electrodeposition; Glucose biosensor; Nanocomposites; Iron oxide nanoparticles; X-ray techniques; XPS. 1.
Introduction
In recent years, many researchers have concentrated on the development of glucose biosensors because of their extensive applications in clinical diagnosis [1,2]. The detection of glucose in the blood is the most feasible approach for the measurement of blood sugar concentration [3]. Glucose sensors have already experienced the development of sensors based on enzymatic catalysts and non-enzymatic catalysts. In the past decades, three-generation enzymatic glucose sensors have been developed, but they suffer from the inherent instability of the enzyme due to its pH and temperature sensitivity as well as sensor performance variation due to oxygen concentration variability [4,5]. Additionally, the high cost of enzyme also limits the wide application of enzymatic glucose biosensors in developing countries. Due to the above-
2 mentioned factors, considerable research efforts have been focused on the development of non-enzymatic glucose sensors which allow glucose to be oxidised directly on the electrode surface [6,7]. In order to develop sensitive non-enzymatic glucose sensors, a variety of metals and metal oxides, have been explored [8-11]. Materials such as films or nanocomposite films serve the purpose [12]. Newer approaches focus on developing nanocomposite films. In the bulky polypyrrole (Ppy), electron transfer is relatively slow but coupling with nanostructured materials, the sensitivity is increased due to faster diffusion in the sensing area. The objective of these approaches is to enhance the sensing capabilities of biosensors, such as sensitivity, stability, biocompatibility, reproducibility, and selectivity [13]. Amperometric electrochemical electrodes are receiving widespread attention due to their simplicity, fast response time, and sensitivity to a wide range of biomolecules [14]. These biosensors operate on applying a base current between a working electrode and reference electrode, with the reduction or oxidation of a compound causing a shift in the current allowing for quantification of the specific molecules [15]. The nanomaterials in biosensors support the biocompatibility, lifetime, and have been found cost effective [16,17]. Iron oxide (Fe3O4) nanoparticles in composite films have been used for glucose sensors to contribute the electron transfer and increase the surface area of the sensors and thus possess the good electrocatalytic activity [18]. The combination of both metal oxide and the polymeric features throughout the nanocomposite structure lead to great potentials in glucose sensors [19,20]. Herein, we report a novel non-enzymatic glucose sensor produced directly by one-step electrochemical deposition of Ppy-CS-Fe3O4 films which has not been addressed before. 2.
Experimental
Preparation of PPY-CS- Fe3O4 nanocomposite film Fe3O4 nanoparticles were dispersed into 25 mL of Cs (0.5 mg/mL) solution in acetic acid under continuous stirring at room temperature after which it was sonicated for about 2 h to obtain a viscous solution of CS with uniformly dispersed Fe3O4 nanoparticles. Later the solution of pyrrole and (p-TS) (10 ml) was added to the solution of CS and iron oxide and was stirred for 5 minutes. The prepared solution of Ppy-CS- Fe3O4 NP was taken in a glass cell for electrochemical deposition of the film on ITO glass electrode by cyclic voltammetry using three electrode system. The nanocomposite films were then washed repeatedly with distilled water to remove any unbound particles and later dried at room temperature. The detailed mechanism for the deposition is provided in supporting supplementary information (section 2.1).
3 3.
Results and discussion
The X-ray diffraction (XRD) patterns of Ppy-CS composite and Ppy-CS-Fe3O4 nanocomposite are shown in (Fig.1a) and (Fig.1b), respectively. The XRD pattern of Ppy-CS indicating the amorphous form of Ppy-CS composite film (Fig.1a). However, in Ppy-CS-Fe3O4 nanocomposite film, some new sharp peaks at 2 theta 21, 29, 34, 37, 45, 50 and 60 degrees have been observed due to the presence of Fe3O4 nanoparticles in the composite films. The XRD pattern of these Ppy-CS-Fe3O4 nanocomposite films (Fig.1b) are polycrystalline in nature [21].
Fig.1: (a) XRD Ppy-CS, (b) XRD Ppy-CS-Fe3O4 nanocomposites (c) XPS Ppy-CS/ITO, (d) XPS Ppy-CSFe3O4 nanocomposites /ITO The presence of Fe3O4 nanoparticles in the nanocomposite films was further confirmed by X-ray photoelectron spectroscopy (XPS). The XPS wide scan of Ppy-CS composite films and Ppy-CS-Fe3O4 nanocomposite films was employed to identify and analyze the chemical components of the films as depicted in (Fig.1c) and (Fig.1d), respectively. The major peaks such as C 1S, O 1S, N 1S were present in the
4 curves for Ppy-CS composite films and Ppy-CS Fe3O4 nanocomposite films. New peaks located at the binding energies of 710 eV and 51 eV are assigned to Fe2p and Fe3p, respectively. In (Fig. 1d), the iron in Ppy-CS-Fe3O4 nanocomposite films clearly shows the linkage of Fe 3O4 nanoparticles onto Ppy-CS composition (Fig. 1c). These peaks of Fe2p and Fe3p are for Fe304 nanoparticles. [22,23]. The glucose sensing performances of Ppy-CS-Fe3O4 nanocomposite /ITO and Ppy-CS/ITO electrodes were carefully examined by cyclic voltammetry (CV) in (Fig. 2a) and (Fig. 2b) with and without glucose, respectively. The peak currents for Ppy-CS-Fe3O4 nanocomposite /ITO were found to increase dramatically with the addition of 1 mM glucose indicating a good glucose sensing. The peak currents for Ppy-CS/ITO electrode were observed much lower than that of Ppy-CS-Fe3O4 nanocomposite /ITO electrode, after adding 1 mM glucose indicating the role of Fe3O4 nanoparticle in glucose sensing.
Fig. 2: (a) CV responses of Ppy-CS-Fe3O4 nanocomposite /ITO in 0.1 M NaOH electrolyte with 1 mM glucose and without glucose at the scan rate of 50 mV s-1 (b) CV responses of Ppy-CS/ITO in 0.1 M NaOH electrolyte with 1 mM glucose and without glucose at the scan rate of 50 mV s-1. Fig. 3 shows typical steady-state amperometric responses of Ppy-CS-Fe3O4 nanocomposite /ITO and PpyCS /ITO on successively increasing glucose concentrations at an applied potential of +0.18 V (vs. Ag/AgCl). Ppy-CS-Fe3O4 nanocomposite /ITO shows linearly increased responses to the change of glucose concentrations while the current responses of Ppy-CS/ITO were much lower and only show slight increase with the addition of glucose into the cell. The results are consistent with those obtained from cyclic voltammograms. The calibration curve for Ppy-CS-Fe3O4 nanocomposite /ITO is presented in the inset of Fig. 3. The glucose sensors show linear dependence in the glucose concentration of dynamic range of 1 to 16 mM with a correlation coefficient of 0.967, a sensitivity of 12 µAcm-2 mM−1, and a detection
5 limit of 234 μM (S/N=3). This novel Ppy-CS-Fe3O4 nanocomposite /ITO glucose sensor exhibits high sensitivity, low detection limit and fast response time in less than 3 second.
Fig. 3: Amperometric responses to successive addition of glucose concentration in 0.1M NaOH solution at +0.18 V (vs. Ag/AgCl). The inset shows the steady-state calibration curve for the of Ppy-CS-Fe3O4 nanocomposite /ITO electrode 4.
Conclusions
In summary, a one-step electrochemical synthesis procedure has been followed to prepare Ppy-CS-Fe3O4 nanocomposite films on ITO glass electrode successfully from an aqueous solution containing the monomer, dopant ions, nanoparticles and bio-polymers for glucose sensing. A high glucose sensing performance has been demonstrated by this fabricated sensor with high sensitivity, selectivity, fast response time and low detection limit due to the homogeneous film formation by this one-step electrochemical process. The advantages of low-cost precursor and the simple preparation technique will make the material a promising economical candidate in glucose sensing. Acknowledgments The authors would like to acknowledge the financial supports from the Ministry of Higher Education, Malaysia for the Fundamental Research Grant Scheme (FRGS) (Project No. FP034-2013A) and the University of Malaya Postgraduate Research Grant (PPP) (Project No: PG111-2013A). References [1] Song S, Xu H, Fan C. Potential diagnostic applications of biosensors: current and future directions. International journal of nanomedicine.4 (2006) 433.
6 [2] Huang L, Guo Y, Peng Z, Porter AL. Characterising a technology development at the stage of early emerging
applications:
nanomaterial-enhanced
biosensors.
Technology
Analysis
&
Strategic
Management. 23 (2011) 527-44. [3] Koschwanez HE, Reichert WM. In vitro, in vivo and post explantation testing of glucose-detecting biosensors: current methods and recommendations. Biomaterials. 28 (2007) 3687-703. [4] Karyakin AA, Vuki M, Lukachova LV, Karyakina EE, Orlov AV, Karpachova GP, Wang J. Processible polyaniline as an advanced potentiometric pH transducer. Application to biosensors. Analytical chemistry. 71(1999) 2534-40. [5] Ramanavicius A, Kausaite A, Ramanaviciene A, Acaite J, Malinauskas A. Redox enzyme–glucose oxidase–initiated synthesis of polypyrrole. Synthetic Metals. 156 (2006) 409-13. [6] Welch CM, Compton RG. The use of nanoparticles in electroanalysis: a review. Analytical and bioanalytical chemistry. 384 (2006) 601-19. [7] Zhang H, Zhong X, Xu JJ, Chen HY. Fe3O4/polypyrrole/Au nanocomposites with core/shell/shell structure: synthesis, characterization, and their electrochemical properties. Langmuir. 24 (2008)13748-52. [8] Xiao X, Li H, Pan Y, Si P. Non-enzymatic glucose sensors based on controllable nanoporous gold/copper oxide nanohybrids. Talanta. 125 (2014) 366-71. [9] Kiani MA, Tehrani MA, Sayahi H. Reusable and robust high sensitive non-enzymatic glucose sensor based on Ni (OH)2 nanoparticles. Analytica chimica acta. 839 (2014) 26-33. [10] Marilyn W, Jun HS, Waldemar G. Amperometric Determination of Glucose at Conventional vs. Nanostructured Gold Electrodes in Neutral Solutions. Electroanalysis 22 (2010) 1275-1277. [11] Waldemar G, Robert T . Electrocatalyst for non-enzymatic oxidation of glucose in neutral saline solutions. Electroanal. Chem. 424 (1997) 43-48. [12] Kaur G, Adhikari R, Cass P, Bown M, Gunatillake P. Electrically conductive polymers and composites for biomedical applications. RSC Advances. 5 (2015) 37553-67. [13] Esmaeili C, Abdi MM, Mathew AP, Jonoobi M, Oksman K, Rezayi M. Synergy Effect of Nanocrystalline Cellulose for the Biosensing Detection of Glucose. Sensors. 15 (2015) 24681-97. [14] Masoomi-Godarzi S, Khodadadi AA, Vesali-Naseh M, Mortazavi Y. Highly stable and selective nonenzymatic glucose biosensor using carbon nanotubes decorated by Fe 3O4 nanoparticles. Journal of The Electrochemical Society. 161 (2014) 19-25.
7 [15] Thévenot DR, Toth K, Durst RA, Wilson GS. Electrochemical biosensors: recommended definitions and classification. Biosensors and Bioelectronics. 16 (2001) 121-31. [16] Toghill KE, Compton RG. Electrochemical non-enzymatic glucose sensors: a perspective and an evaluation. Int J Electrochem Sci. 5 (2010) 1246-301. [17] Chen A, Chatterjee S. Nanomaterials based electrochemical sensors for biomedical applications. Chemical Society Reviews. 42 (2013) 5425-38. [18] He Z, Gudavarthy RV, Koza JA, Switzer JA. Room-temperature electrochemical reduction of epitaxial magnetite films to epitaxial iron films. Journal of the American Chemical Society. 133 (2011) 12358-61. [19] Chen J, Zhang WD, Ye JS. Nonenzymatic electrochemical glucose sensor based on MnO2/MWNTs nanocomposite. Electrochemistry Communications. 10 (2008) 1268-71. [20] Chen X, Wu G, Cai Z, Oyama M, Chen X. Advances in enzyme-free electrochemical sensors for hydrogen peroxide, glucose, and uric acid. Microchimica Acta. 181 (2014) 689-705. [21] Ayad M, Salahuddin N, Fayed A, Bastakoti BP, Suzuki N, Yamauchi Y. Chemical design of a smart chitosan–polypyrrole–magnetite nanocomposite toward efficient water treatment. Physical Chemistry Chemical Physics.16(2014) 21812-9. [22] Yamashita T, Hayes P. Analysis of XPS spectra of Fe
2+
and Fe
3+
ions in oxide materials. Applied
Surface Science. 254 (2008) 2441-9. [23] Cheng FY, Su CH, Yang YS, Yeh CS, Tsai CY, Wu CL, Wu MT, Shieh DB. Characterization of aqueous dispersions of Fe3O4 nanoparticles and their biomedical applications. Biomaterials. 26 (2005) 729-38. Highlights
Ppy-CS-Fe3O4NP/ITO nanocomposite films has been developed for glucose sensing
The successful preparation of the films has been confirmed by XRD, XPS and SEM
The films showed improved response to detect glucose non-enzymatically
The developed sensor has detected glucose selectively with LOD of 234 μM
PII: DOI: Reference:
S0167-577X(16)31142-9 http://dx.doi.org/10.1016/j.matlet.2016.07.049 MLBLUE21177
To appear in: Materials Letters Received date: 17 April 2016 Revised date: 20 June 2016 Accepted date: 11 July 2016 Cite this article as: Ali M.A. Abdul Amir AL-Mokaram, Rosiyah Yahya, Mahnaz M Abdi and Habibun Nabi Muhammad Ekramul Mahmud, One-step Electrochemical Deposition of Polypyrrole-Chitosan-Iron Oxide Nanocomposite Films for Non-Enzymatic Glucose Biosensor, Materials Letters, http://dx.doi.org/10.1016/j.matlet.2016.07.049 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
1 One-step Electrochemical Deposition of Polypyrrole-Chitosan-Iron Oxide Nanocomposite Films for Non-Enzymatic Glucose Biosensor Ali M.A. Abdul Amir AL-Mokarama,b*, Rosiyah Yahyaa, Mahnaz M Abdic,d and Habibun Nabi Muhammad Ekramul Mahmuda* a
Department of Chemistry, Faculty of Science, University of Malaya, 50603, Kuala Lumpur, Malaysia.
b
Department of Chemistry, College of Science, Al-Mustansiriya University,10052- Baghdad, Iraq.
c
Department of Chemistry, Faculty of Science, University Putra Malaysia, 43400 Serdang, Malaysia.
d
Institute of Tropical Forestry and Forest Products, University Putra Malaysia,43400 Serdang, Malaysia. Tel.+60379672532; *email: [email protected] Tel.+60123138015; *email: [email protected]
ABSTRACT One-step electrodeposition method of Polypyrrole-Chitosan-Iron oxide (Ppy-CS-Fe3O4) nanocomposite films (Ppy-CS-Fe3O4NP/ITO) has been developed for the fabrication of advanced composite coatings for biosensors applications. The FESEM and EDX results provide the evidence of successful incorporation of Fe3O4 into Ppy-CS molecules. The presence of Fe3O4 nanoparticles in the nanocomposite films was further confirmed by the XRD and XPS spectrums. The fabricated electrode Ppy-CS-Fe3O4 NP/ITO shows a fast amperometric response with good selectivity to detect glucose non-enzymatically with improved linearity (1–16 mM) and the detection limit of (234 μM) at a signal-to-noise ratio (S/N = 3.0). Keywords: Electrodeposition; Glucose biosensor; Nanocomposites; Iron oxide nanoparticles; X-ray techniques; XPS. 1.
Introduction
In recent years, many researchers have concentrated on the development of glucose biosensors because of their extensive applications in clinical diagnosis [1,2]. The detection of glucose in the blood is the most feasible approach for the measurement of blood sugar concentration [3]. Glucose sensors have already experienced the development of sensors based on enzymatic catalysts and non-enzymatic catalysts. In the past decades, three-generation enzymatic glucose sensors have been developed, but they suffer from the inherent instability of the enzyme due to its pH and temperature sensitivity as well as sensor performance variation due to oxygen concentration variability [4,5]. Additionally, the high cost of enzyme also limits the wide application of enzymatic glucose biosensors in developing countries. Due to the above-
2 mentioned factors, considerable research efforts have been focused on the development of non-enzymatic glucose sensors which allow glucose to be oxidised directly on the electrode surface [6,7]. In order to develop sensitive non-enzymatic glucose sensors, a variety of metals and metal oxides, have been explored [8-11]. Materials such as films or nanocomposite films serve the purpose [12]. Newer approaches focus on developing nanocomposite films. In the bulky polypyrrole (Ppy), electron transfer is relatively slow but coupling with nanostructured materials, the sensitivity is increased due to faster diffusion in the sensing area. The objective of these approaches is to enhance the sensing capabilities of biosensors, such as sensitivity, stability, biocompatibility, reproducibility, and selectivity [13]. Amperometric electrochemical electrodes are receiving widespread attention due to their simplicity, fast response time, and sensitivity to a wide range of biomolecules [14]. These biosensors operate on applying a base current between a working electrode and reference electrode, with the reduction or oxidation of a compound causing a shift in the current allowing for quantification of the specific molecules [15]. The nanomaterials in biosensors support the biocompatibility, lifetime, and have been found cost effective [16,17]. Iron oxide (Fe3O4) nanoparticles in composite films have been used for glucose sensors to contribute the electron transfer and increase the surface area of the sensors and thus possess the good electrocatalytic activity [18]. The combination of both metal oxide and the polymeric features throughout the nanocomposite structure lead to great potentials in glucose sensors [19,20]. Herein, we report a novel non-enzymatic glucose sensor produced directly by one-step electrochemical deposition of Ppy-CS-Fe3O4 films which has not been addressed before. 2.
Experimental
Preparation of PPY-CS- Fe3O4 nanocomposite film Fe3O4 nanoparticles were dispersed into 25 mL of Cs (0.5 mg/mL) solution in acetic acid under continuous stirring at room temperature after which it was sonicated for about 2 h to obtain a viscous solution of CS with uniformly dispersed Fe3O4 nanoparticles. Later the solution of pyrrole and (p-TS) (10 ml) was added to the solution of CS and iron oxide and was stirred for 5 minutes. The prepared solution of Ppy-CS- Fe3O4 NP was taken in a glass cell for electrochemical deposition of the film on ITO glass electrode by cyclic voltammetry using three electrode system. The nanocomposite films were then washed repeatedly with distilled water to remove any unbound particles and later dried at room temperature. The detailed mechanism for the deposition is provided in supporting supplementary information (section 2.1).
3 3.
Results and discussion
The X-ray diffraction (XRD) patterns of Ppy-CS composite and Ppy-CS-Fe3O4 nanocomposite are shown in (Fig.1a) and (Fig.1b), respectively. The XRD pattern of Ppy-CS indicating the amorphous form of Ppy-CS composite film (Fig.1a). However, in Ppy-CS-Fe3O4 nanocomposite film, some new sharp peaks at 2 theta 21, 29, 34, 37, 45, 50 and 60 degrees have been observed due to the presence of Fe3O4 nanoparticles in the composite films. The XRD pattern of these Ppy-CS-Fe3O4 nanocomposite films (Fig.1b) are polycrystalline in nature [21].
Fig.1: (a) XRD Ppy-CS, (b) XRD Ppy-CS-Fe3O4 nanocomposites (c) XPS Ppy-CS/ITO, (d) XPS Ppy-CSFe3O4 nanocomposites /ITO The presence of Fe3O4 nanoparticles in the nanocomposite films was further confirmed by X-ray photoelectron spectroscopy (XPS). The XPS wide scan of Ppy-CS composite films and Ppy-CS-Fe3O4 nanocomposite films was employed to identify and analyze the chemical components of the films as depicted in (Fig.1c) and (Fig.1d), respectively. The major peaks such as C 1S, O 1S, N 1S were present in the
4 curves for Ppy-CS composite films and Ppy-CS Fe3O4 nanocomposite films. New peaks located at the binding energies of 710 eV and 51 eV are assigned to Fe2p and Fe3p, respectively. In (Fig. 1d), the iron in Ppy-CS-Fe3O4 nanocomposite films clearly shows the linkage of Fe 3O4 nanoparticles onto Ppy-CS composition (Fig. 1c). These peaks of Fe2p and Fe3p are for Fe304 nanoparticles. [22,23]. The glucose sensing performances of Ppy-CS-Fe3O4 nanocomposite /ITO and Ppy-CS/ITO electrodes were carefully examined by cyclic voltammetry (CV) in (Fig. 2a) and (Fig. 2b) with and without glucose, respectively. The peak currents for Ppy-CS-Fe3O4 nanocomposite /ITO were found to increase dramatically with the addition of 1 mM glucose indicating a good glucose sensing. The peak currents for Ppy-CS/ITO electrode were observed much lower than that of Ppy-CS-Fe3O4 nanocomposite /ITO electrode, after adding 1 mM glucose indicating the role of Fe3O4 nanoparticle in glucose sensing.
Fig. 2: (a) CV responses of Ppy-CS-Fe3O4 nanocomposite /ITO in 0.1 M NaOH electrolyte with 1 mM glucose and without glucose at the scan rate of 50 mV s-1 (b) CV responses of Ppy-CS/ITO in 0.1 M NaOH electrolyte with 1 mM glucose and without glucose at the scan rate of 50 mV s-1. Fig. 3 shows typical steady-state amperometric responses of Ppy-CS-Fe3O4 nanocomposite /ITO and PpyCS /ITO on successively increasing glucose concentrations at an applied potential of +0.18 V (vs. Ag/AgCl). Ppy-CS-Fe3O4 nanocomposite /ITO shows linearly increased responses to the change of glucose concentrations while the current responses of Ppy-CS/ITO were much lower and only show slight increase with the addition of glucose into the cell. The results are consistent with those obtained from cyclic voltammograms. The calibration curve for Ppy-CS-Fe3O4 nanocomposite /ITO is presented in the inset of Fig. 3. The glucose sensors show linear dependence in the glucose concentration of dynamic range of 1 to 16 mM with a correlation coefficient of 0.967, a sensitivity of 12 µAcm-2 mM−1, and a detection
5 limit of 234 μM (S/N=3). This novel Ppy-CS-Fe3O4 nanocomposite /ITO glucose sensor exhibits high sensitivity, low detection limit and fast response time in less than 3 second.
Fig. 3: Amperometric responses to successive addition of glucose concentration in 0.1M NaOH solution at +0.18 V (vs. Ag/AgCl). The inset shows the steady-state calibration curve for the of Ppy-CS-Fe3O4 nanocomposite /ITO electrode 4.
Conclusions
In summary, a one-step electrochemical synthesis procedure has been followed to prepare Ppy-CS-Fe3O4 nanocomposite films on ITO glass electrode successfully from an aqueous solution containing the monomer, dopant ions, nanoparticles and bio-polymers for glucose sensing. A high glucose sensing performance has been demonstrated by this fabricated sensor with high sensitivity, selectivity, fast response time and low detection limit due to the homogeneous film formation by this one-step electrochemical process. The advantages of low-cost precursor and the simple preparation technique will make the material a promising economical candidate in glucose sensing. Acknowledgments The authors would like to acknowledge the financial supports from the Ministry of Higher Education, Malaysia for the Fundamental Research Grant Scheme (FRGS) (Project No. FP034-2013A) and the University of Malaya Postgraduate Research Grant (PPP) (Project No: PG111-2013A). References [1] Song S, Xu H, Fan C. Potential diagnostic applications of biosensors: current and future directions. International journal of nanomedicine.4 (2006) 433.
6 [2] Huang L, Guo Y, Peng Z, Porter AL. Characterising a technology development at the stage of early emerging
applications:
nanomaterial-enhanced
biosensors.
Technology
Analysis
&
Strategic
Management. 23 (2011) 527-44. [3] Koschwanez HE, Reichert WM. In vitro, in vivo and post explantation testing of glucose-detecting biosensors: current methods and recommendations. Biomaterials. 28 (2007) 3687-703. [4] Karyakin AA, Vuki M, Lukachova LV, Karyakina EE, Orlov AV, Karpachova GP, Wang J. Processible polyaniline as an advanced potentiometric pH transducer. Application to biosensors. Analytical chemistry. 71(1999) 2534-40. [5] Ramanavicius A, Kausaite A, Ramanaviciene A, Acaite J, Malinauskas A. Redox enzyme–glucose oxidase–initiated synthesis of polypyrrole. Synthetic Metals. 156 (2006) 409-13. [6] Welch CM, Compton RG. The use of nanoparticles in electroanalysis: a review. Analytical and bioanalytical chemistry. 384 (2006) 601-19. [7] Zhang H, Zhong X, Xu JJ, Chen HY. Fe3O4/polypyrrole/Au nanocomposites with core/shell/shell structure: synthesis, characterization, and their electrochemical properties. Langmuir. 24 (2008)13748-52. [8] Xiao X, Li H, Pan Y, Si P. Non-enzymatic glucose sensors based on controllable nanoporous gold/copper oxide nanohybrids. Talanta. 125 (2014) 366-71. [9] Kiani MA, Tehrani MA, Sayahi H. Reusable and robust high sensitive non-enzymatic glucose sensor based on Ni (OH)2 nanoparticles. Analytica chimica acta. 839 (2014) 26-33. [10] Marilyn W, Jun HS, Waldemar G. Amperometric Determination of Glucose at Conventional vs. Nanostructured Gold Electrodes in Neutral Solutions. Electroanalysis 22 (2010) 1275-1277. [11] Waldemar G, Robert T . Electrocatalyst for non-enzymatic oxidation of glucose in neutral saline solutions. Electroanal. Chem. 424 (1997) 43-48. [12] Kaur G, Adhikari R, Cass P, Bown M, Gunatillake P. Electrically conductive polymers and composites for biomedical applications. RSC Advances. 5 (2015) 37553-67. [13] Esmaeili C, Abdi MM, Mathew AP, Jonoobi M, Oksman K, Rezayi M. Synergy Effect of Nanocrystalline Cellulose for the Biosensing Detection of Glucose. Sensors. 15 (2015) 24681-97. [14] Masoomi-Godarzi S, Khodadadi AA, Vesali-Naseh M, Mortazavi Y. Highly stable and selective nonenzymatic glucose biosensor using carbon nanotubes decorated by Fe 3O4 nanoparticles. Journal of The Electrochemical Society. 161 (2014) 19-25.
7 [15] Thévenot DR, Toth K, Durst RA, Wilson GS. Electrochemical biosensors: recommended definitions and classification. Biosensors and Bioelectronics. 16 (2001) 121-31. [16] Toghill KE, Compton RG. Electrochemical non-enzymatic glucose sensors: a perspective and an evaluation. Int J Electrochem Sci. 5 (2010) 1246-301. [17] Chen A, Chatterjee S. Nanomaterials based electrochemical sensors for biomedical applications. Chemical Society Reviews. 42 (2013) 5425-38. [18] He Z, Gudavarthy RV, Koza JA, Switzer JA. Room-temperature electrochemical reduction of epitaxial magnetite films to epitaxial iron films. Journal of the American Chemical Society. 133 (2011) 12358-61. [19] Chen J, Zhang WD, Ye JS. Nonenzymatic electrochemical glucose sensor based on MnO2/MWNTs nanocomposite. Electrochemistry Communications. 10 (2008) 1268-71. [20] Chen X, Wu G, Cai Z, Oyama M, Chen X. Advances in enzyme-free electrochemical sensors for hydrogen peroxide, glucose, and uric acid. Microchimica Acta. 181 (2014) 689-705. [21] Ayad M, Salahuddin N, Fayed A, Bastakoti BP, Suzuki N, Yamauchi Y. Chemical design of a smart chitosan–polypyrrole–magnetite nanocomposite toward efficient water treatment. Physical Chemistry Chemical Physics.16(2014) 21812-9. [22] Yamashita T, Hayes P. Analysis of XPS spectra of Fe
2+
and Fe
3+
ions in oxide materials. Applied
Surface Science. 254 (2008) 2441-9. [23] Cheng FY, Su CH, Yang YS, Yeh CS, Tsai CY, Wu CL, Wu MT, Shieh DB. Characterization of aqueous dispersions of Fe3O4 nanoparticles and their biomedical applications. Biomaterials. 26 (2005) 729-38. Highlights
Ppy-CS-Fe3O4NP/ITO nanocomposite films has been developed for glucose sensing
The successful preparation of the films has been confirmed by XRD, XPS and SEM
The films showed improved response to detect glucose non-enzymatically
The developed sensor has detected glucose selectively with LOD of 234 μM