Fabrication of Biosensor Based on Polyaniline/Gold Nanorod Composite

Abstract

This present paper describes a new approach to fabricate a new amperometric sensor for the determination of glucose. Polyaniline (PANI) film doped with colloidal gold nanorod particles has been used to immobilize glucose oxidase by glutaraldehyde. The polyaniline/gold nanorod composite structure gave an excellent matrix for enzyme immobilization due to the large specific surface area and higher electroactivity. The composite has been characterized by cyclic voltammetry (CV), scanning electron microscopy (SEM), and surface-enhanced Raman spectroscopy (SERS). The SERS spectrum of the surface-immobilized glucose oxidase and the spectrum of the native enzyme indicate that the main feature of the native structure of glucose oxidase was conserved after being immobilized on the polymer matrix. The amperometric response was measured as a function of concentration of glucose at a potential of 0.6 V versus Ag/AgCl in 0.1 M phosphate buffer at pH 6.4. Linear range of the calibration curve was from 17.6 μM to 1 mM with a sensitivity of 13.8 μA⋅mM−1⋅cm−2and a limit of detection (LOD) of 5.8 μM. The apparent Michaelis-Menten constantKMwas calculated as 1.0 mM and the response time was less than 3 seconds.

Dispersed Conducting Polymer Nanocomposites with Glucose Oxidase and Gold Nanoparticles for the Design of Enzymatic Glucose Biosensors

“…The developed glucose biosensor based on the GR electrode modified by PANI-AuNPs (6 nm) -GOx/GOx was 3.14 times more stable than that of the Pt/PANI/gold nanorod composites/GOx electrode without mediator ( τ 1/2 was determined as 7.0 days) [ 44 ]. The glucose biosensor based on the GR/Ppy-AuNPs (6 nm) -GOx/GOx electrode was 1.73 times more stable than that previously reported for biosensors based on the GR electrode with electrochemical deposited AuNPs (13nm) , immobilized GOx and modified by Ppy (9.8 days of τ 1/2 ) [ 38 ].…”

Amperometric Glucose Biosensor Based on Electrochemically Deposited Gold Nanoparticles Covered by Polypyrrole

“…The developed Ppy (21h) /GOx/ AuNPs/GR electrode had very similar linear detection interval (up to 19.9 mmol L À1 ) if compared with Ppy (3h) / GOx/AuNPs (13nm) /GR based on non-electrochemically deposited AuNPs, where the linear detection interval was extended up to 20 mmol L À1 [9]. In our case the linear range of glucose detection was wider if compared with amperometric glucose biosensors operating without redox mediators ( Table 2): for biosensor based on the Pt electrode functionalized through a layer-by-layer assembly of single-walled carbon nanotubes and multilayer films composed of chitosan, AuNPs and GOx the linear range was up to 0.81 mmol L À1 [39]; for biosensor based on polyaniline/gold nanorod/GOx -up to 1 mmol L À1 [40]; for biosensor based on printed polyimide/carbon/AuNPs/ GOx -up to 1.5 mmol L À1 [41]; for biosensor based on GOx, Nafion and AuNPs deposited on the Pt electrode covered with rhodium nanoparticles -up to 15 mmol L À1 [42].…”

“…Tamer et al [40] Multilayer films of GOx and AuNPs (12 nm) on Au electrode 0.008 mmol L À1 / 5.72 mA mM À1 cm À2 0.01 -13 mmol L À1…”

“…German et al [35] The immobilization of GOx on electrochemically deposited AuNPs on graphite electrode 0.083 mmol L À1 / 101.02 mA mM À1 cm À2 0.1 -10 mmol L À1 Amperometry Phenazine methosulfate German et al [10] GOx immobilised on electrochemically deposited AuNPs on graphite electrode and covered by polypyrrole The immobilization of GOx on an overoxidized polypyrrole film decorated with electrochemically deposited AuNPs (200 nm) on glassy carbon electrode 0.20 mmol L À1 / 21.7 mA mM À1 cm À2 0.5 mmol L -1 / 3.07 mA mM -1 cm -2 0.7 mmol L -1 / 12.0 mA mM -1 cm -2 0.99 -19.9 mmol L À1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 operating without redox mediator (13.8 mA mM À1 cm À2 ) [40] (Table 2).…”

“…As it is seen from figure 6 A the t 1/2 for developed GOx/AuNPs/GR and Ppy (21h) /GOx/ AuNPs/GR electrodes was 3.85 and 9.80 days. The stability of biosensor based on polyaniline/gold nanorod composite/GOx electrode operating without mediator was 7 days [40]. The modification of glucose biosensors by polypyrrole is preferred in order to improve the stability of electrodes.…”