Biosensor Based on Self‐Assembling Glucose Oxidase and Dendrimer‐Encapsulated Pt Nanoparticles on Carbon Nanotubes for Glucose Detection

Abstract

A novel amperometric glucose biosensor based on layer-by-layer (LbL) electrostatic adsorption of glucose oxidase (GOx) and dendrimer-encapsulated Pt nanoparticles (Pt-DENs) on multiwalled carbon nanotubes (CNTs) was described. Anionic GOx was immobilized on the negatively charged CNTs surface by alternatively assembling a cationic Pt-DENs layer and an anionic GOx layer. Transmission electron microscopy images and z-potentials proved the formation of layer-by-layer nanostructures on carboxyl-functionalized CNTs. LbL technique provided a favorable microenvironment to keep the bioactivity of GOx and prevent enzyme molecule leakage. The excellent electrocatalytic activity of CNTs and Pt-DENs toward H 2 O 2 and special three-dimensional structure of the enzyme electrode resulted in good characteristics such as a low detection limit of 2.5 mM, a wide linear range of 5 mM -0.65 mM, a short response time (within 5 s), and high sensitivity (30.64 mA mM À1 cm À2) and stability (80% remains after 30 days).

Enzyme immobilisation on electroactive nanostructured membranes (ENM): Optimised architectures for biosensing

“…As shown in Fig. 2a, CoHCF was successfully deposited onto ITO-(PVS/PAMAM-Au) 3 electrodes by potential cycling, with the cathodic and anodic peak currents increasing linearly with the number of cycles. The deposited mediator was characterised by cyclic voltammetry in 0.1 M NaPBS (pH 7.0) supporting electrolyte, the anodic and cathodic peak currents being a linear function of the square root of the scan rate, as shown in Fig.…”

“…The last step for ITO-(PVS/PAMAM-Au) 3 @CoHCF build-up was to use the system ITO-(PVS/PAMAM-Au) 3 as working electrode to electrochemically modify the PAMAM-Au surface. We previously showed that ITO-(PVS/PAMAM-Au) 3 structures are suitable for biosensors and electrocatalysis owing to their low capacitive and high Faradaic currents associated with low ohmic drop [8].…”

“…We previously showed that ITO-(PVS/PAMAM-Au) 3 structures are suitable for biosensors and electrocatalysis owing to their low capacitive and high Faradaic currents associated with low ohmic drop [8]. Electrodeposition by potential cycling of cobalt hexacyanoferrate onto ITO-(PVS/PAMAM-Au) 3 electrodes was carried out according to the optimised conditions in previous work [7,16].…”

“…In [8] and by comparing electrochemical impedance spectra of different electrodeposited metal hexacyanoferrate mediators, it was demonstrated that the charge-transfer at ITO-(PVS/PAMAMAu) 3 @Me electrodes is faster than at ITO-(PVS/PAMAM-Au) 3 , and the charge-transfer resistance using CoHCF is lower than for other hexacyanoferrates (e.g. CuHCF, FeHCF and NiHCF).…”

“…Dendrimer-encapsulated platinum nanoparticles have been used for layer-by-layer (LbL) glucose biosensor development on platinum electrodes [2] and on carbon nanotubes [3], and for a glutamate biosensor on carbon nanotubes [4], without redox mediator.…”