Insulin sensor based on nanoparticle-decorated multiwalled carbon nanotubes modified electrodes

Abstract

22Insulin sensors based on glassy carbon electrodes modified with nafion-multiwalled carbon 23 nanotubes decorated with nickel hydroxide nanoparticles (Ni(OH) 2 NPs/Nafion-24 MWCNTs/GC), were prepared by electrochemical deposition of Ni(OH) 2 NPs from a 25 dinuclear paddle-wheel Ni monothiocarboxylate complex on the MWCNTs/GC surface. 26The size and distribution of the Ni(OH) 2 NPs/Nafion-MWCNTs were characterized by 27 transmission electron microscopy (TEM). The results show that Ni(OH) 2 nanoparticles 28 were electrodeposited on the surface of carbon nanotubes. Moreover, the electrochemical 29 behavior of the modified electrodes in aqueous alkaline solutions of insulin was studied by 30 cyclic voltammetry and chronoamperometry. It was found that the as-prepared 31 nanoparticles have excellent electrocatalytic activity towards insulin oxidation due to their 32 special properties, reducing the overpotential and improving the electrochemical behavior, 33 compared to the bare GC electrode. Amperometry was used to evaluate the analytical 34 performance of modified electrode in the determination of insulin. Excellent analytical 35 features, including high sensitivity (5.0 A mol cm -2 μM -1 ), low detection limit (85 nM) and 36 wide dynamic range (up to 10.00 µM), were achieved under optimum conditions. 37 Moreover, these insulin sensors show good repeatability and a high stability after 38 successive potential cycling. Common substances such as ascorbic acid, uric acid and 39 acetaminophen do not interfere. Finally, the developed sensors have been applied to the 40 determination of insulin in pharmaceuticals and in human plasma. Efficient recoveries for 41 pharmaceuticals and human plasma demonstrate that the proposed methodology can be 42 satisfactorily applied to these types of samples.43 Page 3 of 37 A c c e p t e d M a n u s c r i p t 3 44 Keywords 45 Dinickel complexes, paddle-wheel complexes, nickel hydroxide nanoparticles, insulin 46 electrocatalysis.

Comparison of Insulin Determination on NiNPs/chitosan‐ MWCNTs and NiONPs/chitosan‐MWCNTs Modified Pencil Graphite Electrode

“…PGEs have several advantages in comparison to other carbon-based electrodes, including, very low cost, simple modification, widespread availability [25] and well defined surface area [11]. MWCNTs are also known as an excellent option to enlarge electrode surface area, create more active sites for insulin oxidation, increase voltammetric current and decrease overpotential [27]. Therefore, various materials for electrode modification such as multiwalled carbon nanotubes (MWCNTs), metal nanoparticles, metal oxide nanoparticles or combination of these materials have been studied.…”

“…Nickel based nanomaterials have become an intensively studied material not only because of their low cost in comparison with Ag, Co, Pd or Pt nanoparticles but also because they possess some desirable characteristics such as high electrical conductivity and good electrocatalytic activity [34]. Particularly, large surface area and excellent magnetic properties are the greatest advantages of synthetized nanoparticles [27]. Particularly, large surface area and excellent magnetic properties are the greatest advantages of synthetized nanoparticles [27].…”

“…MWCNTs are frequently used in electrochemical determination of insulin for electrode modifications due to their mechanical stability and fast electron transport. MWCNTs are also known as an excellent option to enlarge electrode surface area, create more active sites for insulin oxidation, increase voltammetric current and decrease overpotential [27]. It is also well known that large surface area of MWCNTs combined with metal nanoparticles or metal oxide nanoparticles can improve the performance of the final electrode material [28,29].…”

“…It is known that the chemical and physical properties of the NiONPs and NiNPs are quite different from bulk Ni and NiO crystals. Particularly, large surface area and excellent magnetic properties are the greatest advantages of synthetized nanoparticles [27]. In addition, it has been revealed that many nickel-based materials exhibit excellent electrocatalytic activity towards the oxidation of a wide range of small compounds, like insulin or glucose in alkaline media [35].…”

A Review on the Effects of Introducing CNTs in the Modification Process of Electrochemical Sensors

“…Lorenzo and coworkers introduced a GCE modified with nafion/MWCNTs/ Ni(OH) 2 nanoparticles which combines the advantages of high conductivity, high specific area, and antifouling properties of MWCNs with high electrocatalytic activity of Ni(OH) 2 nanoparticlesto produce an insulin sensor 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 with reduced overpotential and improved electrochemical behavior [45]. Lorenzo and coworkers introduced a GCE modified with nafion/MWCNTs/ Ni(OH) 2 nanoparticles which combines the advantages of high conductivity, high specific area, and antifouling properties of MWCNs with high electrocatalytic activity of Ni(OH) 2 nanoparticlesto produce an insulin sensor 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 with reduced overpotential and improved electrochemical behavior [45].…”