Cobalt oxide nanostructure-modified glassy carbon electrode as a highly sensitive flow injection amperometric sensor for the picomolar detection of insulin

Abstract

Glassy carbon electrode modified with electrodeposited cobalt oxide nanostructure shows an excellent electrocatalytic activity toward insulin oxidation at a wide pH range. Cyclic voltammetry, hydrodynamic amperometry, and flow injection analysis (FIA) were used for insulin determination at a picomolar and higher-concentration range. Amperometric determination of insulin at this modified electrode yielded a calibration curve with the following characteristics; linear range, 100 pM-15 nM; sensitivity of 83.9 nA nM −1 and detection limit 10 pM. FIA yielded the calibration curve with sensitivity and detection limit of 2.0 nA nM −1 and 25 pM, respectively. Furthermore, the RSD of repetitive FIA for 200 pM insulin (n=13) is 2%. In addition, the interference effect of electroactive existing species (lactic acid, cholesterol, ascorbic acid, uric acid, and glucose) was eliminated by covering the surface of the modified electrode with nafion film. Fast response time, signal stability, high sensitivity, low cost, and ease of preparation are the advantages of the proposed insulin sensor.

An electrochemical mass sensor for diagnosing diabetes in human serum

“…However, this approach has been shown to necessitate specially modied electrode surfaces to retain the insulin stability and electron transfer property with the electrode surface. [10][11][12][13][14] Mediated electrochemical oxidation of insulin in buffer by different modied electrodes consisting of metal oxide particles (osmium, ruthenium, iridium, cobalt, and nickel oxide), [14][15][16][17][18][19] carbon nanotubes, 20 ruthenium oxide-nanotubes, 21 rutheniummetallodendrimer multilayers, 22 chitosan plus MWCNTs, 23 silica gel, 24 silicon-carbide nanoparticles, 25 and Ni-powder 12 have been reported. Most of these modications yielded a detection limit in the nM range, and a few studies detected the pM concentration for mediated insulin oxidation in buffer solutions (please see ref.…”

“…Most of these modications yielded a detection limit in the nM range, and a few studies detected the pM concentration for mediated insulin oxidation in buffer solutions (please see ref. 14 for details of the electrochemical method used, detection limit and sensitivity parameters of the described electrochemical buffer insulin sensors 12,[14][15][16][17][18][19][20][21][22][23][24][25][26] ). In addition, electrochemical insulin detection under extreme acidic or basic pH conditions with enzymes or chemical labels has been shown.…”

“…In addition, electrochemical insulin detection under extreme acidic or basic pH conditions with enzymes or chemical labels has been shown. 12,14,26,27 Although, these sensor methods used good electrochemical sensing strategies, for clinical applications, measuring insulin in clinical matrices by a specic, sensitive biological assay would be appropriate. Very recently, Davis et al reported a highly sensitive impedimetric immunosensor to detect pM-sub pM insulin levels in serum.…”

TiO2-Multi Walled Carbon Nanotubes Hybrid Film Sensor for Sensing of Antiprotozoal Agent Satranidazole in Solubilzed System

“…In the present work E p linearly depends on the logarithm of the scan rate in the range of 10-100 mVs −1 according to the equation 5: E p = 0.0127 ln ν + 0.6931 (r 2 = 0.9900) [5] From eq. 4 and 5, one obtains:…”

Antifouling properties of reduced graphene oxide nanosheets for highly sensitive determination of insulin

“…However, the electrochemical detection of insulin at most of the unmodified electrodes is limited by the slow oxidation kinetics, which results in surface fouling associated with the accumulation of reaction products, and hence, decreases the selectivity and operational lifetime of the sensor. A traditional solution to these problems is to modify the electrode with appropriate compounds [2,12] or use of mediators [13] The increasing use of nanomaterials in recent years has led to substantial improvements in the efficiency of insulin electrochemical sensor. A wide range of nanomaterials, including cobalt oxide nanostructure [12], carbon nanotubes (CNTs) [5,7] nickel nanoparticles [14], guanine/nickel oxide nanoparticles [15], nickel oxide nanoparticles-MWCNTs [16], RuOx/CNTs nanocomposite [17], silicon carbide nanoparticles [8], nanocarbon black electrode surface [18], CNTs-nickel-cobaltoxide nanocomposite [10] and silica nanoparticle [11] have been used to accelerate the kinetics of insulin oxidation and to minimize the fouling of the sensor.…”