Influence of a polymer membrane on the electrochemical determination of insulin in nanomodified screen printed carbon electrodes

Abstract

Diabetes mellitus can be considered one of the most widespread diseases globally. Hence, the diabetes research is currently focused on developing an effective, low-cost sensor having high stability and suitable analytical characteristics. Screen printed carbon electrodes (SPCEs) embody ideal candidates for insulin determination due to the small area of the working electrode eliminating the solution volume required for the given purpose. Modification of SPCEs by using nanoparticles resulted in an increase of the working electrode surface area and formation of a higher number of active species. The aim of this paper is to examine the impact of a chitosan membrane on the electrochemical determination of insulin on NiO nanoparticles (NiONPs) and multi-walled nanotube (MWCNTs) modified SPCE (NiONPs/MWCNTs/SPCE). This study is primarily conceived to compare the analytical characteristics and stability of NiONPs/chitosan-MWCNTs/SPCE and NiONPs/MWCNTs/SPCE. An electrode modified with chitosan displays a wider linear range, one of 0.25 µM -5 µM (R 2 0.997); a lower limit of detection, 94 nM; a high sensitivity (0.021 µA/µM) and better stability than that of an electrode without chitosan. According to these characteristics, the polymer is considered a necessary compound of the electrochemical insulin sensor, improving the sensor's analytical characteristics.

Zn Nanoparticles Modified Screen Printed Carbon Electrode as a Promising Sensor for Insulin Determination

“…As already mentioned, all electrochemical measurements in this work were done in PBS solution, simulated the same concentration of Cl − ions and other salts presenting in a human blood. In our previous work we studied the elimination of undesirable influence of Cl − ions on electrochemical determination of insulin using chitosan membrane [35]. Figure 8 B (black line) shows the cyclic voltammogram of solution containing 2 μM insulin, 0.1 mM ascorbic acid, 0.1 mM sucrose, 5 mM glucose, and 0.1 M uric acid in 0.1 M NaOH and PBS at SPCE45 and 2 μM insulin (red line) in 0.1 M NaOH and PBS at SPCE45.…”

“…According to these results, the SPCE45 shows the best electrocatalytic activity towards insulin oxidation. In general, insulin oxidation on electrodes modified by transition metal nanoparticles such as nickel or copper occurs due to formation of high-valent catalytically active hydroxyoxides such as NiOOH in alkaline pH [35,36,37]. Nevertheless, such redox catalysis is not possible in the case of zinc, forming only a divalent cation.…”

“…ZnNPs/chitosan-MWCNTs/SPCE was prepared to study electrocatalytic activity of ZnNPs towards glucose oxidation. As was mentioned in our previous articles [24,36] MWCNTs were used because of rapid enlargement of surface area of working electrode and the role of chitosan was to stabilize the nanoparticles at the electrode surface [35]. Prepared ZnNPs/chitosan-MWCNTs/SPCE with the deposition time of Zn t = 45 s disposed of the lower LOD (0.23 μM), sufficient linear concentration range (0.5 μM to 5 μM) included the value of normal insulin concentration in blood (1.86 μM) and high sensitivity (0.19 mA/μM) in comparison to other nanomodified electrodes summarized in Table 1.…”

“…As already mentioned, all electrochemical measurements in this work were done in PBS solution, simulated the same concentration of Cl À ions and other salts presenting in a human blood. In our previous work we studied the elimination of undesirable influence of Cl À ions on electrochemical determination of insulin using chitosan membrane [35]. The main aim of this work was to test the prepared SCE45 in real sample.…”

NiO Nanoparticles for Electrochemical Insulin Detection

“…Additionally, polymer membranes such as Nafion [8,17], chitosan [18], and polyethylene glycol [19] have been widely used to prevent the fast occupation of active sites by the chloride ions in body fluids. The large benefit of the mentioned polymers is also their ability to fix nanoparticles on the electrode surface during electrochemical measurements [20].…”