Carbon Nanotube‐Based Electrochemical Sensors: Principles  and  Applications  in  Biomedical  Systems

Abstract

Carbon nanotubes (CNTs) have received considerable attention in the field of electrochemical sensing, due to their unique structural, electronic and chemical properties, for instance, unique tubular nanostructure, large specific surface, excellent conductivity, modifiable sidewall, high conductivity, good biocompatibility, and so on. Here, we tried to give a comprehensive review on some important aspects of the applications of CNT-based electrochemical sensors in biomedical systems, including the electrochemical nature of CNTs, the methods for dispersing CNTs in solution, the approaches to the immobilization of functional CNT sensing films on electrodes, and the extensive biomedical applications of the CNT-based electrochemical sensors. In the last section, we mainly focused on the applications of CNT-based electrochemical sensors in the analysis of various biological substances and drugs, the methods for constructing enzyme-based electrochemical biosensors and the direct electron transfer of redox proteins on CNTs. Because several crucial factors (e.g., the surface properties of carbon nanotubes, the methods for constructing carbon nanotube electrodes and the manners for electrochemical sensing applications) predominated the analytical performances of carbon nanotube electrodes, a systematical comprehension of the related knowledge was essential to the acquaintance, mastery and development of carbon nanotube-based electrochemical sensors.

Carbon Nanotube-Based Electrochemical Sensor for the Determination of Anthraquinone Hair Dyes in Wastewaters

“…The peak current ratio Ipa/Ipc was 0.96, and the peak to peak separation, ΔEp = Epa − Epc, was 30 mV. The results indicated that CNTMEs are an excellent platform for constructing an electrochemical sensor for dyes bearing anthraquinone groups and improve the reversibility of the electron transfer process due to their electrocatalytic activities [29] toward these species, enhancing the current yielded and reducing peak-to-peak separations in comparison with the bare electrode. In order to improve the response of the CNTME, the same electrode was subjected to scans in acid medium in order to remove material from the organic solvent (DMF) on its surface, thus increasing its area.…”

“…The great versatility of multiwalled carbon nanotubes as electrode modifiers has attracted attention [28][29][30][31][32][33][34][35][36]. They are fulfilling the growing demand for highly sensitive, reliable and inexpensive sensors for the measurement of hazardous compounds in environmental samples, usually in highly diluted forms.…”

“…The main advantages of this kind of electrode system are associated with their modest cost and wide possibilities for surface modifications. The ability to determine low levels of multiple kinds of analytes has been attributed mainly to electrocatalytic or adsorption effects due to their unique tubular nanostructure, large specific surface area, excellent conductivity, modifiable sidewalls, high conductivity and good biocompatibility [28,29,32,36].…”

Enzyme-free monitoring of glucose utilization in stimulated macrophages using carbon nanotube-decorated electrochemical sensor

“…The appearance of the glucose oxidation peak indicates that the mildly alkaline conditions provided by the phosphate buffered saline is sufficient for the oxidation of glucose to gluconic acid catalyzed by the CNT-modified surface that also captures the resultant electron transfer efficiently. Though the exact mechanism for the electrocatalytic behavior of MWCNTs has not yet been deciphered, it is believed that a combination of defect sites at the cap and the presence of oxygen-containing functional groups contribute to the electrocatalytic effect of MWCNTs (Hu and Hu 2009). The alkaline medium has been reported to activate the surface functionalities in MWCNTs (Ye et al 2004).…”

A Biocompatible Nanocomposite for Glucose Sensing

“…They have unique characteristics such as high conductivity, nonvolatile nature, low toxicity, large electrochemical window, strong electrostatic field, and good electrochemical stability [4]. Because of special properties of RTILs, their applications are increasing in different fields [5] especially for improvement in enzyme electron transfer rate and stability [4,6,7].…”