Recent Advances in Electrochemical Sensing of Hydrogen Peroxide (H2O2) Released from Cancer Cells

Abstract

Cancer is by far the most common cause of death worldwide. There are more than 200 types of cancer known hitherto depending upon the origin and type. Early diagnosis of cancer provides better disease prognosis and the best chance for a cure. This fact prompts world-leading scientists and clinicians to develop techniques for the early detection of cancer. Thus, less morbidity and lower mortality rates are envisioned. The latest advancements in the diagnosis of cancer utilizing nanotechnology have manifested encouraging results. Cancerous cells are well known for their substantial amounts of hydrogen peroxide (H₂O₂). The common methods for the detection of H₂O₂ include colorimetry, titration, chromatography, spectrophotometry, fluorimetry, and chemiluminescence. These methods commonly lack selectivity, sensitivity, and reproducibility and have prolonged analytical time. New biosensors are reported to circumvent these obstacles. The production of detectable amounts of H₂O₂ by cancerous cells has promoted the use of bio- and electrochemical sensors because of their high sensitivity, selectivity, robustness, and miniaturized point-of-care cancer diagnostics. Thus, this review will emphasize the principles, analytical parameters, advantages, and disadvantages of the latest electrochemical biosensors in the detection of H₂O₂. It will provide a summary of the latest technological advancements of biosensors based on potentiometric, impedimetric, amperometric, and voltammetric H₂O₂ detection. Moreover, it will critically describe the classification of biosensors based on the material, nature, conjugation, and carbon-nanocomposite electrodes for rapid and effective detection of H₂O₂, which can be useful in the early detection of cancerous cells.

Keywords: H2O2; analytical methods; biosensors; carbon materials; electrochemical sensing; nanomaterial.

Figure 1

Distinct strategies for the electrochemical detection of H₂O₂ including Cyto-biosensors, Immuno-biosensors, Enzymatic and non-enzymatic biosensors. Figure reproduced with permission from [46]. Copyright 2014. American Chemical Society (Washington, DC, USA).

Figure 2

Mechanism of the chemiluminescent material for the detection of H₂O₂ released in cancer cells. Excitation and de-excitation of chemiluminescence materials can be seen during chemical reaction.

Figure 3

Analysis of HyPer fluorescence in K562 cells exposed to extracellular H₂O₂. (a) Scheme demonstrating the changes in the excitation spectrum of HyPer upon oxidation. (b) Flow cytometry histograms of K562 cells measured after two-minute exposure to different concentrations of H₂O₂. Reproduced with permission from [127]. Copyright 2019, Science Direct (Amsterdam, The Netherlands).

Figure 4

Different types of carbon-based materials, i.e., (a) Graphene, (b) Carbon nanotube, and (c) reduced grapheme oxide, used in electrochemical sensing of H₂O₂.

Figure 5

Mechanism of the synthesis of the graphene enzyme composite for the electrochemical sensing of H₂O₂. Reproduced with permission from [216]. Copyright 2015, Science Direct.

Figure 6

Enzyme-loaded CNTs for the detection of H₂O₂ in living cells. Reproduced with permission from [336]. Copyright 2019, Elsevier Ltd (Amsterdam, The Netherlands).

Figure 7

Mechanism of metal nanoparticle loaded CNTs for real-time analyses of H₂O₂ secreted from live cells. Reproduced with permission from [324], Copyright 2016 Spinger Ltd (Berlin/Heidelberg, Germany).