Recent Advances in Potentiometric Biosensing

Abstract

Potentiometric biosensors are incredibly versatile tools with budding uses in industry, security, environmental safety, and human health. This mini-review on recent (2018-2020) advances in the field of potentiometric biosensors is intended to give a general overview of the main types of potentiometric biosensors for novices while still providing a brief but thorough summary of the novel advances and trends for experienced practitioners. These trends include the incorporation of nanomaterials, graphene, and novel immobilization materials, as well as a strong push towards miniaturized, flexible, and self-powered devices for in-field or at-home use.

Keywords: Biofuel cells; Biosensors; Field effect transistors; Flexible sensors; Potentiometry.

Figure 1.

Schematic of a conventional ISE for analysis of solution pH.

Figure 2.

Schematic of a a) field effect transistor, where changes in the gate voltage cause either holes or electron carries to move between the source and the drain, resulting in a change to the device’s conductance and a b) Bio-FET, where binding of the analyte to the biorecognition element leads to a change in charge distribution of the semiconducting layer, driving a change in overall conductance of the device.

Figure 3.

Schematic of a biofuel cell, where the energy to power the lightbulb is made by the reactions occurring at the cathode-glucose oxidase turning over glucose and releasing an electrode into the anode-and laccase using that electron to turn dissolved oxygen into water.

Figure 4.

Summary of the types of potentiometric biosensors, with an example schematic of each type: Ion-selective electrode for the detection of recombinant human myelin basic protein [9], a modified screen-printed electrode for the simultaneous detection of Hg²⁺, Cd²⁺, and As³⁺ [23], a graphene-based field effect transistor for the detection of neuropeptide Y [34], a self-powered biosensor for the detection of a single nucleotide polymorphism [38], and a flexible, fabric-based biosensor for the detection of glucose [32].