Electrochemical Enzyme Biosensors Revisited: Old Solutions for New Problems

Abstract

Worldwide legislation is driving the development of novel and highly efficient analytical tools for assessing the composition of every material that interacts with Consumers or Nature. The biosensor technology is one of the most active R&D domains of Analytical Sciences focused on the challenge of taking analytical chemistry to the field. Electrochemical biosensors based on redox enzymes, in particular, are highly appealing due to their usual quick response, high selectivity and sensitivity, low cost and portable dimensions. This review paper aims to provide an overview of the most important advances made in the field since the proposal of the first biosensor, the well-known hand-held glucose meter. The first section addresses the current needs and challenges for novel analytical tools, followed by a brief description of the different components and configurations of biosensing devices, and the fundamentals of enzyme kinetics and amperometry. The following sections emphasize on enzyme-based amperometric biosensors and the different stages of their development.

Microorganisms and Their Metabolic Capabilities in the Context of the Biogeochemical Nitrogen Cycle at Extreme Environments

“…The immobilization of the enzymes improves the stability and half-life of the enzymes, making the system robust and sensible. Other aspects, such as quick response, high selectivity, and sensitivity, low cost, and portable dimensions, are also inherent to electrochemical biosensors based on redox enzymes involved in N-cycle [181][182][183]. Apart from the enzymes catalyzing the four main reactions of denitrification, other accessory proteins involved in denitrification, such as cytochrome c, have also been tested as part of a biosensor to monitor nitrate, hydrogen peroxide or superoxide [184].…”

Enzyme-Based Electrochemical Biosensors for Microfluidic Platforms to Detect Pharmaceutical Residues in Wastewater

“…Enzyme-based sensors are highly specific catalytic biosensors where the recognition elements are extremely selective enzyme molecules immobilized on transducing surfaces known as electrodes [10,14,15]. Under the presence of a suitable substrate, the enzymes catalyze electrochemical reactions involving electroactive products or measurable electric changes on the transducer and the sample [15,16].…”

“…The concentration or redox potential of an analyte in a sample can be determined via measurements of potential, charge, or current. The devices to conduct these measurements apply potentiometric, impedimetric and amperometric techniques, respectively [14,16,17].…”

“…The amperometric methods are the most suitable to perform the transduction of the enzymatic response into a quantifiable signal [14]. In this case, the number of species involved in the redox process is related to the electrons generated when a fixed potential is applied between two electrodes, which can be ultimately detected as current change.…”

Dextran Aldehyde in Biocatalysis: More Than a Mere Immobilization System

“…When employed as industrial biocatalysts, the desired enzymatic capability may not be always the same; for instance, chemo-and regio-selectivity will be always necessary, while enzyme stereoselectivity would be demanded in the resolution of racemic mixtures or in the desymmetrization of prochiral compounds. Enzyme specificity also makes these biocatalysts very suitable in analytical chemistry [26][27][28][29]. Thus, many enzymatic biosensors have been developed to determine the concentration of one specific component inside a very complex mixture (e.g., glucose in blood [30,31]).…”