Analytical performance of functional nanostructured biointerfaces for sensing phenolic compounds

Nanomaterial-based electrochemical enzymatic biosensors for recognizing phenolic compounds in aqueous effluents

With the rapid development of industrial society, phenolic pollutants already identified in water are severe threats to human health. Traditional detection techniques like chromatography are poor in the ability of cost-effectiveness and on-site detection. In recent years, electrochemical enzymatic biosensors have attracted increasing attention for use in the recognition of phenolic compounds, which is considered an effective strategy for the product transfer of portable analytical devices. Although electrochemical enzymatic biosensors provide a fast, accurate on-site detection technique, the difficulties of enzyme deactivation, poor stability and low sensitivity remain to be solved. Thus, effective immobilization methods of enzymes and nanomaterials with excellent properties have been extensively researched to obtain a high-sensitivity and high-stability biosensing platform. Simultaneous detection of multiple phenols may become the focus of further research. In this review, we provide an overview of recent progress toward electrochemical enzymatic biosensors for the detection of phenolic compounds, including enzyme immobilization approaches and advanced nanomaterials, especially nanocomposites with attractive properties such as good conductivity, high specific surface area, and porous structure. We will comprehensively discuss the features and mechanisms of the main enzymes adopted in the construction of different phenolic biosensors, as well as traditional methods (e.g., adsorption, covalent bonding, entrapment, encapsulation, cross-linking) of enzyme immobilization. The most effective method is based on the properties of enzymes, supports and application objective because there is no one-size-fits-all method of enzymatic immobilization. The emphasis will be given to various advanced nanomaterials, including their special nanostructures, preparation methods and performance. Finally, the main challenges in future research on electrochemical phenolic biosensors will be discussed to provide further perspectives for practical applications in dynamic and on-site monitoring. We believe this review will deliver an important inspiration for the construction of novel and high-performance electrochemical biosensors from enzyme selection to nanomaterial design for the detection of various hazardous materials. We believe this review will deliver an important inspiration on the construction of novel and high-performance electrochemical biosensors from the enzyme selection to the nanomaterial design for detections of various hazardous materials.

A Ready-to-Use Metal-Supported Bilayer Lipid Membrane Biosensor for the Detection of Phenol in Water

This work presents a novel metal-supported bilayer lipid membrane (BLM) biosensor built on tyrosinase to quantitate phenol. The detection strategy is based on the enzyme-analyte initial association and not the commonly adopted monitoring of the redox cascade reactions; such an approach has not been proposed in the literature to date and offers many advantages for environmental monitoring with regard to sensitivity, selectivity, reliability and assay simplicity. The phenol sensor developed herein showed good analytical and operational characteristics: the detection limit (signal-to-noise ratio = 3) was 1.24 pg/mL and the sensitivity was 33.45 nA per pg/mL phenol concentration. The shelf life of the tyrosinase sensor was 12 h and the lifetime (in consecutive assays) was 8 h. The sensor was reversible with bathing at pH 8.5 and could be used for eight assay runs in consecutive assays. The validation in real water samples showed that the sensor could reliably detect 2.5 ppb phenol in tap and river water and 6.1 ppb phenol in lake water, without sample pretreatment. The prospects and applicability of the proposed biosensor and the underlying technology are also discussed.