Triboelectric Nanogenerators for Self-Powered Degradation of Chemical Pollutants

Environmental and human health is severely threatened by wastewater and air pollution, which contain a broad spectrum of organic and inorganic pollutants. Organic contaminants include dyes, volatile organic compounds (VOCs), medical waste, antibiotics, pesticides, and chemical warfare agents. Inorganic gases such as CO2, SO2, and NO x are commonly found in polluted water and air. Traditional methods for pollutant removal, such as oxidation, physicochemical techniques, biotreatment, and enzymatic decomposition, often prove to be inefficient, costly, or energy-intensive. Contemporary solutions like nanofiber-based filters, activated carbon, and plant biomass also face challenges such as generating secondary contaminants and being time-consuming. In this context, triboelectric nanogenerators (TENGs) are emerging as promising alternatives. These devices harvest ambient mechanical energy and convert it to electrical energy, enabling the self-powered degradation of chemical pollutants. This Review summarizes recent progress and challenges in using TENGs as self-powered electrochemical systems (SPECs) for pollutant degradation via photocatalysis or electrocatalysis. The working principles of TENGs are discussed, focusing on their structural flexibility, operational modes, and ability to capture energy from low-frequency mechanical stimuli. The Review concludes with perspectives and suggestions for future research in this field, hoping to inspire further interest and innovation in developing TENG-based SPECs, which represent sustainable and eco-friendly solutions for pollutant treatment.

Biosensors Based on Phenol Oxidases (Laccase, Tyrosinase, and Their Mixture) for Estimating the Total Phenolic Index in Food-Related Samples

Plant phenolic compounds demonstrate bioactive properties in vitro and/or in vivo, which creates demand for their precise determination in life sciences and industry. Measuring the concentration of individual phenolic compounds is a complex task, since approximately 9000 plant phenolic substances have been identified so far. The determination of the total phenolic content (TPC) is less laborious and is used for the qualimetric evaluation of complex multicomponent samples in routine analyses. Biosensors based on phenol oxidases (POs) have been proposed as alternative analytical devices for detecting phenolic compounds; however, their effectiveness in the analysis of food and vegetal matrices has not been addressed in detail. This review describes catalytic properties of laccase and tyrosinase and reports on the enzymatic and bienzymatic sensors based on laccase and tyrosinase for estimating the total phenolic index (TPI) in food-related samples (FRSs). The review presents the classification of biosensors, POs immobilization, the functions of nanomaterials, the biosensing catalytic cycle, interference, validation, and some other aspects related to TPI assessment. Nanomaterials are involved in the processes of immobilization, electron transfer, signal formation, and amplification, and they improve the performance of PO-based biosensors. Possible strategies for reducing interference in PO-based biosensors are discussed, namely the removal of ascorbic acid and the use of highly purified enzymes.

Laccase immobilization on the electrode surface to design a biosensor for the detection of phenolic compound such as catechol

Biosensors based on the coupling of a biological entity with a suitable transducer offer an effective route to detect phenolic compounds. Phenol and phenolic compounds are among the most toxic environmental pollutants. Laccases are multi-copper oxidases that can oxide phenol and phenolic compounds. A method is described for construction of an electrochemical biosensor to detect phenolic compounds based on covalent immobilization of laccase (Lac) onto polyaniline (PANI) electrodeposited onto a glassy carbon (GC) electrode via glutaraldehyde coupling. The modified electrode was characterized by voltammetry, Fourier transform infrared (FTIR) spectroscopy and atomic force microscopy (AFM) techniques. The results indicated that laccase was immobilized onto modified GC electrode by the covalent interaction between laccase and terminal functional groups of the glutaraldehyde. The laccase immobilized modified electrode showed a direct electron transfer reaction between laccase and the electrode. Linear range, sensitivity, and detection limit for this biosensor were 3.2 × 10(-6) to 19.6 × 10(-6)M, 706.7 mAL mol(-1), 2.07 × 10(-6)M, respectively.