Enhancing electrochemical sensing through the use of functionalized graphene composites as nanozymes.

Graphene-based nanozymes possess inherent nanomaterial properties that offer not only a simple substitute for enzymes but also a versatile platform capable of bonding with complex biochemical environments. The current review discusses the replacement of enzymes in developing biosensors with nanozymes. Functionalization of graphene-based materials with various nanoparticles can enhance their nanozymatic properties. Graphene oxide functionalization has been shown to yield graphene-based nanozymes that closely mimic several natural enzymes. This review provides an overview of the classification, current state-of-the-art development, synthesis routes, and types of functionalized graphene-based nanozymes for the design of electrochemical sensors. Furthermore, it includes a summary of the application of functionalized graphene-based nanozymes for constructing electrochemical sensors for pollutants, drugs, and various water and food samples. Challenges related to nanozymes as electrocatalytic materials are discussed, along with potential solutions and approaches for addressing these shortcomings.

Hybrid nanomaterial-based indirect electrochemical sensing of glyphosate in surface water: a promising approach for environmental monitoring.

Glyphosate (GLY), a widely utilized pesticide, poses a significant threat to human health even at minute concentrations. In this study, we propose an innovative electrochemical sensor for the indirect detection of GLY in surface water samples. The sensor incorporates a nanohybrid material composed of multi-layer graphene decorated with gold nanoparticles (AuNPs), synthesized in a single-step electrochemical process. To ensure portability and on-site measurements, the sensor is developed on a screen-printed electrode, chosen for its integration and miniaturization capabilities. The proposed sensor demonstrates remarkable sensitivity and selectivity for GLY detection in surface water samples, with an exceptional limit of detection (LOD) of 0.03 parts per billion (ppb) in both buffer and surface water matrices. Moreover, it exhibits a remarkably high sensitivity of 0.15 µA ppb-1. This electrochemical sensor offers a promising approach for accurate GLY monitoring, addressing the urgent need for reliable pesticide detection in environmental samples. The proposed sensor showed high selectivity towards GLY, when analysed in the presence of other pesticides such as phosmet, chlorpyrifos and glufosinate-ammonium. The recovery percentages of GLY from spiked surface water samples were between 93.8 and 98.9%. The study's broader implications extend to revolutionizing the way environmental chemistry addresses pesticide contamination, water quality assessment, and sustainable management of environmental pollutants. By pushing the boundaries of detection capabilities and offering practical solutions, this research contributes to the advancement of knowledge and practices that are essential for preserving and protecting our environment.

Recent Progress on Nanomaterials for NO2 Surface Acoustic Wave Sensors.

NO2 gas surface acoustic wave (SAW)sensors are under continuous development due to their high sensitivity, reliability, low cost and room temperature operation. Their integration ability with different receptor nanomaterials assures a boost in the performance of the sensors. Among the most exploited nano-materials for sensitive detection of NO2 gas molecules are carbon-based nanomaterials, metal oxide semiconductors, quantum dots, and conducting polymers. All these nanomaterials aim to create pores for NO2 gas adsorption or to enlarge the specific surface area with ultra-small nanoparticles that increase the active sites where NO2 gas molecules can diffuse. This review provides a general overview of NO2 gas SAW sensors, with a focus on the different sensors' configurations and their fabrication technology, on the nanomaterials used as sensitive NO2 layers and on the test methods for gas detection. The synthesis methods of sensing nanomaterials, their functionalization techniques, the mechanism of interaction between NO2 molecules and the sensing nanomaterials are presented and discussed.