An optical sensor for pesticide determination based on the autoindicating optical properties of peroxidase

Micro-Recycled Carbon Black from Waste Printer Cartridge: A Promising Magnetic Material for Single Stranded DNA Adsorption in SELEX

The increasing generation of e-waste necessitates innovative strategies for recycling and repurposing, especially for materials with high functional potential. In this study, carbon black (CB) extracted from waste printer toner cartridges is micro-recycled and oxidized into hydrophilic oxidized carbon black (OCB), transforming it into a magnetically active material for single-stranded DNA (ssDNA) adsorption in systematic evolution of ligands by exponential enrichment (SELEX). The developed OCB-SELEX approach successfully overcomes a key limitation in SELEX by enabling magnetic separation of target-bound ssDNA, eliminating nonspecific sequences efficiently. Comprehensive characterization of CB and OCB using advanced analytical techniques confirm structural, chemical, and magnetic modifications after oxidation. A fluorescence-based biosensor also fabricates using generated monocrotophos-specific aptamer (MPCB-333) and OCB demonstrates Limit of detection (LOD) of 0.72 ng mL-1 (0.72 ppb) and limit of quantification (LOQ) of 2.19 ng mL-1 (2.19 ppb) with high specificity for monocrotophos across various real samples including soil, water, and agricultural extracts. This study underscores the potential of micro-recycling waste materials into high-value functional products while advancing aptamer-based sensing platforms for environmental and agricultural monitoring.

Recent Advances on Detection of Insecticides Using Optical Sensors

Insecticides are enormously important to industry requirements and market demands in agriculture. Despite their usefulness, these insecticides can pose a dangerous risk to the safety of food, environment and all living things through various mechanisms of action. Concern about the environmental impact of repeated use of insecticides has prompted many researchers to develop rapid, economical, uncomplicated and user-friendly analytical method for the detection of insecticides. In this regards, optical sensors are considered as favorable methods for insecticides analysis because of their special features including rapid detection time, low cost, easy to use and high selectivity and sensitivity. In this review, current progresses of incorporation between recognition elements and optical sensors for insecticide detection are discussed and evaluated well, by categorizing it based on insecticide chemical classes, including the range of detection and limit of detection. Additionally, this review aims to provide powerful insights to researchers for the future development of optical sensors in the detection of insecticides.

DNA as an environmental sensor: detection and identification of pesticide contaminants in water with fluorescent nucleobases

Environmental contaminants pose a substantial health risk in many areas of the world. One of these risks is contamination of water with toxic organic species, such as herbicides and insecticides. Here we describe the discovery and properties of a set of fluorescent chemosensors that respond to micromolar concentrations of a broad range of common organic pesticides. The chemosensors are short DNA-like oligomers with fluorophores replacing DNA bases that are assembled via a DNA synthesizer. We screened a library of 1296 tetrameric compounds on polystyrene microbeads, and identified a set of chemosensor sequences that respond strongly to a set of structurally varied pesticide analytes. We show that ten chemosensors on beads can be used to detect and identify 14 different common pesticides at 100 μM, using the pattern of fluorescence intensity and wavelength changes. Limits of detection for two analytes were as low as 2 μM. The chemosensors are shown to function successfully in a practical setting, correctly identifying unknown pesticide contaminants in water from Felt Lake, California. The results establish a simple, low cost strategy for sensing environmental spills of toxic organics.