Single-atom nanocatalysts for biosensing application

Single-atom (SA) catalysts, as a rising star in catalytic field, have many advantages over traditional nanocatalysts. The enhanced catalytic activity, variable and simple structure as well as clear active sites of SA catalysts advance the innovation of biosensing techniques. In this review, we will provide the latest research progress of SA catalysts in biosensing field, and systematically summarize their sensing applications, especially emphasing on the biosensing strategies on the determination of disease-related biological matrices (H2O2, biological enzyme, NO, etc) and environmental pollutants (organophosphorus pesticides, heavy metal ions and volatile organic compounds). Finally, we will provide the challenges that SA catalysts still faced.

Fast Dispersive Liquid-Liquid Microextraction Based on Temperature Switching Deep Eutectic Solvent as A Green Extractant

With the development of research, it was found that the dispersive liquid-liquid microextraction (DLLME) was limited by the tedious extraction process and toxic extractant. A thermo-switchable deep eutectic solvent (DES) was applied to the DLLME as a green extractant in this paper. The DES can be dispersed and aggregated by shaking and heating in the water during the extraction process due to the surfactant and thermo-switchable properties, which shortened the extraction time as low as 5 minutes. The feasibility of the developed method was verified using 4 organophosphorus pesticides and 5 pyrethroids as targets in simulated water samples, which showed good precision (RSD%, 0.8-9.7, n=3) and low detection limit (0.16-0.81 µg L−1, S/N = 3) under the optimal extraction conditions. This method was used to detect the pesticide content in four natural rivers in Xi'an, and the recoveries of these spiked samples at three concentrations levels were among 81–113%. This is the first time to combine the toxic-free and thermo-switchable properties of DES in DLLME to proposes a simple, fast, effective, and green pretreatment method.

A comparative study: rural versus urban children as regard exposure to organophosphorus pesticides using cholinesterase enzyme activity

Background The uncontrolled long-term exposure to organophosphorus (OP) pesticides is hazardous to health especially in children. The present study aimed to determine the acetyl cholinesterase enzyme serum level in exposure and non-exposure children groups, to explore other clinical and laboratory outcomes of organophosphorus pesticides exposure on children living in rural versus urban areas, and to establish the hemotoxic alterations as a result of the exposure. A ninety clinically free children—forty-five from rural areas and forty-five children from urban areas—were assessed, and the clinical and laboratory effects of their exposure to organophosphorus pesticides were evaluated via measuring acetyl cholinesterase (AChE) enzyme activity. Results Significant differences between the two areas of residence were found in weight %, visits to the field, eating vegetables without washing, presence of insecticides at home, and previous organophosphorus pesticides toxicity of the patients and their families. Eye, respiratory, cardiac, nervous, muscle, gastrointestinal, and urinary symptoms were more common in the rural residence group which shows more exposure to pesticides. The mean level of the AChE enzyme was less in the rural residence group than the other one, and it showed significant correlations with the anemia indicating parameters. A weak positive correlation was found with platelets count. Conclusions Chronic organophosphorus toxicity that is more prevalent in rural areas may result in many transient neglected symptoms, unrevealed acetyl cholinesterase (AChE) enzyme deficiency, anemia, and thrombocytopenia. Acetyl cholinesterase enzyme serum level can be used as a screening test for organophosphorus pesticides exposure.

mRNA Transcript Analysis of Hypothesis-driven Pathways as Known Responders to Organophosphate Exposure: Rhinella Arenarum Larvae Transcriptome Study

Transcriptional analysis of the network of transcription regulators and target pathways in exposed organisms may be a hard task when their genome remains unknown. We used a whole transcriptome study on Rhinella arenarum larvae exposed to the organophosphorus pesticides azinphos-methyl and chlorpyrifos to evaluate transcriptional effects on a priori selected groups of genes. This approach allowed us to evaluate the effects on hypothesis-selected pathways such as target esterases, detoxifying enzymes, polyamine metabolism and signaling and regulatory pathways modulating them. We could then compare the responses at the transcriptional level with previously described effects at the enzymatic or metabolic levels to obtain global insight into toxicity-response mechanisms. The effects of both pesticides on the transcript levels of these pathways could be considered moderate, while the responses elicited by chlorpyrifos were more potent and earlier than those elicited by azinphos-methyl. Finally, we infer a prevailing downregulation effect of pesticides on signaling pathways and transcription factor transcripts encoding products that modulate/control the polyamine and antioxidant response pathways. We additionally tested and selected potential housekeeping genes based on those reported for other species. These results allow us to go through future confirmatory studies on pesticide gene expression modulation in toad larvae.

Oxidative Stress Induction By Pesticides May Cause Lung Cancer Incidence

Background and aims: Pesticides are nowadays known as one of the most important causes of human disorders worldwide. The aim of the present study was to investigate the role of organochlorine pesticides (OCPs) and organophosphorus pesticides (OPPs) in the development of lung cancer. Methods We determined the levels of seven derived OCP residues (α-HCH, β-HCH, γ-HCH, 2,4 DDT, 4,4 DDT, 2,4 DDE, and 4,4 DDE) and enzymatic antioxidant biomarkers including paraoxonase-1 (PON-1), erythrocyte's acetylcholinesterase (AChE), glutathione peroxidase (GPx), superoxide dismutase (SOD), catalase (CAT), and non-enzymatic antioxidant biomarkers including total antioxidant capacity (TAC), protein carbonyl (PC), malondialdehyde (MDA), and nitric oxide (NO) in the blood samples of 51 lung cancer patients and 51 healthy subjects as controls. Furthermore, the effects of OPP exposure on the development of lung cancer and oxidative stress (OS) are indirectly assessed by measuring AChE and PON-1 enzyme activities. Results The average values of all the measured OCPs were significantly higher in lung cancer patients when compared with healthy control subjects. AChE, PON-1, GPx, and CAT activity levels as well as the amounts of PC, MDA, and NO were higher in patients with lung cancer than in the control subjects, while TAC values were lower in the patients. Moreover, our data showed a significant association between OCP concentrations and OS parameters. Conclusion The results suggest that OCPs and OPPs may have a role in lung cancer incidence in southeastern Iran, and at least one of the mechanisms by which OCPs and OPPs may contribute to increasing the development of lung cancer in the studied area is through OS generation.

Ionic liquid-based effervescence-enhanced magnetic solid-phase extraction for organophosphorus pesticide detection in water samples

Herein, an ionic liquid-based effervescence-enhanced magnetic solid-phase extraction (ILE-MSPE) approach for extraction/concentration of organophosphorus pesticides in waters, which with high stability and portability for rapid sample pre-treatment in field. The...