α-Cyclodextrin functionalized silver nanoparticles as colorimetric sensor for micro extraction and trace level detection of chlorpyrifos pesticide in fruits and vegetables

We report a novel UV-Vis spectrophotometry combined with micro Soxhlet extraction method for the detection of CPS pesticide in fruits and vegetables based on alpha-cyclodextrin capped silver nanoparticles (AgNPs/α-CD). Recently, CPS pesticide has been used as a disinfectant in post-harvesting agriculture to prevent or inhibition of recent outbreaks (COVID-19) with pathogens contamination resulting in an increased concentration of pesticides in the environment. Therefore, we developed an AgNPs/α-CD as a chemical sensor for the detection of CPS loaded on agricultural products. The sensing mechanism for the detection of CPS pesticide is based on the change in color of the AgNPs/α-CD from yellow to red followed by the redshift of the LSPR absorption band (410/570nm) in the UV-Vis region after the addition of the analyte into the NPs solution. The changes of color and LSPR band shifting of AgNPs are observed only in CPS pesticides due to the H-bonding and non-covalent interactions of oxygen moieties with AgNPs/α-CD. Limit of detection (LOD) and limit of quantification (LOQ) in the region of 4.0 and 13.0 ngmL-1 have been achieved for CPS pesticide using AgNPs/α-CD, respectively. These data establish the potential for this sensor for the use CPS pesticide analysis at trace levels.

In vitro and clinical studies on the efficacy of alpha-cyclodextrin and hydroxytyrosol against SARS-CoV-2 infection

OBJECTIVE: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a new coronavirus responsible for the current pandemic of coronavirus disease 2019 (COVID-19). This virus attacks cells of the airway epithelium by binding transmembrane angiotensin-converting enzyme 2 (ACE2). Hydroxytyrosol has anti-viral properties. Alpha-cyclodextrin can deplete sphingolipids and phospholipids from cell membranes. The aim of the present experimental study was to evaluate the efficacy of alpha-cyclodextrin and hydroxytyrosol in improving defenses against SARS-CoV-2 infection in in vitro cell models and humans. PATIENTS AND METHODS: For in vitro experiments on Vero E6 cells, RNA for RT-qPCR analysis was extracted from Caco2 and human fibroblast cell lines. For study in humans, the treatment group consisted of 149 healthy volunteers in Northern Cyprus, considered at higher risk of SARS-CoV-2 infection than the general population. The volunteers used nasal spray containing alpha-cyclodextrin and hydroxytyrosol for 4 weeks. The control group consisted of 76 healthy volunteers who did not use the spray. RESULTS: RT-qPCR experiments on targeted genes involved in endocytosis showed a reduction in gene expression, whereas cytotoxicity and cytoprotective tests showed that the compounds exerted a protective effect against SARS-CoV-2 infection at non-cytotoxic concentrations. None of the volunteers became positive to SARS-CoV-2 RT-qPCR assay during the 30 days of treatment. CONCLUSIONS: Treatment with alpha-cyclodextrin and hydroxytyrosol nasal spray improved defenses against SARS-CoV-2 infection and reduced synthesis of viral particles.