Resonance Light Scattering Method for Study on the Interaction Between Fluorinated Surfactant Potassium Perfluorooctanesulfonate and DNA

Nano-enabled sensing of per-/poly-fluoroalkyl substances (PFAS) from aqueous systems - A review

Per-/poly-fluoroalkyl substances (PFAS) are an emerging class of environmental contaminants used as an additive across various commodity and fire-retardant products, for their unique thermo-chemical stability, and to alter their surface properties towards selective liquid repellence. These properties also make PFAS highly persistent and mobile across various environmental compartments, leading to bioaccumulation, and causing acute ecotoxicity at all trophic levels particularly to human populations, thus increasing the need for monitoring at their repositories or usage sites. In this review, current nano-enabled methods towards PFAS sensing and its monitoring in wastewater are critically discussed and benchmarked against conventional detection methods. The discussion correlates the materials' properties to the sensitivity, responsiveness, and reproducibility of the sensing performance for nano-enabled sensors in currently explored electrochemical, spectrophotometric, colorimetric, optical, fluorometric, and biochemical with limits of detection of 1.02 × 10^-6 μg/L, 2.8 μg/L, 1 μg/L, 0.13 μg/L, 6.0 × 10^-5 μg/L, and 4.141 × 10^-7 μg/L respectively. The cost-effectiveness of sensing platforms plays an important role in the on-site analysis success and upscalability of nano-enabled sensors. Environmental monitoring of PFAS is a step closer to PFAS remediation. Electrochemical and biosensing methods have proven to be the most reliable tools for future PFAS sensing endeavors with very promising detection limits in an aqueous matrix, short detection times, and ease of fabrication.

Study on the binding interaction between perfluoroalkyl acids and DNA

Perfluoroalkyl acids (PFAAs) are carcinogens, and elucidating their DNA binding properties is crucial for understanding PFAA genotoxicity. We have investigated the binding mode and affinity of five PFAAs to seven DNA molecules using fluorescence displacement and molecular docking analysis. DNA conformational changes upon PFAA binding were also examined by circular dichroism (CD). The data revealed that DNA intercalation was the dominant interaction mode of the PFAAs; however, these molecules also bound to grooves. The dissociation constants for the PFAAs ranged between 0.11 and 1,217.14 μM, and between 3.46 and 2,141.21 μM for DNA intercalation and groove binding, respectively. PFAAs that contain longer carbon chains had stronger DNA intercalation affinities. Binding to DNA was stronger for perfluoroalkyl sulfonates than for perfluorcarboxyl acids that contain the same number of carbons. This observation is postulated to arise from the presence of more fluorine and oxygen atoms in perfluoroalkyl sulfonates acting as hydrogen bond donors that facilitate stronger DNA intercalation. The binding of the PFAAs to DNA showed some CT-DNA sequence selectivity. Molecular docking analysis confirmed the DNA binding mode and affinities of the PFAAs. CD analysis revealed that the PFAAs weakened DNA base stacking and loosened DNA helicity. The present study has improved our understanding of the formation of PFAA-DNA adducts.