New insight on biological interaction analysis: new nanocrystalline mixed metal oxide SPME fiber for GC-FID analysis of BTEX and its application in human hemoglobin-benzene interaction studies

Quinoline Bridging Hyperconjugated Covalent Organic Framework as Solid-Phase Microextraction Coating for Ultrasensitive Determination of Phthalate Esters in Water Samples

Phthalate esters (PAEs) are widely distributed in the environment, and this has caused serious health and safety concerns. Development of rapid and ultrasensitive identification and analysis methods for phthalate esters is urgent and highly desirable. In this work, a novel nitrogen-rich covalent organic framework (N-TTI) derived quinoline bridging covalent organic framework (N-QTTI) was fabricated and used as a solid-phase microextraction (SPME) coating for the ultrasensitive determination of phthalate esters in water samples. The physical and chemical properties of N-QTTI were investigated sufficiently. The N-QTTI-coated fiber demonstrates a superior enrichment performance than either the N-TTI-coated fiber or commercial fibers under the optimized SPME conditions. For the first time, we propose a semi-immersion strategy for the extraction of PAEs from water samples based on N-QTTI-coated SPME fibers. Combined with gas chromatography-mass spectrometry (GC-MS), the developed method N-QTTI-SPME-GC-MS exhibits a wide linear range with a satisfactory linearity (R2 ≥ 0.995). The limits of detection (LOD, S/N = 3) and the limits of quantification (LOQs, S/N = 10) were 0.17-1.70 and 0.57-5.60 ng L-1, respectively. The repeatability of the new method was examined using relative standard deviations (RSDs) between intraday and interday data, which were 0.38-7.98% and 1.22-6.60%, respectively. The spiked recoveries at three levels of 10, 100, and 1000 ng L-1 were in the range of 90.0-106.2% with RSDs of less than 7.48%. The enrichment factors ranged from 291 to 17180. When compared to previously published works, the LODs of the newly established method were improved 5-5400 times, and the enrichment factors were increased by at least 8 times. The absorption mechanism was investigated by X-ray photoelectron spectroscopy and noncovalent interaction force analysis. The technique was successfully employed for detecting PAEs in water samples.

Spectroscopic investigation on molecular aspects and structural and functional effects of tetraethyl pyrophosphate organophosphorus insecticide interaction with adult human hemoglobin

Organophosphates are extremely toxic compounds that use extensively in agriculture and household as insecticides. However, their binding mechanism to bio-macromolecules especially blood proteins is not clearly understood. In this research, various spectroscopic techniques utilized to analyze the effect of Tetraethyl Pyrophosphate (TEPP), as an organophosphorus insecticide, on the structure, function, stability, and aggregation of adult human hemoglobin and also hemolysis potential of the TEPP on red blood cells (RBCs) examined. Molecular docking was used for TEPP binding to human Hemoglobin (Hb), too. The results demonstrated that the TEPP insecticide has the potential for lysing RBCs. UV-Vis experiment indicated that globin part and heme group influenced by TEPP. Oxygen affinity measurements revealed the formation of deoxy-Hb and met-Hb, also decreased in oxygen affinity of Hb upon interaction with TEPP that is due to heme destruction. Fluorescence spectroscopy confirmed the production of heme degradation species after interaction of Hb with TEPP, which is inconsistent with oxygen affinity measurements. Thermal and aggregation studies indicated that TEPP induced aggregation of Hb in a concentration manner and T_m of protein reduced to lower temperatures. Docking's study also showed that TEPP interacts with Hb through hydrophobic interactions, which confirms UV-Vis results. ATR-FTIR study also revealed that TEPP can induce changes in the alpha helix element of Hb's secondary structure. Totally, Experimental and theoretical results indicate that tetraethyl pyrophosphate has unfavorable effects on hemoglobin structure and function.Communicated by Ramaswamy H. Sarma.

Effect of low-level laser irradiation on cytotoxicity of benzene in human normal fibroblast cells

Benzene is volatile organic hydrocarbon which is widely used in a wide range of industries. Studies have shown that exposure to benzene consequences serious health risks for human. Understanding the effect and risks of environmental hazard materials in the laser therapy of skin is interesting which can show useful or harmful role of these effects in therapies. In this study, the effect of low-level laser therapy was investigated on benzene-induced cytotoxicity on human skin fibroblast cells (HU02). Human skin fibroblast cells (HU02) were exposed to various concentrations of benzene (0-100 μg/mL) and incubated for 2 h. Then the effect of low-level laser therapy (LLLT) at 660-nm wavelength with 3 J/cm² energy for 90 s was investigated on the viability of the cells exposed to benzene using MTT assay and inverted light microscope. The effect of low-level laser therapy on the viability of the cells was positive at concentrations 0-15 μg/mL but negative at higher concentrations than 15 μg/mL. Low-level laser therapy in low concentrations of benzene decreases the cytotoxicity caused by benzene and maintains cell viability. At high concentrations and in the presence of low-level laser therapy, the cell viability decreased compared to dark experiment. The morphology study of the cells using inverted light microscopy has confirmed the MTT results.