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While highly reactive cerium oxide nanoparticles (CeO₂ NPs) are widely used in industry, their transport in aquatic systems is not well understood. To fill this knowledge gap, the interactions of CeO₂ NPs with arsenite (As³⁺), a toxic metalloid and potential co-present contaminant, were investigated with respect to CeO₂ NP colloidal stability, dissolution, and surface redox reactions. Arsenite showed distinctive effects at different concentrations, with a high As³⁺ concentration (10⁻⁴ M) inducing 90% of CeO₂ NPs to settle from solution after 8 hours, while lower As³⁺ concentrations (10⁻⁵ or 10⁻⁶ M) led to only 20% of CeO₂ NPs settling. The dissolution of NPs was most significant in the 10⁻⁵ M As³⁺ system owing to a lesser extent of aggregation, exposing more CeO₂ surface for dissolution. In the three As³⁺ concentration systems, >97% of aqueous arsenic remained as As³⁺ over 6 hours. On the NP surface, adsorbed As^(III) was oxidized to As^V, resulting in 58–70% of the adsorbed arsenic remaining as As^(III). Simultaneously Ce^(IV) was reduced to Ce^(III), increasing Ce^(III) on the CeO₂ NP surface from 17% (without arsenite) to 21–25% (with arsenite). Further mechanistic analyses revealed that the adsorption of arsenite was the main contributor to neutralizing the CeO₂ NP surface potential, enhancing particle sedimentation. These findings suggest that the fate and transport of CeO₂ NPs in our experimental systems are strongly affected by arsenite concentration and its adsorption on NPs. The results also highlight the importance of the interplay between NP aggregation, oxidation, and dissolution in predicting the behaviors of CeO₂ NPs and associated toxic elements in aquatic systems.

In this work, we introduce an asymmetric membrane as a simple and robust nanofluidic platform for digital detection of single pathogenic bacteria directly in 10 mL of unprocessed environmental water samples. The asymmetric membrane, consisting of uniform micropores on one side and a high density of vertically aligned nanochannels on the other side, was prepared within 1 min by a facile method. The single membrane covers all the processing steps from sample concentration, purification, and partition to final digital loop-mediated isothermal amplification (LAMP). By simple filtration, bacteria were enriched and partitioned inside the micropores, while inhibitors typically found in the environmental samples ( i.e., proteins, heavy metals, and organics) were washed away through the nanochannels. Meanwhile, large particles, indigenous plankton, and positively charged pollutants in the samples were excluded by using a sacrificial membrane stacked on top. After initial filtration, modified LAMP reagents, including NaF and lysozyme, were loaded onto the membrane. Each pore in the asymmetric membrane functioned as an individual nanoreactor for selective, rapid, and efficient isothermal amplification of single bacteria, generating a bright fluorescence for direct counting. Even though high levels of inhibitors were present, absolute quantification of Escherichia coli and Salmonella directly in an unprocessed environmental sample (seawater and pond water) was achieved within 1 h, with sensitivity down to single cell and a dynamic range of 0.3-10000 cells/mL. The simple and low-cost analysis platform described herein has an enormous potential for the detection of pathogens, exosomes, stem cells, and viruses as well as single-cell heterogeneity analysis in environmental, food, and clinical research.

This study was aimed to assess serum microRNA-30d-5p (miR-30d-5p) expression in patients with esophageal squamous cell carcinoma before and after operation, exploring its associations with clinical pathological parameters. A total of 30 esophageal cancer patients who underwent radical resection and were pathologically confirmed with esophageal squamous cell carcinoma in the First Affiliated Hospital of Anhui Medical University, from April to May in 2013, were enrolled, alongside 19 healthy controls. The expression levels of miRNA in serum from patients with esophageal squamous cell carcinoma before and after operation were assessed by microarrays and real-time PCR (RT-PCR). The associations of miR-30d-5p expression with clinical pathological parameters were determined. Serum hsa-miR-30d-5p levels in patients with esophageal squamous cell carcinoma (study group) were significantly associated with the tumor depth of invasion, lymph node metastasis, tumor location and length, histopathological type and degree of differentiation, as well as history of smoking and drinking (P