Suspect screening-data independent analysis workflow for the identification of arsenolipids in marine standard reference materials.

There has been limited research into arsenolipid toxicological risks and health-related outcomes due to challenges with their separation, identification, and quantification within complex biological matrices (e.g., fish, seaweed).

Prediction of Nanoparticle Photoreactivity in Mixtures of Surface Foulants Requires Kinetic (Non-equilibrium) Adsorption Considerations.

The adsorption of foulants on photocatalytic nanoparticles can suppress their reactivity in water treatment applications by scavenging reactive species at the photocatalyst surface, screening light, or competing for surface sites. These inhibitory effects are commonly modeled using the Langmuir-Hinshelwood model, assuming that adsorbed layer compositions follow Langmuirian (equilibrium) competitive adsorption. However, this assumption has not been evaluated in complex mixtures of foulants.

Comparative study on effects of pH, electrolytes, and humic acid on the stability of acetic and polyacrylic acid coated magnetite nanoparticles.

The poor colloidal stability of magnetite nanoparticles (MNPs) limits their mobility and application, so various organic coatings (OCs) were applied to MNPs. Here, a comparative study on the colloidal stability of MNPs coated with acetic (HAc) and polyacrylic acids (PAA) was conducted under varied pH (5.0-9.

Natural organic matter flocculation behavior controls lead phosphate particle aggregation by mono- and divalent cations.

Phosphate addition is commonly applied to remediate lead contaminated sites via the formation of lead phosphate particles with low solubility. However, the effects of natural organic matter (NOM) with different properties, as well as the contributions of specific interactions (particle-particle, particle-NOM, and NOM-NOM) in enhanced stabilization or flocculation of the particles, are not currently well understood. This study investigates the influence of two aquatic NOM and two soil or coal humic acid (HA) extracts on the aggregation behavior of lead phosphate particles and explores the controlling mechanisms.

Distinguishing nanoparticle drug release mechanisms by asymmetric flow field-flow fractionation.

This research demonstrates the development, application, and mechanistic value of a multi-detector asymmetric flow field-flow fractionation (AF4) approach to acquire size-resolved drug loading and release profiles from polymeric nanoparticles (NPs). AF4 was hyphenated with multiple online detectors, including dynamic and multi-angle light scattering for NP size and shape factor analysis, fluorescence for drug detection, and total organic carbon (TOC) to quantify the NPs and dissolved polymer in nanoformulations. The method was demonstrated on poly(lactic-co-glycolic acid) (PLGA) NPs loaded with coumarin 6 (C6) as a lipophilic drug surrogate.

Aggregation of varied organic coated magnetite nanoparticles: Adsorbed mass and thickness of coatings and interactions with natural organic matter.

Magnetite nanoparticles (MNPs) with varied organic coatings (OCs) which improved their stability have broad environmental applications. However, the adsorbed amounts and layer thickness of varied OCs onto MNPs during the synthesis were generally not or poorly characterized, and their interactions with natural organic matter (NOM) were still in progress. In this study, acetic (HAc), citric (CA), and polyacrylic acid (PAA) were selected as model OCs, the adsorption behaviors of OCs on MNPs were characterized under varied aqueous C/Fe ratios, and the aggregation behaviors of MNPs with varied OCs (OC-MNPs) at neutral pH (7.

Lead phosphate deposition in porous media and implications for lead remediation.

Phosphate addition is commonly applied as an effective method to remediate lead contaminated sites via formation of low solubility lead phosphate solids. However, subsequent transport of the lead phosphate particles may impact the effectiveness of this remediation strategy. Hence, this study investigates the mechanisms involved in the aggregation of lead phosphate particles and their deposition in sand columns as a function of typical water chemistry parameters.

Selective quantification of nanoplastics in environmental matrices by asymmetric flow field-flow fractionation with total organic carbon detection.

Nanoplastics are of rapidly emerging concern as ubiquitous environmental pollutants. However, fate and transport assessments are currently hindered by a need for new analytical methods that can selectively quantify nanoplastics in environmental matrices. This study presents the first proof of principle to hyphenate asymmetric flow field-flow fractionation (AF4) with total organic carbon (TOC) detection for nanoplastics analysis, as evaluated on mixtures of multimodal polystyrene nanoplastics in the presence of dissolved organic matter and clay colloids.

Asymmetric flow field-flow fractionation (AF4) with fluorescence and multi-detector analysis for direct, real-time, size-resolved measurements of drug release from polymeric nanoparticles.

Polymeric nanoparticles (NPs) are typically designed to enhance the efficiency of drug delivery by controlling the drug release rate. Hence, it is critical to obtain an accurate drug release profile. This study presents the first application of asymmetric flow field-flow fractionation (AF4) with fluorescence detection (FLD) to quantify release profiles of fluorescent drugs from polymeric NPs, specifically poly(lactic-co-glycolic acid) NPs loaded with enrofloxacin (PLGA-Enro NPs).

Coprecipitation of Fe/Cr Hydroxides with Organics: Roles of Organic Properties in Composition and Stability of the Coprecipitates.

Iron hydroxides are important scavengers for dissolved chromium (Cr) via coprecipitation processes; however, the influences of organic matter (OM) on Cr sequestration in Fe/Cr-OM ternary systems and the stability of the coprecipitates are not well understood. Here, Fe/Cr-OM coprecipitation was conducted at pH 3, and Cr hydroxide was undersaturated. Acetic acid (HAc), poly(acrylic acid) (PAA), and Suwannee River natural organic matter (SRNOM) were selected as model OMs, which showed different complexation capabilities with Fe/Cr ions and Fe/Cr hydroxide particles.

Prevention of infection caused by enteropathogenic E. coli O157:H7 in intestinal cells using enrofloxacin entrapped in polymer based nanocarriers.

Poor bioavailability of antibiotics, toxicity, and development of antibiotic-resistant bacteria jeopardize antibiotic treatments. To circumvent these issues, drug delivery using nanocarriers are highlighted to secure the future of antibiotic treatments. This work investigated application of nanocarriers, to prevent and treat bacterial infection, presenting minimal toxicity to the IPEC-J2 cell line.

Natural Organic Matter (NOM) Imparts Molecular-Weight-Dependent Steric Stabilization or Electrostatic Destabilization to Ferrihydrite Nanoparticles.

Ferrihydrite nanoparticles (Fh NPs) are ubiquitous in natural environments. However, their colloidal stability, and fate and transport behavior are difficult to predict in the presence of heterogeneous natural organic matter (NOM) mixtures. Here, we investigated the adsorption and aggregation behavior of Fh NPs exposed to NOM fractions with different molecular weights (MW).

Multiscale Evaluation of Moisture Susceptibility of Biomodified Bitumen.

This paper studies the selective adsorption and dewetting processes of various biomodifiers with respect to siliceous surfaces to determine dominant moisture damage mechanisms in bitumen doped with biomodifiers. Accordingly, it introduces four different biomodifiers made from various biomasses while explaining their differential effects on moisture susceptibility of bitumen when they are introduced to bitumen as a modifier to make commonly used biomodified binders. The biomodified binders studied here are made from extracts of biomass: wood pellets, miscanthus, corn stover, and animal waste.

Aggregation of ferrihydrite nanoparticles: Effects of pH, electrolytes,and organics.

To better understand the fate and transport of ferrihydrite nanoparticles (FNPs), which carry many contaminants in natural and engineered aquatic environments, the aggregation of FNPs was systematically investigated in this study. The pH isoelectric point (pH), surface zeta potential, and particle size evolutions of FNPs were measured under varied aqueous conditions using dynamic light scattering (DLS). The influence of pH (5.

Dynamic Intermolecular Interactions Control Adsorption from Mixtures of Natural Organic Matter and Protein onto Titanium Dioxide Nanoparticles.

Engineered nanoparticles (NPs) will obtain macromolecular coatings in environmental systems, changing their subsequent interactions. The matrix complexity inherent in natural waters and wastewaters greatly complicates prediction of the corona formation. Here, we investigate corona formation on titanium dioxide (TiO) NPs from mixtures of natural organic matter (NOM) and a protein, bovine serum albumin (BSA), to thoroughly probe the role of mixture interactions in the adsorption process.

Assessing the interactions of metal nanoparticles in soil and sediment matrices - A quantitative analytical multi-technique approach.

The impact and behavior of engineered nanomaterials (ENMs) entering the environment is an important issue due to their growing use in consumer and agricultural products. Their mobility and fate in the environment are heavily impacted by their interactions with natural particle components of saturated sediments and soils. In this study, functionalized gold nanoparticles (AuNPs - used as model ENMs) were spiked into complex solid-containing media (standard soils and estuarine sediment in moderately hard water).

Ultraviolet photo-oxidation of polyvinylpyrrolidone (PVP) coatings on gold nanoparticles.

Polymeric coatings are commonly applied to impart functionality and colloidal stability to engineered nanoparticles. In natural environments, transformations of the coating can modify the particle transport behavior, but the mechanisms and outcomes of these transformations have not yet been thoroughly evaluated. This study investigates the photo-transformations of polyvinylpyrrolidone (PVP) coatings on gold nanoparticles (AuNPs) under ultraviolet (UV) irradiation, representing light exposure in surface waters or other sunlit environments, and the impact on the AuNP colloidal stability.

Research highlights: improved understanding of ecological impacts resulting from nanomaterial-based remediation.

Nanomaterials are currently being used for remediation of soils and groundwater. However, the continued use of currently implemented nanomaterials and the systematic development of more effective and ecologically benign materials require a more complete understanding of their ecological impact, which should include the transport through the subsurface, acute, chronic and long term effects of exposure, and the role of nanomaterial characteristics (., composition, surface coating).

Research highlights: engineering nanomaterial-based technologies for environmental applications.

Nanomaterials are currently of interest for water treatment and remediation applications because they can exhibit high adsorption capacities and high reactivity to degrade or transform contaminants. Research is ongoing to further increase the adsorption capacity of the nanomaterials and to engineer nanomaterial-based treatment systems for contaminant removal. Here, we highlight three articles that advance this field by devising and testing approaches to improve the design of nanomaterials as well as their implementation in water treatment applications.

Photochemical transformations of thiolated polyethylene glycol coatings on gold nanoparticles.

Photochemical reactions can cause significant transformations of manufactured nanomaterials in sunlit environments. While transformations of inorganic nanoparticles (NPs) have been investigated extensively, less attention has been focused on the direct impact of aqueous photochemical reactions on adsorbed organic macromolecules that form the NP corona and strongly influence the surface interactions and reactivity that affect NP transport, fate, and toxicity. Here, we assess the transformations of methoxy polyethylene glycol thiol (mPEGSH) coatings on gold NPs (AuNPs) under controlled UV irradiation.

Correlation of the physicochemical properties of natural organic matter samples from different sources to their effects on gold nanoparticle aggregation in monovalent electrolyte.

Engineered nanoparticles (NPs) released into natural environments will interact with natural organic matter (NOM) or humic substances, which will change their fate and transport behavior. Quantitative predictions of the effects of NOM are difficult because of its heterogeneity and variability. Here, the effects of six types of NOM and molecular weight fractions of each on the aggregation of citrate-stabilized gold NPs are investigated.

Effects of molecular weight distribution and chemical properties of natural organic matter on gold nanoparticle aggregation.

The complexity of natural organic matter (NOM) motivates determination of how specific components in a NOM mixture interact with and affect nanoparticle (NP) behavior. The effects of two Suwannee River NOM fractions (separated by a 100,000 g/mol ultrafiltration membrane) on gold NP aggregation are compared. The weight-average molecular weight, Mw, for the unfractionated NOM was 23,300 g/mol, determined by size exclusion chromatography with multiangle light scattering.

Parameter identifiability in application of soft particle electrokinetic theory to determine polymer and polyelectrolyte coating thicknesses on colloids.

Soft particle electrokinetic models have been used to determine adsorbed nonionic polymer and polyelectrolyte layer properties on nanoparticles or colloids by fitting electrophoretic mobility data. Ohshima first established the formalism for these models and provided analytical approximations ( Ohshima, H. Adv.