A new Pipistrelle bat from the oceanic Island of Príncipe (Western Central Africa).

We describe a population of pipistrelle-like bats from Príncipe Island (Gulf of Guinea, Western Central Africa) as a new species based on the molecular and morphological characteristics of six specimens collected more than 30 years ago. The description of this new species was not possible until the traditionally entangled systematics of the whole pipistrelle group was clarified in recent years with the inclusion of molecular techniques and adequate species sampling. In this new taxonomic framework, the new species was clearly included within the dark-winged group of the recently described genus Pseudoromicia. The pipistrelles from Príncipe Island present a moderately inflated skull in lateral view with inner upper incisors that are moderately bicuspids and a baculum distinctly long with expanded tips. Besides these morphological characters, the new bat species is distinguished by its dwarfism, being the smallest species recognized within the genus. The ecology and conservation status of this endemic island species are unknown and field studies are urgently needed to evaluate the situation and conservation threats to this new species in its natural habitat.

High-Throughput Sizing, Counting, and Elemental Analysis of Anisotropic Multimetallic Nanoparticles with Single-Particle Inductively Coupled Plasma Mass Spectrometry.

Nanoparticles (NPs) have wide applications in physical and chemical processes, and their individual properties (e.g., shape, size, and composition) and ensemble properties (e.g., distribution and homogeneity) can significantly affect the performance. However, the extrapolation of information from a single particle to the ensemble remains a challenge due to the lack of suitable techniques. Herein, we report a high-throughput single-particle inductively coupled plasma mass spectrometry (SP-ICP-MS)-based protocol to simultaneously determine the size, count, and elemental makeup of several thousands of (an)isotropic NPs independent of composition, size, shape, and dispersing medium with atomistic precision in a matter of minutes. By introducing highly diluted nebulized aqueous dispersions of NPs directly into the plasma torch of an ICP-MS instrument, individual NPs are atomized and ionized, resulting in ion plumes that can be registered by the mass analyzer. Our proposed protocol includes a phase transfer step for NPs synthesized in organic media, which are otherwise incompatible with ICP-MS instruments, and a modeling tool that extends the measurement of particle morphologies beyond spherical to include cubes, truncated octahedra, and tetrahedra, exemplified by anisotropic Cu NPs. Finally, we demonstrate the versatility of our method by studying the doping of bulk-dilute (<1 at. %) CuAg nanosurface alloys as well as the ease with which ensemble composition distributions of multimetallic NPs (i.e., CuPd and CuPdAg) can be obtained providing different insights in the chemistry of nanomaterials. We believe our combined protocol could deepen the understanding of macroscopic phenomena involving nanoscale structures by bringing about a statistics renaissance in research areas including, among others, materials science, materials chemistry, (nano)physics, (nano)photonics, catalysis, and electrochemistry.

Silver Nanoparticles and Ionic Silver Separation Using a Cation-Exchange Resin. Variables Affecting Their Separation and Improvements of AgNP Characterization by SP-ICPMS.

Silver nanoparticles (AgNPs) are frequently found in everyday products and, as a consequence, their release into the environment cannot be avoided. Once in aquatic systems, AgNPs interact with natural constituents and undergo different transformation processes. Therefore, it is important to characterize and quantify AgNPs in environmental waters in order to understand their behavior, their transformation, and their associated toxicological risks. However, the coexistence of ionic silver (Ag+) with AgNPs in aquatic systems is one of the greatest challenges for the determination of nanosilver. Ion-exchange resins can be used to separate Ag+ from AgNPs, taking advantage of the different charges of the species. In this work, Dowex 50W-X8 was used to separate Ag+ and AgNPs in order to easily determine AgNP concentrations using inductively coupled plasma optical emission spectroscopy. The separation methodology was successfully applied to river water samples with different ratios of Ag+ and AgNPs. However, the methodology is not useful for wastewater samples. The described methodology also demonstrated an improvement in the determination of the particle size of AgNPs present in river waters by single particle inductively coupled plasma mass spectrometry when a significant amount of Ag+ is also present.

Uptake, translocation and ligand of silver in Lactuca sativa exposed to silver nanoparticles of different size, coatings and concentration.

The broad use of silver nanoparticles (AgNPs) in daily life products enhances their possibilities to reach the environment. Therefore, it is important to understand the uptake, translocation and biotransformation in plants and the toxicological impacts derived from these biological processes. In this work, Lactuca sativa (lettuce) was exposed during 9 days to different coated (citrate, polyvinylpyrrolidone, polyethylene glycol) and sized (60, 75, 100 nm) AgNPs at different concentrations (1, 3, 5, 7, 10, 15 mg L-1). Total silver measurements in lettuce roots indicated that accumulation of AgNPs is influenced by size and concentration, but not by nanoparticle coating. On the other hand, nanosilver translocation to shoots was more pronounced for neutral charged and large sized NPs at higher NP concentrations. Single particle inductively coupled plasma mass spectrometry analysis, after an enzymatic digestion of lettuce tissues indicated the dissolution of some NPs. Ag K-edge X-ray absorption spectroscopy analysis corroborated the AgNPs dissolution due to the presence of less Ag-Ag bonds and appearance of Ag-O and/or Ag-S bonds in lettuce roots. Toxicological effects on lettuces were observed after exposure to nanosilver, especially for transpiration and stomatal conductance. These findings indicated that AgNPs can enter to edible plants, exerting toxicological effects on them.

Interaction of silver nanoparticles with mediterranean agricultural soils: Lab-controlled adsorption and desorption studies.

The production of silver nanoparticles (AgNPs) has increased tremendously during recent years due to their antibacterial and physicochemical properties. As a consequence, these particles are released inevitably into the environment, with soil being the main sink of disposal. Soil interactions have an effect on AgNP mobility, transport and bioavailability. To understand AgNP adsorption processes, lab-controlled kinetic studies were performed. Batch tests performed with five different Mediterranean agricultural soils showed that cation exchange capacity and electrical conductivity are the main parameters controlling the adsorption processes. The adsorption kinetics of different sized (40, 75, 100 and 200 nm) and coated (citrate, polyvinylpyrrolidone and polyethyleneglycol (PEG)) AgNPs indicated that these nanoparticle properties have also an effect on the adsorption processes. To assess the mobility and bioavailability of AgNPs and to determine if their form is maintained during adsorption/desorption processes, loaded soils were submitted to leaching tests three weeks after batch adsorption studies. The DIN 38414-S4 extraction method indicated that AgNPs were strongly retained on soils, and single-particle inductively coupled plasma mass spectrometry confirmed that silver particles maintained their nanoform, except for 100 nm PEG-AgNPs and 40 nm citrate-coated AgNPs. The DTPA (diethylenetriaminepentaacetic acid) leaching test was more effective in extracting silver, but there was no presence of AgNPs in almost all of these leachates.

Combination of cloud point extraction with single particle inductively coupled plasma mass spectrometry to characterize silver nanoparticles in soil leachates.

The expansion of silver nanoparticle (AgNP) applications in industry as antibacterial agents has generated an increment of their presence in the environment. Once there, their behavior is not clear because they can undergo different transformation processes that affect their transport, mobility, bioavailability, and toxicity. Therefore, the characterization and quantification of these emerging contaminants are important to understand their behavior and the toxicity effects that can be exerted on living beings. Single particle inductively coupled plasma mass spectrometry (SP-ICPMS) has demonstrated its ability to characterize and give quantitative information on AgNPs in aqueous samples. However, sometimes, the discrimination of the signal corresponding to AgNPs from the signal of dissolved species (Ag(I)) is a challenge. In the present contribution, it is shown that the presence of high amounts of Ag(I) hamper silver nanoparticle size and nanoparticle concentration determination in aqueous samples by SP-ICPMS. To facilitate signal discrimination of both chemical forms, the combination of cloud point extraction (CPE) with SP-ICPMS was studied. CPE experimental conditions to separate AgNPs from Ag(I) were assessed and adapted taking into account the characteristics of the SP-ICPMS technique. CPE and soil matrix effects on particle size were evaluated, showing that particle size was not modified after being in contact with soil matrix and after being separated by CPE. Additionally, frequently used calculation methods for SP-ICPMS data treatment were assessed. Finally, the potential of the developed methodology CPE-SP-ICPMS was evaluated in aqueous soil leachates contaminated with mixtures of AgNPs/Ag(I).