Predicting the fate of engineered nanoparticles (ENPs) once they are released in the environment is essential to evaluate their impacts to ecosystems. Microbial biofilms, as highly reactive compartments in soils and sediments, have the potential to impose strong controls on ENPs life cycle in natural settings. However, information regarding impacts of biofilms toward ENPs environmental fate are not easily accessible, and such evidences are collected and discussed in this review, in order to identify common trends and to better constrain the role played by these microbial structures. Biofilms are reported to exhibit important ENPs accumulation capacities, and short to long-term ENPs immobilization can thus be expected. Mechanisms that govern such accumulation and ENPs migration within biofilms depend strongly on electrostatic and hydrophobic interactions, as well as biofilm structural properties, such as density and permeability. They are a combination of key parameters that include ENPs size and surface properties, mineral substrate reactivity, ability to develop organic corona around ENPs, or formation of aggregates within the biofilm thickness. In addition, these microbial structures exhibit highly reactive microenvironments, and are consequently able to impose major ENPs transformations such as dissolution, through ligand- or redox-mediated pathways, as well as passivation or stabilization processes. Interestingly, exposure to toxic ENPs can even trigger a response from micro-organisms biofilms which has the potential to strongly modify ENPs speciation. Promising approaches to investigate the role of microbial biofilms for ENPs cycling in realistic systems are introduced through the use of mesocosms, medium-size replicated ecosystems that allow to integrate the complexity of natural settings. Finally, biofilm-mediated nanoparticles synthesis in man-impacted systems is presented. This raises important questions regarding biofilms role as secondary sources of nanoparticles.

Cr³⁺ doped nanoparticles (ZGO) with persistent luminescence properties have been dispersed in different media. We have observed that among them, Artificial Lysosomal Fluid (AFL) that mimics the intracellular environment can degrade ZGO.

The increase in fires at the wildland–urban interface has raised concerns about the potential environmental impact of ash remaining after burning. Here, we examined the concentrations and speciation of iron-bearing nanoparticles in wildland–urban interface ash. Total iron concentrations in ash varied between 4 and 66 mg g⁻¹. Synchrotron X-ray absorption near-edge structure (XANES) spectroscopy of bulk ash samples was used to quantify the relative abundance of major Fe phases, which were corroborated by transmission electron microscopy measurements. Maghemite (γ-(Fe³⁺)₂O₃) and magnetite (γ-Fe²⁺(Fe³⁺)₂O₄) were detected in most ashes and accounted for 0–90 and 0–81% of the spectral weight, respectively. Ferrihydrite (amorphous Fe(III)–hydroxide, (Fe³⁺)₅HO₈·4H₂O), goethite (α-Fe³⁺OOH), and hematite (α-Fe³⁺ ₂O₃) were identified less frequently in ashes than maghemite and magnetite and accounted for 0–65, 0–54, and 0–50% of spectral weight, respectively. Other iron phases identified in ashes include wüstite (Fe²⁺O), zerovalent iron, FeS, FeCl₂, FeCl₃, FeSO₄, Fe₂(SO₄)₃, and Fe(NO₃)₃. Our findings demonstrate the impact of fires at the wildland–urban interface on iron speciation; that is, fires can convert iron oxides (e.g., maghemite, hematite, and goethite) to reduced iron phases such as magnetite, wüstite, and zerovalent iron. Magnetite concentrations (e.g., up to 25 mg g⁻¹) decreased from black to gray to white ashes. Based on transmission electron microscopy (TEM) analyses, most of the magnetite nanoparticles were less than 500 nm in size, although larger particles were identified. Magnetite nanoparticles have been linked to neurodegenerative diseases as well as climate change. This study provides important information for understanding the potential environmental impacts of fires at the wildland–urban interface, which are currently poorly understood.

Stannous fluoride (SnF₂) is an effective antimicrobial agent and fluoride carrier to dental enamel. However, stannous complexes are known to readily oxidize in presence of O₂ and interact with a variety of ligands such as organic and inorganic compounds commonly present in toothpaste. Therefore, the stability of stannous species inside toothpaste remains an open question. Here we probe the speciation of Sn in solutions of known composition and in commercial toothpaste using Sn K-edge X-ray absorption spectroscopy. We show that the oxidation state of Sn and its chemical nature depends on both paste composition and time of opening, with Sn ultimately oxidizing into amorphous Sn(IV) hydroxide, Sn(OH)₄. These results highlight the effect of paste composition and utilization on the speciation of active ingredients such as SnF₂, and contribute to a rational design of toothpaste formulations that enhances the stability of stannous agents.

The past decade has seen a global transformation in how we communicate and connect with one another, making it easier to network and collaborate with colleagues worldwide. The COVID-19 pandemic led to a rapid and unplanned shift toward virtual platforms, resulting in several accessibility challenges that have excluded many people during virtual events. Virtual and hybrid conferences have the potential to present opportunities and collaborations to groups previously excluded from purely in-person conference formats. This can only be achieved through thoughtful and careful planning with inclusion and accessibility in mind, learning lessons from previous events' successes and failures. Without effective planning, virtual and hybrid events will replicate many biases and exclusions inherent to in-person events. This article provides guidance on best practices for making online/virtual and hybrid events more accessible based on the combined experiences of diverse groups and individuals who have planned and run such events. Our suggestions focus on the accessibility considerations of three event planning stages: (1) pre-event planning, (2) on the day/during the event, and (3) after the event. Ensuring accessibility and inclusivity in designing and running virtual events can help everyone engage more meaningfully, resulting in more impactful discussions that will more fully include contributions from the many groups with limited access to in-person events. However, while this article is intended to act as a starting place for inclusion and accessibility in online and hybrid event planning, it is not a fully comprehensive guide. As more events are run, it is expected that new insights and experiences will be gained, helping to continually update standards.