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Rapid, inexpensive, and low-power/solar light-driven photocatalytic degradation of organic pollutants to deal with annually produced trillion tons of synthetic dye wastewater to prevent water scarcity issues, ecotoxicological risks, and human health has always been challenging. To overcome this limitation, the present study synthesized earth-abundant, inexpensive copper oxide nanosheets using a simple single-step hydrothermal route. The structural, physicochemical, and functional properties of the nanosheets have been characterized using several characterization techniques. The photocatalytic activity was studied for two commonly industrially used organic dyes, Methylene Blue (MB) and Rhodamine B (RhB). The importance of this work is the usage of a cheap commercially available Phillips UV light (11 W) as well as direct sunlight. With several optimized conditions, almost complete degradation of both dyes was achieved within 35 minutes under low-power UV light and within 70 minutes by the direct illumination of natural sunlight. The enhanced photocatalytic performance can be correlated to the synergetic effect of a higher charge transfer mechanism, good catalytic ‘active surface area’ availability (13.2 m²/g), and several optimized parameters that affect the reaction efficacy. Additionally, five repeated uses of nanosheets without sacrificing performance confirmed their stability and sustainability as a promising candidate for large-scale industrial textile wastewater remedies.

Evaporation can drive initially homogeneous multiphase liquid systems out of equilibrium to induce liquid-liquid phase separation (LLPS). Here, we demonstrate evaporative LLPS in microfluidic-generated emulsion microdroplets of polymer mixtures. The evaporation produces distinct polymer phases within the microdroplets. Phase separation occurs even with polymer combinations that do not form distinct phases in sessile droplet evaporation. We attribute this aspect to evaporation-driven solutal Marangoni flows and the interface capture accumulating the nuclei at the apex where the evaporation rate is the maximum. A fast coalescence and growth of the accumulated polymer nuclei occurs inside the droplets, unlike the capillary-flow-induced spread-out of the nuclei along the contact line in sessile drops. Our method of evaporation of the droplet cluster may facilitate studying LLPS in volume-limited environments and have implications for understanding LLPS in biological systems.

There are two commonly used drilling fluids, namely water-based muds (WBMs) and oil-based muds (OBMs); however, the latter type is more desirable for drilling unconventional oilfield reserves. To account for the potential encounter of hydrogen sulfide (H₂S) while drilling, the utilized OBMs should contain scavenger(s) with an effective H₂S mitigation capability in order to in-situ capture this very lethal and corrosive gas. To the best of our knowledge, studies on incorporating H₂S scavengers in OBMs and their testing are still greatly lacking in open literature. Thus, this study contributes into the filling of this gap by preparing a mineral oil-based drilling mud (MOBM) containing potassium permanganate as a promising, widely available, safe, and cheap H₂S scavenger. The MOBM also comprised other ingredients including rhamnolipid biosurfactant as an emulsifier and octadecanethiol-modified (i.e., hydrophobized) zinc nanoparticles (serving as weighting agent). These materials have not been widely utilized so far in open literature for the preparation of MOBM. The results obtained from this study demonstrated that this mud could fully scavenge H₂S for up to 22.7 h (i.e., breakthrough time), and it took about 63 h for the MOBM to become fully saturated with H₂S. The scavenged amounts of H₂S at these times reached 324.4 and 485.8 g/barrel MOBM, respectively. The formulated MOBM also displayed an appropriate non-Newtonian shear thinning behavior, where the apparent viscosity dropped sharply from about 1.96 to 0.71 Pa.s upon increasing the shear rate to from 1 to 10 s⁻¹, followed by a gradual decrease down to 0.31 Pa.s at a shear rate of 1000 s⁻¹. Additionally, the formulated mud is able to dissipate a significant amount of thermal energy as inferred from its estimated high activation energy of 34.93 kJ/mol, suggesting a good thermal stability of the MOBM. The present study reveals the possibility of formulating mineral OBMs with effective H₂S for safely drilling sour oil and gas reservoirs.

The large-scale culture of human induced pluripotent stem cells (hiPSCs) is essential for developing new pharmaceuticals and regenerative therapy methods. While for the development of cultured meat products, mass production of animal myoblasts is necessary. Both hiPSCs and animal myoblasts consume d-glucose as their energy source and produce l-lactate, which accumulates in cell culture media and inhibits cell proliferation. To make large-scale cell culture economically feasible, l-lactate removal and subsequent reuse of media are of high importance. The adsorption technique is attractive for l-lactate removal due to its low cost, ease of operation, and scalability. The current study is dedicated to 4-(2-hydroxyethyl)-1-piperazineethanesulfonate (HEPES) intercalated Mg–Al layered double hydroxide (LDH), which acts as a biocompatible anion-exchanger in media. HEPES‧Mg–Al LDH was able to remove l-lactate from hiPS cells and myoblast-relevant media selectively while mostly retaining d-glucose. Adsorbent exhibited dose-dependent cytotoxicity to hiPSCs and C2C12 cells, mainly related to elevated osmolarity, HEPES, and Mg levels and adsorption of media micro components. By employing alternatively prepared sol-gel derived HEPES‧Mg–Al LDH, the required adsorbent dose for efficient l-lactate removal was reduced to a safe level. The current study thoroughly evaluates Mg–Al layered double hydroxides as suitable adsorbents for cell culture media regeneration and discusses the limitations of Mg–Al LDHs in systems relevant to hiPS cells and C2C12 cells. This work promotes the cost-effective large-scale production of cells and gives insight into the limitations of Mg–Al LDHs applied to systems of biological origin.

The spread of bacterial infections aggravated by the development of microbial resistance to antibiotics requires the creation of protective antibacterial materials. Nanomaterials with biocides can provide antibacterial and antibiofilm properties against Gram-positive and Gram-negative bacteria. In this work, we synthesized nanocomposites with silver nanoparticles and different polyoxometalates of Keggin-structure (phosphomolybdic, phosphotungstic, and tungstosilicic acids) on eco-friendly nanoclay called halloysite. We found that the nanocomposite containing silver nanoparticles and phosphomolybdic acid deposited on the halloysite possesses the best antibacterial performance of all the obtained composites, having a minimal inhibitory concentration of 0.5 g/L against S. aureus, 0.25 g/L against P. aeruginosa and A. baumannii. This composite reduces the viability of formed biofilms at a concentration of 2.5 g/L.

A catalyst-free, green and efficient protocol for the one-pot, multi-component, synthesis of Methyleneisoxazole-5(4H)-ones (4a-l) from the reaction of Ethyl acetoacetate, aromatic aldehyde, and hydroxylamine hydrochloride in ethanol as green solvent under ultrasound irradiation at ambient temperature is described. This protocol offers several positive benefits, including simple handling, rapid reaction time period (≤10 mints), easy workup process, waste-free, gentler reaction conditions, ecologically friendly, cleaner reaction, absence of any a laborious purification and excellent yields.

The formation of an antibody (Ab) protein corona surrounding gold nanoparticles (AuNPs) is a crucial step in the design of immunological assays. The Ab corona stabilizes AuNPs, preventing their aggregation even at high ionic strength, and can be achieved by simply mixing Abs and AuNPs. In this paper, we report the unusual interactions between AuNPs and the antibody against L1 Cell Adhesion Molecule (L1CAM) purified from rabbits.

We have observed that at low ionic strength, the addition of a wide range of concentrations of rabbit monoclonal Abs against L1CAM protein immediately causes the coagulation of citrate-capped gold nanoparticles. This finding is surprising since the addition of proteins to colloidal gold usually forms a stable protein corona. The combination of extinction spectra, dynamic light scattering (DLS), and transmission electron microscopy (TEM) measurements reveals the presence of small clusters of AuNPs coated by the antibodies, as well as micron-sized antibody aggregates. Furthermore, static light scattering measurements demonstrate that Ab self-interactions are attractive (with a negative second virial coefficient, B2) and induce very slow Ab self-aggregation over several months. Overall, these results indicate that, at low ionic strength, the presence of AuNPs enhances Ab-Ab interactions, leading to their rapid aggregation. Simultaneously, the self-aggregation of the antibodies coating the AuNPs results in the formation of nanoparticle clusters.

The addition of NaCl to increase the ionic strength fully reverses the coagulation of AuNPs (the Ab-coated AuNPs repel each other) and dissolves the Ab aggregates (the Ab interactions become repulsive, with a positive B2). The AuNPs-induced enhancement of the aggregation process can be explained by considering that the highly favorable binding of Abs on the gold surface compensates for the entropic penalty associated with Ab-Ab aggregation.

The phenomenon we observed is specific to anti-L1CAM purified from rabbits and aligns with very old reports on AuNP coagulation induced specifically by the immunoglobulins present in the cerebrospinal fluid of patients suffering from neurosyphilis or multiple sclerosis (C. Lange Zeitschr. Chemotherap., 1912, 1, 44). It is reasonable to hypothesize that other antibodies exhibit this unusual behavior, so this work may aid in the interpretation of “anomalous” results that might otherwise be attributed to errors in fine-tuning AuNPs-Abs conjugation protocols.

Stability of dispersed materials remains an important question in a wide variety of fields such as cosmetics, catalysis, food or energy and the environment. As stability is directly linked to the size of the dispersed colloids it is essential to assess the size distribution of colloidal suspensions. Nowadays, microfluidic-based approaches generate increasing interest as they represent flexible and fast measurements allowing high throughput experimentations. However, characterization of colloidal dispersions is usually performed by dynamic light scattering (DLS), that requires static measurements as well as significant volumes, that are not compatible with on-line analysis and microfluidics. Moreover, due to flow-induced decorrelation terms, DLS measurements in microfluidic channels are only accurate at very low shear rates.

This work aimed at developing an on-line microfluidic device for dispersed materials characterization using DLS. The main challenges of this project were i) to adapt the microfabrication of the PDMS device in order to combine microchannels of hundreds of microns with a milli-fluidic cavity to perform the DLS measurements, and ii) to downsize the DLS set up. A PDMS microchip, consisting in a millimeter cavity for DLS measurements in parallel with a microchannel, was designed to perform the measurement on the sample without stopping the suspension flow during the microfluidic experiment. The cavity geometry was then optimized thanks to numerical simulation to ensure a good sweep efficiency and to downscale as much as possible without impairing the DLS signal.

By adapting the microfabrication process, a PDMS microfluidic chip was designed allowing the size measurements of successive suspensions containing 100 and 12 ​nm diameter particles. This work is a first step towards the implementation of a new technological building block for online microfluidic characterization.

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