Advances in Amine-Surface Functionalization of Inorganic Adsorbents for Water Treatment and Antimicrobial Activities: A Review

Light-driven self-sterilizing cotton fabric and drug delivery: improvement of the antimicrobial activity of 4-sulfo-1,8-naphthalimide via its dendrimer and metallic dendrimer formation

The search for new bioactive substances with microbiological activity is dictated by the increasing resistance of the drugs used in clinical practice against various pathogenic microorganisms. In this respect, particular attention is paid to the modified dendrimers with biologically active substances and their metal complexes. This work describes synthesizing and characterizing a new copper complex of first-generation polypropylene imine (PPI) dendrimer, modified with 4-sulfo-1,8-naphthalimide. The new metallodendrimer [Cu2(E)(NO3)4] has been characterized by IR and electron paramagnetic resonance (EPR) spectroscopy. Two copper ions were found to form a complex with the dendrimer ligand. Cotton fabrics were treated with the dendrimer ligand (E), its monomer structural analog (M), and metallodendrimer. The microbiological activity of the three compounds and the treated cotton fabrics with them has been tested in the dark and after light irradiation against bacterial strains: Gram-positive B. cereus and Gram-negative P. aeruginosa. The results showed that the metallodendrimer was slightly more effective than the dendrimer ligand E and monomer M, and their activity was enhanced after light irradiation. The increase in antimicrobial activity after light irradiation was due to the generation of highly reactive singlet oxygen, which damages bacteria's cell membrane, leading to their inactivation. The similar activity against both types of bacteria indicates that all three compounds can be classified as broad-spectrum antimicrobial agents. The virucidal effects of the studied compounds were also tested against human adenovirus type 5 (HAdV5) and human respiratory syncytial virus (HRSV-S2) after 30 min/60 min. The newly synthesized compounds showed no activity against HAdV-5, but the activity against HSV-2 viruses increases with the prolongation of their interaction.

Surface Properties of Coatings Based on Iron Amino-Functionalized Oxides Deposited on DH 36 Steel Plates for Shipbuilding

The development of eco-friendly paint formulations is part of the transition process to more sustainable materials, which involves many industries such as offshore and shipbuilding, where the deterioration of steel in seawater is a key factor. This article aims to produce innovative coatings and test their protective action on DH 36 steel plates. SiO2 and TiO2 were modified with amino groups and iron sites to be used as filler for the design of ecological paint formulations The antimicrobial features of both NH2 groups and iron ionic species were combined with the chemical and mechanical stability of silica and titania, with silica-based powders showing increased efficacy. The surface properties of the resulting coatings were examined by determination of thickness, water wettability, roughness, and cross-cut adhesion tests (before and after a degradation test in seawater according to ASTM D870-97 standards). Preliminary tests of the microbiological activity of the iron amino functionalized materials were carried out to monitor, as proof of concept, the growth of some bacterial strains through measurements of optical density. The findings indicate that these coatings not only provide effective corrosion protection but are promising for enhancing the durability and environmental performance of steel surfaces exposed to marine environments.

Supported-amine-catalyzed cascade synthesis of spiro-thiazolone-tetrahydrothiophenes: assessing HSA binding activity

We have devised a supported-amine-catalyzed efficient synthesis of spiro-thiazolone-tetrahydrothiophenes via a sulfa-Michael/aldol cascade approach. The catalyst demonstrated sustained efficacy over 21 cycles. These derivatives were found to exhibit excellent binding abilities with purified human serum albumin as indicated by both in silico and in vitro-based experiments.

Taguchi optimisation of the synthesis of vine-pruning-waste hydrochar as potential adsorbent for pesticides in water

This research aimed to synthesise an effective hydrochar adsorbent from vineyard pruning wastes to remove emerging contaminants as a potential valorisation product. The adsorption capacity of the hydrochar was optimised using the Taguchi method. Four synthesis variables were evaluated: hydrothermal reaction temperature, use of H3PO4 as a catalyst, number of acetone washes, and type of chemical cold activation. The simultaneous adsorption of five model pesticides (clothianidin (CTD), acetamiprid (ACE), 2,4-D, metalaxyl (MET), and atrazine (ATZ)) at an initial pH of 7 was studied. At optimum conditions, the hydrochar presented a total adsorption capacity of 22.7 μmol/g, representing a 2.7-fold improvement with respect to pristine hydrochar performance. High percentage removals were achieved for all pollutants (85 % CTD, 94 % ACE, 86 % MET, and 95 % ATZ) except for 2,4-D (4 %). This research provides a valuable reference for developing hydrochar adsorbents for pollution control and the valorisation of biomass wastes.

Antibiofilm approaches as a new paradigm for treating infections

The lack of effective antibiotics for drug-resistant infections has led the World Health Organization to declare antibiotic resistance a global priority. Most bacterial infections are caused by microbes growing in structured communities called biofilms. Bacteria growing in biofilms are less susceptible to antibiotics than their planktonic counterparts. Despite their significant clinical implications, bacterial biofilms have not received the attention they warrant, with no approved antibiotics specifically designed for their eradication. In this paper, we aim to shed light on recent advancements in antibiofilm strategies that offer compelling alternatives to traditional antibiotics. Additionally, we will briefly explore the potential synergy between computational approaches, including the emerging field of artificial intelligence, and the accelerated design and discovery of novel antibiofilm molecules in the years ahead.

Zebrafish Insights into Nanomaterial Toxicity: A Focused Exploration on Metallic, Metal Oxide, Semiconductor, and Mixed-Metal Nanoparticles

Nanomaterials are widely used in various fields, and ongoing research is focused on developing safe and sustainable nanomaterials. Using zebrafish as a model organism for studying the potentially toxic effects of nanomaterials highlights the importance of developing safe and sustainable nanomaterials. Studies conducted on nanomaterials and their toxicity and potential risks to human and environmental health are vital in biomedical sciences. In the present review, we discuss the potential toxicity of nanomaterials (inorganic and organic) and exposure risks based on size, shape, and concentration. The review further explores various types of nanomaterials and their impacts on zebrafish at different levels, indicating that exposure to nanomaterials can lead to developmental defects, changes in gene expressions, and various toxicities. The review also covers the importance of considering natural organic matter and chorion membranes in standardized nanotoxicity testing. While some nanomaterials are biologically compatible, metal and semiconductor nanomaterials that enter the water environment can increase toxicity to aquatic creatures and can potentially accumulate in the human body. Further investigations are necessary to assess the safety of nanomaterials and their impacts on the environment and human health.

Electron-induced hydroamination of ethane as compared to ethene: implications for the reaction mechanism

The properties of carbonaceous materials with respect to various applications are enhanced by incorporation of nitrogen-containing moieties like, for instance, amino groups. Therefore, processes that allow the introduction of such functional groups into hydrocarbon compounds are of utmost interest. Previous studies have demonstrated that hydroamination reactions which couple amines to unsaturated sites within hydrocarbon molecules do not only proceed in the presence of suitably tailored catalysts but can also be induced and controlled by electron irradiation. However, studies on electron-induced hydroaminations so far were guided by the hypothesis that unsaturated hydrocarbons are required for the reaction while the reaction would be much less efficient in the case of saturated hydrocarbons. The present work evaluates the validity of this hypothesis by post-irradiation thermal desorption experiments that monitor the electron energy-dependent yield of ethylamine after electron irradiation of mixed C2H4:NH3 and C2H6:NH3 ices with the same composition and thickness. The results reveal that, in contrast to the initial assumption, ethylamine is formed with similar efficiency in both mixed ices. From the dependence of the product yields on the electron energy, we conclude that the reaction in both cases is predominantly driven by electron ionization of NH3. Ethylamine is formed via alternative reaction mechanisms by which the resulting NH2˙ radicals add to C2H4 and C2H6, respectively. The similar efficiency of amine formation in unsaturated and saturated hydrocarbons demonstrates that electron irradiation in the presence of NH3 is a more versatile tool for introducing nitrogen into carbonaceous materials than previously anticipated.

Recent Advances in Antibiofouling Materials for Seawater-Uranium Extraction: A Review

Nuclear power has experienced rapid development as a green energy source due to the increasing global demand for energy. Uranium, as the primary fuel for nuclear reactions, plays a crucial role in nuclear energy production, and seawater-uranium extraction has gained significant attention. However, the extraction of uranium is usually susceptible to contamination by microorganisms, such as bacteria, which can negatively affect the adsorption performance of uranium adsorption materials. Therefore, an important challenge lies in the development of new antibacterial and antiadhesion materials to inhibit the attachment of marine microorganisms. These advancements aim to reduce the impact on the adsorption capability of the adsorbent materials. This paper reviews the antibiofouling materials used for extracting seawater uranium, and corresponding mechanisms are discussed.

Hexamethylenetetramine functionalized graphene oxide-alginate beads nanocomposite as efficient sorbent for dye from aqueous solution

In this study, a novel eco-friendly sorbent, hexamethylenetetramine (HMTA) functionalized calcium alginate (AG) immobilized graphene oxide (GO) composite (AG-GO-HMTA) and hexamethylenetetramine functionalized calcium alginate composite (AG-HMTA) were prepared. Adsorption factors including pH impact, contact time, initial dye concentration, dosage, selectivity and reusability on methylene blue (MB) removal from water were investigated. The prepared sorbents were characterized using structural (e.g. XRD, FT-IR, EDAX), thermal (e.g. TGA, DTG), and morphological (e.g. SEM, BET) analysis techniques. The equilibrium adsorption data was described by the Langmuir and Freundlich isotherms, and the adsorption kinetic and thermodynamic parameters were investigated. The field studies and regeneration of the beads were investigated. AG-GO HMTA displays a well-defined porous structure and this desired morphology arising from high quality dispersion of HMTA within the AG-GO matrix. The highest adsorption capacities were observed at pH ∼ 5, meanwhile the adsorption of MB dye molecules, positively charged, onto the beads became faster due to strong electrostatic interactions. When the value of dosage is 0.01 g, the equilibrium concentration (mg/g) are maximum at 103, 110, 164, 168 mg/g for AG, AG-GO, AG-HMTA and AG-GO-HMTA, respectively. The present work shows that pseudo first order could describe the MB adsorption onto AG while it couldn't describe the MB adsorption onto the functionalized sorbents due to the hybrid materials complicity.

Comparing different surface modifications of zinc oxide nanoparticles in the developmental toxicity of zebrafish embryos and larvae

Nanotechnology allows for a greater quality of life, but may also cause environmental and organismic harm. Zinc oxide nanoparticles (ZnONPs) are one of the most commonly used metal oxide nanoparticles for commercial and industrial products. Due to its extensive use in various fields, there has already been much concern raised about the environmental health risks of ZnONPs. Many studies have investigated the toxicological profile of ZnONPs in zebrafish embryonic development; however, the specific characteristics of ZnONPs in zebrafish embryonic/larval developmental damage and their molecular toxic mechanisms of liver development are yet to be fully elucidated. This study aimed to reveal the hazard ranking of different surface modifications of ZnONPs on developing zebrafish and the toxicological mechanisms of these modified ZnONPs in liver tissue. The ~30 nm ZnONPs with amino- (NH₂- ZnONPs) or carboxyl- (COOH-ZnONPs) modification were incorporated during the embryonic/larval stage of zebrafish. Severe toxicity was observed in both ZnONP groups, especially NH₂-ZnONPs, which presented a higher toxicity in the low concentration groups. After prolonging the exposure time, the long-term toxicity assay showed a greater retardation in body length of zebrafish in the NH₂-ZnONP group. Response data from multiple toxicity studies was integrated for the calculation of the EC₅₀ values of bulk ZnO and ZnONPs, and the hazard levels were found to be decreasing in the order of NH₂-, COOH-ZnONPs and bulk ZnO. Notably, NH₂-ZnONPs induced ROS burden in the developing liver tissue, which activated autophagy-related gene and protein expression and finally induced liver cell apoptosis to reduce liver size. In conclusion, our findings are conducive to understanding the hazard risks of different surface modifications of ZnONPs in aquatic environments and will also be helpful for choosing the type of ZnONPs in future industrial applications.

Sceptrin-Au nano-aggregates (SANA) for overcoming drug-resistant Gram-negative bacteria

One of the recent advances in medical nanotechnology has been the development of nanoformulations to overcome drug-resistant bacterial infections. Herein, we disclose a new nano-antibiotic formulation based on sceptrin-Au nano-aggregates (SANA), which are drug-metal ion multiple complexes. Sceptrin is a natural compound from a marine organism (sponge) and was reported as a potential compound with drug activities. SANA consists of a sceptrin-Au ion and is a self-assembled nano-formation with electrostatic interaction. Interestingly, SANA showed superior antibiotic/antibiofilm activity toward carbapenem-resistant Gram-negative bacteria with low toxicity to red blood cells and endothelial cells. The working mechanism of SANA was identified with analysis of the extracellular reactive oxygen species level and membrane depolarization of bacteria. The feasibility of SANA as a new nano-antibiotic was demonstrated in CRPA-contaminated medical supplies where SANA inhibited the formation of biofilms as well as the growth of CRPA. This work presents a new concept for the development of next-generation nano-antibiotics and a more feasible clinical translational pathway.