Self-Promoted Hydroxyl Radical Releasing Magnetic Zn@Fe Particles.

Semiconductor photocatalysts, such as TiO2 and ZnO, have garnered significant attention for their ability to generate hydroxyl radicals, offering various practical applications. However, the reliance on UV light to facilitate electron-hole separation for hydroxyl radical production poses limitations. In this study, a novel approach is presented utilizing Zn@Fe core/shell particles capable of generating hydroxyl radicals without external energy input. The generation process involves electron donation from Zn to O2, resulting in the formation of radical species .O2 -/H2O2, followed by Fe-catalyzed conversion of H2O2 into hydroxyl radicals through the Fenton reaction. The release of .OH imparts good antimicrobial and antiviral properties to the Zn@Fe particles. Furthermore, the inclusion of Fe confers magnetic properties to the material. This dual functionality holds promise for diverse potential applications for the Zn@Fe particles.

Soft Surface Nanostructure with Semi-Free Polyionic Components for Sustainable Antimicrobial Plastic.

Surface antimicrobial materials are of interest as they can combat the critical threat of microbial contamination without contributing to issues of environmental contamination and the development drug resistance. Most nanostructured surfaces are prepared by post fabrication modifications and actively release antimicrobial agents. These properties limit the potential applications of nanostructured materials on flexible surfaces. Here, we report on an easily synthesized plastic material with inherent antimicrobial activity, demonstrating excellent microbicidal properties against common bacteria and fungus. The plastic material did not release antimicrobial components as they were anchored to the polymer chains via strong covalent bonds. Time-kill kinetics studies have shown that bactericidal effects take place when bacteria come into contact with a material for a prolonged period, resulting in the deformation and rupture of bacteria cells. A scanning probe microscopy analysis revealed soft nanostructures on the submicron scale, for which the formation is thought to occur via surface phase separation. These soft nanostructures allow for polyionic antimicrobial components to be present on the surface, where they freely interact with and kill microbes. Overall, the new green and sustainable plastic is easily synthesized and demonstrates inherent and long-lasting activity without toxic chemical leaching.

Microbicide surface nano-structures.

The prevention of infectious diseases is a global challenge where multidrug-resistant bacteria or "superbugs" pose a serious threat to worldwide public health. Microtopographic surfaces have attracted much attention as they represent a biomimetic and nontoxic surface antibacterial strategy to replace biocides. The antimicrobial effect of such natural and biomimetic surface nanostructures involves a physical approach which eradicates bacteria via the structural features of the surfaces without any release of biocides or chemicals. These recent developments present a significant proof-of-concept and a powerful tool in which cellular adhesion and death caused by a physical approach, can be controlled by the micro/nanotopology of such surfaces. This represents an innovative direction of development of clean, effective and nonresistant antimicrobial surfaces. The minireview will cover novel approaches for the construction of nanostructures on surfaces in order to create antimicrobial surface in an environmentally friendly, nontoxic manner.

ZnO Nanopillar Coated Surfaces with Substrate-Dependent Superbactericidal Property.

ZnO nanopillars coated on various surfaces are able to kill adhered bacteria and fungi due to their physical structure through a rupturing mechanism. Remarkably, zinc foil and galvanized steel surfaces with ZnO nanopillar coatings demonstrate an excellent remote bacteria-killing property. Their bacterial killing efficacy is several orders higher than ZnO nanopillars coated on other surfaces as well as ZnO nanoparticles themselves. Mechanistic study shows that the nanostructure surface kills adhered microbial cells by rupturing the cell wall, while superoxide (• O2- ) released from the ZnO coating with electrons donated from zinc via the Zn/ZnO interface rather than photoirritation is responsible for the superior remote killing. The results of this study represent a novel mechanism of surface disinfection and its application in water disinfection is also demonstrated.

Highly efficient chemical process to convert mucic acid into adipic acid and DFT studies of the mechanism of the rhenium-catalyzed deoxydehydration.

The production of bulk chemicals and fuels from renewable bio-based feedstocks is of significant importance for the sustainability of human society. Adipic acid, as one of the most-demanded drop-in chemicals from a bioresource, is used primarily for the large-volume production of nylon-6,6 polyamide. It is highly desirable to develop sustainable and environmentally friendly processes for the production of adipic acid from renewable feedstocks. However, currently there is no suitable bio-adipic acid synthesis process. Demonstrated herein is the highly efficient synthetic protocol for the conversion of mucic acid into adipic acid through the oxorhenium-complex-catalyzed deoxydehydration (DODH) reaction and subsequent Pt/C-catalyzed transfer hydrogenation. Quantitative yields (99 %) were achieved for the conversion of mucic acid into muconic acid and adipic acid either in separate sequences or in a one-step process.

Noncrystalline Zeolitic Imidazolate Frameworks Tethered with Ionic Liquids as Catalysts for CO2 Conversion into Cyclic Carbonates.

Noncrystalline zeolitic imidazolate frameworks (ZIFs) tethered with ionic liquids (ILs) were successfully employed as catalysts for mild CO2 conversion into cyclic carbonates for the first time. Notably, noncrystalline ZIFs exhibit outstanding catalytic performance in terms of activity, stability, and substrate suitability. Z3 was obtained through the simultaneous incorporation of a boronic acid group and ILs into its ZIF framework and exhibited a superior catalytic activity. A reaction mechanism for the propylene oxide-CO2 cycloaddition has been proposed, which integrates experimental findings with density functional theory calculations. The results indicate that zinc, ILs, and boronic acid play crucial roles in achieving high activity. Zinc and ILs are identified as key contributors to epoxide activation and ring opening, while boronic acid plays a crucial role in stabilizing the turnover frequency-determining transition states. The simplicity of this ZIF synthesis approach, combined with the high activity, stability, and versatility of the products, facilitates practical and efficient conversion of CO2 and epoxides into cyclic carbonates.

Nanoparticulate peroxidase/catalase mimetic and its application.

Ru sitting comfortably: Ruthenium oxide nanoparticles show bienzyme-like activities, and are capable of catalyzing H(2)O(2) disproportionation at pH 7.0 and peroxidation at pH 4.0 in aqueous solutions (see scheme). Their specific activities are better than many natural catalases and peroxidases and far better than bifunctional catalase/peroxidases.

Silane-functionalized polyionenes-coated cotton fabrics with potent antimicrobial and antiviral activities.

Bacterial and viral infections are posing a huge burden on healthcare industry. Existing antimicrobial textiles that are used to prevent infection transmission are lack of durability and antiviral activity. Here, we report on silane-functionalized polyionenes-coated cotton textiles with durable potent antimicrobial and antiviral activities. To obtain silane-functionalized polyionenes, silane group-containing monomers were synthesized and used to polymerize with co-monomers. These polyionenes were then conjugated onto the surface of cotton fabrics via covalent bonds. These polymers demonstrated broad-spectrum antimicrobial activity against various types of pathogenic microbes as evidenced by low effective concentration. The fabrics coated with these polymers exhibited potent bactericidal (>99.999%) and virucidal (7-log PFU reduction) activities. In addition, the antimicrobial efficacy was still more than 92% even after 50 times of washing. Evaluation of cytocompatibility and skin compatibility of the polymer-coated cotton fabrics in mice revealed that they were compatible with cells and mouse skin, and neither erythema nor edema was found in the area that was in contact with the polymer-coated fabrics. The silane-functionalized polyionenes are potentially promising antimicrobial and antiviral coating materials for textiles and other applications to prevent microbial and viral infections.

Sequence-selective recognition of nucleic acids under extremely low salt conditions using nanoparticle probes.

Extensive secondary structures in nucleic acid targets seriously impede the binding of complementary oligonucleotide probes. We report here a method to conduct the detection under extremely low salt conditions where the secondary structures are less stable and more accessible. A new type of nanoparticle probes prepared by functionalizing gold nanoparticles with nonionic morpholino oligos is employed. Because of the salt-independent hybridization of the probes with nucleic acid targets, nanoparticle assemblies can be formed in 2 mM Tris buffer solutions containing 0-5 mM NaCl, leading to the colorimetric target recognition. The sharp melting transitions of the target-probe hybrids allow discrimination of single-base imperfection, including substitution, deletion, and insertion. The method works effectively in detecting sequences that are likely to form secondary structure. In addition, the study provides direct evidence of the relationship between the aggregate structure and the melting behavior of the DNA-linked nanoparticles.

Broad spectrum antimicrobial PDMS-based biomaterial for catheter fabrication.

BACKGROUND: In addition to the widespread use of antibiotics in healthcare settings, the current COVID-19 pandemic has escalated the emergence of antibiotic resistance. Nosocomial infections among hospitalized patients is a leading site for such resistant microbial colonization due to prolonged use of invasive devices and antibiotics in therapies. Invasive medical devices, especially catheters, are prone to infections that could accelerate the development of resistant microbes. Often, catheters - particularly urinary catheters - are prone to high infection rates. Antibiotic-coated catheters can reduce infection rates and although commercially available, are limited in efficacy and choices. METHODS: Herein, a novel and facile method to fabricate PMDS-based biomaterial for the development of antimicrobial eluting catheters is presented. Silicone based organic polymer polydimethylsiloxane (PDMS) was used to prepare a biomaterial containing novel polymeric imidazolium antimicrobial compound. RESULTS: It was found that the PDMS-based biomaterials could eradicate microbial colonization even after 60 days in culture with continuous microbial challenge, be recycled over multiple uses, stored at room temperature for long-term usage and importantly is biocompatible. CONCLUSION: The PDMS-based biomaterial displayed biocidal functionality on microbes of clinical origin, which form major threats in hospital acquired infections.

Nanostructured Copper Surface Kills ESKAPE Pathogens and Viruses in Minutes.

In the search for a fast contact-killing antimicrobial surface to break the transmission pathway of lethal pathogens, nanostructured copper surfaces were found to exhibit the desired antimicrobial properties. Compared with plain copper, these nanostructured copper surfaces with Cu(OH)2 nano-sword or CuO nano-foam were found to completely eliminate pathogens at a fast rate, including clinically isolated drug resistant species. Additionally these nanostructured copper surfaces demonstrated potential antiviral properties when assessed against bacteriophages, as a viral surrogate, and murine hepatitis virus, a surrogate for SARS-CoV-2. The multiple modes of killing, physical killing and copper ion mediated killing contribute to the superior and fast kinetics of antimicrobial action against common microbes, and ESKAPE pathogens. Prototypes for air and water cleaning with current nanostructured copper surface have also been demonstrated.

Evaluation of the ZnO Nanopillar Surface for Disinfection Applications.

Much attention has been devoted to the synthesis and antimicrobial studies of nanopatterned surfaces. However, factors contributing to their potential and eventual application, such as large-scale synthesis, material durability, and biocompatibility, are often neglected in such studies. In this paper, the ZnO nanopillar surface is found to be amenable to synthesis in large forms and stable upon exposure to highly accelerated lifetime tests (HALT) without any detrimental effect on its antimicrobial activity. Additionally, the material is effective against clinically isolated pathogens and biocompatible in vivo. These findings illustrate the broad applicability of ZnO nanopillar surfaces in the common equipment used in health-care and consumer industries.

Exploring Reusability of Disposable Face Masks: Effects of Disinfection Methods on Filtration Efficiency, Breathability, and Fluid Resistance.

To curb the spread of the COVID-19 virus, the use of face masks such as disposable surgical masks and N95 respirators is being encouraged and even enforced in some countries. The widespread use of masks has resulted in global shortages and individuals are reusing them. This calls for proper disinfection of the masks while retaining their protective capability. In this study, the killing efficiency of ultraviolet-C (UV-C) irradiation, dry heat, and steam sterilization against bacteria (Staphylococcus aureus), fungi (Candida albicans), and nonpathogenic virus (Salmonella virus P22) is investigated. UV-C irradiation for 10 min in a commercial UV sterilizer effectively disinfects surgical masks. N95 respirators require dry heat at 100 °C for hours while steam treatment works within 5 min. To address the question on safe reuse of the disinfected masks, their bacteria filtration efficiency, particle filtration efficiency, breathability, and fluid resistance are assessed. These performance factors are unaffected after 5 cycles of steam (10 min per cycle) and 10 cycles of dry heat at 100 °C (40 min per cycle) for N95 respirators, and 10 cycles of UV-C irradiation for surgical masks (10 min per side per cycle). These findings provide insights into formulating the standard procedures for reusing masks without compromising their protective ability.

Iron-based nano-structured surfaces with antimicrobial properties.

Bactericidal nanopillar arrays on cicada wings represent a non-toxic antimicrobial technology as they work through physical cell rupture instead of a chemical mechanism. Here, we reported iron-based nanopillar arrays (FeOOH and Fe2O3) that can grow on various substrates by a simple solution method. These surfaces showed good structure-based antimicrobial activity. Even more simply, we have prepared urchin-type FeOOH and Fe2O3 particles, which can be easily coated onto various substrates to create structure-based disinfection surfaces. This work provides a simple and general methodology to apply this killed-by-structure technology for real world uses.

Monodisperse silica nanoparticles encapsulating upconversion fluorescent and superparamagnetic nanocrystals.

A new type of multifunctional silica-coated nanocomposites, detectable by their upconversion fluorescence and addressable by a magnetic field, was synthesized.

The direct conversion of sugars into 2,5-furandicarboxylic acid in a triphasic system.

A one-pot conversion of sugars into 2,5-furandicarboxylic acid (FDCA) is demonstrated in a triphasic system: tetraethylammonium bromide (TEAB) or water-methyl isobutyl ketone (MIBK)-water. In this reaction, sugars are first converted into 5-hydroxymethylfurfural (HMF) in TEAB or water (Phase I). The HMF in Phase I is then extracted to MIBK (Phase II) and transferred to water (Phase III), where HMF is converted into FDCA. Phase II plays multiple roles: as a bridge for HMF extraction, transportation and purification. Overall FDCA yields of 78 % and 50 % are achieved from fructose and glucose respectively.

Imidazolium salt-modified porous hypercrosslinked polymers for synergistic CO2 capture and conversion.

A new type of imidazolium salt-modified porous hypercrosslinked polymer (BET surface area up to 926 m(2) g(-1)) was reported. These porous materials exhibited good CO2 capture capacities (14.5 wt%) and catalytic activities for the conversion of CO2 into various cyclic carbonates under metal-free conditions. The synergistic effect of CO2 capture and conversion was observed.

Phosphonium salt incorporated hypercrosslinked porous polymers for CO2 capture and conversion.

Various novel hypercrosslinked porous polymers with phosphonium salt incorporated into their networks were developed. These porous materials have high BET surface areas (up to 1168 m(2) g(-1)) and can be used to selectively capture CO2 and efficiently convert CO2 into cyclic carbonates.

[Up-conversion luminescent properties of SrAl2O4: Eu2+, Dy3+ phosphors].

Strong green up-conversion emission was observed for the first time in europium and dysprosium co-doped strontium aluminate (SrAl2O4: Eu2+, Dy3+) phosphor under 980 nm infrared excitation at room temperature. The up-conversion emission spectrum of phosphors was quite different from that of down-conversion emission spectrum excited by ultraviolet or visible lights. The two kinds of emission spectra implied that there are different mechanisms of emission. The X-ray diffraction (XRD) results revealed that the prepared phosphor has the same crystal lattice and composition as that reported previously.

Purification of biomass-derived 5-hydroxymethylfurfural and its catalytic conversion to 2,5-furandicarboxylic Acid.

A simple and effective water extraction method is presented for the purification 5-hydroxylmethylfurfural (HMF) obtained from a biomass dehydration system. Up to 99% of the HMF can be recovered and the HMF in aqueous solution is directly converted to 2,5-furandicarboxylic acid (FDCA) as the sole product. This purification technique allows an integrated process to produce FDCA from fructose via HMF prepared in an isopropanol monophasic system, with an overall FDCA yield of 83% obtained. From Jerusalem raw artichoke biomass to FDCA via HMF prepared in a water/MIBK (methyl isobutyl ketone) biphasic system, an overall FDCA yield of 55% is obtained.