Prominent antibacterial effect of sub 5 nm Cu nanoparticles/MoS2composite under visible light.

Achieving an efficient and inexpensive bactericidal effect is a key point for the design of antibacterial agent. Recent advances have proved molybdenum disulfide (MoS2) as a promising platform for antimicrobial applications, while the combination of metal nanoparticle would promote the antibacterial efficiency. Nevertheless, the dispersivity, cheapness and safety of metal nanoparticle loaded on MoS2raised some concerns. In this paper, we successfully realized a uniform decoration of copper nanoparticles (CuNPs) on surface of MoS2nanosheets, and the size of CuNPs could be controlled below 5 nm. Under 5 min irradiation of 660 nm visible light, the synthesized CuNPs/MoS2composite demonstrated superior antibacterial performances (almost 100% bacterial killed) towards both Gram-negativeE. coliand Gram-positiveS. aureusover the single component (Cu or MoS2), while the bactericidal effect could last for at least 6 h. The synergism of photodynamic generated hydroxyl radical (·OH), oxidative stress without reactive oxygen species production and the release of Cu ions was considered as the mechanism for the antibacterial properties of CuNPs/MoS2. Our findings provided new insights into the development of two-dimensional antibacterial nanomaterials of high cost performance.

Point-of-care testing of butyrylcholinesterase activity through modulating the photothermal effect of cuprous oxide nanoparticles.

Butyrylcholinesterase (BChE) is an important indicator for clinical diagnosis of liver dysfunction, organophosphate toxicity, and poststroke dementia. Point-of-care testing (POCT) of BChE activity is still a challenge, which is a critical requirement for the modern clinical diagnose. A portable photothermal BChE assay is proposed through modulating the photothermal effects of Cu2O nanoparticles. BChE can catalyze the decomposition of butyrylcholine, producing thiocholine, which further reduce and coordinate with CuO on surface of Cu2O nanoparticle. This leads to higher efficiency of formation of Cu9S8 nanoparticles, through the reaction between Cu2O nanoparticle and NaHS, together with the promotion of photothermal conversion efficiency from 3.1 to 59.0%, under the excitation of 1064 nm laser radiation. An excellent linear relationship between the temperature change and the logarithm of BChE concentration is obtained in the range 1.0 to 7.5 U/mL, with a limit of detection of 0.076 U/mL. In addition, the portable photothermal assay shows strong detection robustness, which endows the accurate detection of BChE in human serum, together with the screening and quantification of organophosphorus pesticides. Such a simple, sensitive, and robust assay shows great potential for the applications to clinical BChE detection and brings a new horizon for the development of temperature based POCT.

Universal Antifouling and Photothermal Antibacterial Surfaces Based on Multifunctional Metal-Phenolic Networks for Prevention of Biofilm Formation.

Biofilms formed from the pathogenic bacteria that attach to the surfaces of biomedical devices and implantable materials result in various persistent and chronic bacterial infections, posing serious threats to human health. Compared to the elimination of matured biofilms, prevention of the formation of biofilms is expected to be a more effective way for the treatment of biofilm-associated infections. Herein, we develop a facile method for endowing diverse substrates with long-term antibiofilm property by deposition of a hybrid film composed of tannic acid/Cu ion (TA/Cu) complex and poly(ethylene glycol) (PEG). In this system, the TA/Cu complex acts as a multifunctional building block with three different roles: (i) as a versatile "glue" with universal adherent property for substrate modification, (ii) as a photothermal biocidal agent for bacterial elimination under irradiation of near-infrared (NIR) laser, and (iii) as a potent linker for immobilization of PEG with inherent antifouling property to inhibit adhesion and accumulation of bacteria. The resulted hybrid film shows negligible cytotoxicity and good histocompatibility and could prevent biofilm formation for at least 15 days in vitro and suppress bacterial infection in vivo, showing great potential for practical applications to solve the biofilm-associated problems of biomedical materials and devices.

An enhanced photoelectrochemical biosensor for colitoxin DNA based on HKUST-1/TiO2 and derived HKUST-CuO/TiO2 heterogeneous composites.

HKUST-1 MOFs and its derivative HKUST-CuO were coupled with TiO2 nanoparticles to form the heterogeneous composites of HKUST-1/TiO2 and HKUST-CuO/TiO2 based on their well-suitable bandgap energies (Eg). Compared with mono-component HKUST-1 or HKUST-CuO, the prepared composites displayed photoelectrochemical (PEC) response due to the synergistic effect from their heterogeneous structure. Higher photocurrent response was obtained on HKUST-CuO/TiO2-modified ITO electrode (HKUST-CuO/TiO2/ITO), which could be attributed to the hollow structure with a thin shell of HKUST-CuO greatly enhancing visible spectra harvesting. The CuO component in HKUST-CuO not only could accelerate electron transfer on the heterojunction interface but also effectively separate the photo-generated charge carriers (e-1/h+). Based on the excellent PEC performance of prepared photoactive composite material, under visible-light excitation (λ ≥ 420 nm) and with a working potential of 0 V (vs. Ag/AgCl), the S1 (probe DNA)/HKUST-CuO/TiO2/ITO PEC platform was successfully fabricated for colitoxin DNA detection without using ascorbic acid (AA) as an electron donor. Compared with the analysis results on S1/HKUST-1/TiO2/ITO electrode, S1/HKUST-CuO/TiO2/ITO displayed a wider linear response range from 1.0 × 10-6 to 4.0 × 10-1 nM with a lower detection limit of 3.73 × 10-7 nM (S/N = 3), the linear regression equation was ΔI (10-6 A) =0.5549-0.1858 log (CS2/M), which confirmed the HKUST-CuO could improve sensitivity because of its prominent PEC property. The relative standard deviation (RSD) of the PEC sensor for target DNA detection of 2.0 × 10-4 nM was 7.4%. The proposed DNA biosensor also possessed good specificity and stability. Hence, this reported work was a promising strategy for molecular diagnosis in the bio-analysis field. (A) Schematic illustration of the preparation process of the proposed PEC biosensors for colitoxin DNA detection. (B) The preparation process of HKUST-1 and HKUST-CuO.

Synergistic Multimodal Cancer Therapy Using Glucose Oxidase@CuS Nanocomposites.

Multimodal nanotherapeutic cancer treatments are widely studied but are often limited by their costly and complex syntheses that are not easily scaled up. Herein, a simple formulation of glucose-oxidase-coated CuS nanoparticles was demonstrated to be highly effective for melanoma treatment, acting through a synergistic combination of glucose starvation, photothermal therapy, and synergistic advanced chemodynamic therapy enabled by near-infrared irradiation coupled with Fenton-like reactions that were enhanced by endogenous chloride.

Two-Dimensional Metal-Organic Framework Film for Realizing Optoelectronic Synaptic Plasticity.

2D metal-organic framework (MOF) film as the active layer show promising application prospects in various fields including sensors, catalysis, and electronic devices. However, exploring the application of 2D MOF film in the field of artificial synapses has not been implemented yet. In this work, we fabricated a novel 2D MOF film (Cu-THPP, THPP=5,10,15,20-Tetrakis(4-hydroxyphenyl)-21H,23H-porphine), and further used it as an active layer to explore the application in the simulation of human brain synapses. It shows excellent light-stimulated synaptic plasticity properties, and exhibits the foundation function of synapses such as long-term plasticity (LTP), short-term plasticity (STP), and the conversion of STP to LTP. Most critically, the MOF based artificial synaptic device exhibits an excellent stability in atmosphere. This work opens the door for the application of 2D MOF film in the simulation of human brain synapses.

Exploring the potential of highly charged Ru(II)- and heteronuclear Ru(II)/Cu(II)-polypyridyl complexes as antimicrobial agents.

The antimicrobial potential of two ruthenium(II) polypyridyl complexes, [Ru(phen)2L1]2+ and [Ru(phen)2L2]2+ (phen = 1,10-phenanthroline) containing the 4,4'-(2,5,8,11,14-pentaaza[15])-2,2'-bipyridilophane (L1) and the 4,4'-bis-[methylen-(1,4,7,10-tetraazacyclododecane)]-2,2' bipyridine (L2) units, is herein investigated. These peculiar polyamine frameworks afford the formation of highly charged species in solution, influence the DNA-binding and cleavage properties of compounds, but they do not undermine their singlet oxygen sensitizing capacities, thus making these complexes attractive 1O2 generators in aqueous solution. L1 and L2 also permit to stably host Fenton -active Cu2+ ion/s, leading to the formation of mixed Ru2+/Cu2+ forms capable to further strengthen the oxidative damages to biological targets. Herein, following a characterization of the Cu2+ binding ability by [Ru(phen)2L2]2+, the water-octanol distribution coefficients, the DNA binding, cleavage and 1O2 sensitizing properties of [Ru(phen)2L2]2+ and [Cu2Ru(phen)2L2]6+ were analysed and compared with those of [Ru(phen)2L1]2+ and [CuRu(phen)2L1]4+. The antimicrobial activity of all compounds was evaluated against B. subtilis, chosen as a model for gram-positive bacteria, both under dark and upon light-activation. Our results unveil a notable phototoxicity of [Ru(phen)2L2]2+ and [Cu2Ru(phen)2L2]6+, with MIC (minimal inhibitory concentrations) values of 3.12 µM. This study highlights that the structural characteristics of polyamine ligands gathered on highly charged Ru(II)-polypyridyl complexes are versatile tools that can be exploited to achieve enhanced antibacterial strategies.

NIR-Driven Intracellular Photocatalytic O2 Evolution on Z-Scheme Ni3S2/Cu1.8S@HA for Hypoxic Tumor Therapy.

Hypoxia in a tumor microenvironment (TME) has inhibited the photodynamic therapy (PDT) efficacy. Here, Ni3S2/Cu1.8S nanoheterostructures were synthesized as a new photosensitizer, which also realizes the intracellular photocatalytic O2 evolution to relieve hypoxia in TME and enhance PDT as well. With the narrow band gap (below 1.5 eV), the near infrared (NIR) (808 nm) can stimulate their separation of the electron-hole. The novel Z-scheme nanoheterostructures, testified by experimental data and density functional theory (DFT) calculation, possess a higher redox ability, endowing the photoexited holes with sufficient potential to oxide H2O into O2, directly. Meanwhile, the photostimulated electrons can capture the dissolved O2 to form a toxic reactive oxygen species (ROS). Moreover, Ni3S2/Cu1.8S nanocomposites also possess the catalase-/peroxidase-like activity to convert the endogenous H2O2 into ·OH and O2, which not only cause chemodynamic therapy (CDT) but also alleviate hypoxia to assist the PDT as well. In addition, owing to the narrow band gap, they possess a high NIR harvest and great photothermal conversion efficiency (49.5%). It is noted that the nanocomposites also exhibit novel biodegradation and can be metabolized and eliminated via feces and urine within 2 weeks. The present single electrons in Ni/Cu ions induce the magnetic resonance imaging (MRI) ability for Ni3S2/Cu1.8S. To make sure that the cancer cells were specifically targeted, hyaluronic acid (HA) was grafted outside and Ni3S2/Cu1.8S@HA integrated photodynamic therapy (PDT), chemodynamic therapy (CDT), and photothermal therapy (PTT) to exhibit the great anticancer efficiency for hypoxic tumor elimination.

Novel Core-Sheath Cu/Cu2O-ZnO-Fe3O4 Nanocomposites with High-Efficiency Chlorine-Resistant Bacteria Sterilization and Trichloroacetic Acid Degradation Performance.

In order to solve two issues of chlorine-resistant bacteria (CRB) and disinfection byproducts (DBPs) in tap water after the chlorine-containing treatment process, an innovative core-sheath nanostructured Cu/Cu2O-ZnO-Fe3O4 was designed and synthesized. The fabrication mechanism of the materials was then systematically analyzed to determine the component and valence state. The properties of CRB inactivation together with trichloroacetic acid (TCAA) photodegradation by Cu/Cu2O-ZnO-Fe3O4 were investigated in detail. It was found that Cu/Cu2O-ZnO-Fe3O4 displayed excellent antibacterial activity with a relatively low cytotoxicity concentration due to its synergism of nanowire structure, ion release, and reactive oxygen species generation. Furthermore, the Cu/Cu2O-ZnO-Fe3O4 nanocomposite also exhibited outstanding photocatalytic degradation activity on TCAA under simulated sunlight irradiation, which was verified to be dominated by the surface reaction through kinetic analysis. More interestingly, the cell growth rate of Cu/Cu2O-ZnO-Fe3O4 was determined to be 50% and 10% higher than those of Cu/Cu2O and Cu/Cu2O-ZnO after 10 h incubation, respectively, manifesting a weaker cytotoxicity. Therefore, the designed Cu/Cu2O-ZnO-Fe3O4 could be a promising agent for tap water treatment.

Dual-Modal FexCuySe and Upconversion Nanoparticle Assemblies for Intracellular MicroRNA-21 Detection.

In situ quantification and imaging of low-level intracellular microRNAs (miRs) are important areas in biosensor research. Herein, DNA-driven FexCuySe@upconversion nanoparticle (UCNP) core@satellite nanostructures were developed to probe microRNA-21 (miR-21). FexCuySe@UCNP probes displayed dual signals: upconversion luminescence (UCL) and magnetic resonance imaging (MRI). In the presence of miR-21, the luminescence signal was restored and the T2 value was significantly increased because of dissociation of UCNPs from the assemblies. There was a good linear relationship between the dual signals and the expression levels of miR-21 in the range of 0.035-31.824 amol/ngRNA. The limit of detection (LOD) was 0.0058 amol/ngRNA for the luminescence intensity and 0.0182 amol/ngRNA for the MRI signal. This method opens a new avenue for intracellular miR-21 detection with high sensitivity and specificity.

Macrophage-Membrane-Camouflaged Disintegrable and Excretable Nanoconstruct for Deep Tumor Penetration.

The consolidation of nanovectors with biological membranes has recently been a subject of interest owing to the prolonged systemic circulation time and delayed clearance by the reticuloendothelial system of such systems. Among the different biomembranes, the macrophage membrane has a similar systemic circulation time, with an additional chemotactic aptitude, targeting integrin proteins. In this study, we aimed to establish a laser-activated, disintegrable, and deeply tumor-penetrative nanoplatform. We used a highly tumor-ablative and laser-responsive disintegrable copper sulfide nanoparticle, loaded it with paclitaxel, and camouflaged it with the macrophage membrane for the fabrication of PTX@CuS@MMNPs. The in vitro paclitaxel release profile was favorable for release in the tumor microenvironment, and the release was accelerated after laser exposure. Cellular internalization was improved by membrane encapsulation. Cellular uptake, cytotoxicity, reactive oxygen species generation, and apoptosis induction of PTX@CuS@MMNPs were further improved upon laser exposure, and boosted permeation was achieved by co-administration of the tumor-penetrating peptide iRGD. In vivo tumor accumulation, tumor inhibition rate, and apoptotic marker expression induced by PTX@CuS@MMNPs were significantly improved by laser irradiation and iRGD co-administration. PTX@CuS@MMNPs induced downregulation of cellular proliferation and angiogenic markers but no significant changes in body weight, survival, or significant toxicities in vital organs after laser exposure, suggesting their biocompatibility. The disintegrability of the nanosystem, accredited to biodegradability, favored efficient elimination from the body. In conclusion, PTX@CuS@MMNPs showed promising traits in combination therapies for excellent tumor eradication.

Biosynthetic new composite material containing CuO nanoparticles produced by Aspergillus terreus for 47Sc separation of cancer theranostics application from irradiated Ca target.

Copper oxide nanoparticles (CuO NPs) are needed in various fields, especially in the biomedical field. CuO NPs was obtained from Aspergillus terreus filtrate. CuO NPs structure was confirmed by UV-Vis spectrophotometry, as well as Fourier transform infrared (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). XRD offers the nanoparticles purity of CuO biosynthesis. CuO NPs are spherical when examined with TEM. The average size of CuO NPs from TEM was 15.75 ± 3.95 nm. New composite of P (AA-AN)-NPs CuO was synthesized by biotechnology and the induced γ-radiation. The distribution coefficient value (Kd) of 47Sc(III) as well as 47Ca(II) ions for the synthetic new composite was determined by batch technique. Radiochemical separation of 47Sc(III) from irradiated calcium target was studied using chromatographic column packed with the new composite material. The recovery yield of 78 ± 1.2% for 47Sc(III) was obtained using 1 M HCl. The quality control tests (chemical, radionuclide and radiochemical purities) of the eluted 47Sc confirmed that it's adequate for nuclear medicine applications.

Photoelectrochemical aptasensor for thrombin based on Au-rGO-CuS as signal amplification elements.

A photoelectrochemical platform for thrombin determination was developed based on Au-rGO-CuS as multiple signal amplification elements. CuInS2 QDs was used to sensitize burr-shape TiO2 (b-TiO2) to obtain a strong photocurrent. Under the specific recognition between aptamer and thrombin, a sandwichlike structure was formed and the Au-rGO-CuS-labeled aptamer (S2@Au-rGO-CuS) was immobilized on the electrode surface. This induced a sharp decrease in photocurrent. The phenomenon is mainly due to the fact that CuS NPs can competitively consume the light energy and electron donor with CuInS2/b-TiO2. The rGO can increase the amount of CuS NPs and the Au NPs can accelerate charge transferring which depress the recombination of photogenerated electrons and holes in CuS to further enhance the competitive capacity of CuS. The sandwichlike structure has a steric hindrance effect. Therefore, the S2@Au-rGO-CuS has a multiple signal amplification function for thrombin determination. Under optimal conditions, the PEC aptasensor exhibited a wide linear concentration range from 0.1 pM to 10 nM with a low detection limit of 30 fM (S/N = 3) for thrombin. Besides, the designed aptasensor performed well in the assay of human serum sample, indicating good potential for the determination of thrombin in real samples. Graphical abstract.

Eco-biocompatibility of chitosan coated biosynthesized copper oxide nanocomposite for enhanced industrial (Azo) dye removal from aqueous solution and antibacterial properties.

In the present study, the biogenic synthesis of an ecofriendly and non-toxic chitosan (CS) coated copper oxide NPs (CS-CuO nanocomposite) using Psidium guajava aqueous leaf extract. The biogenic synthesized CS-CuO nanocomposite was characterized by using UV-vis spectroscopy analysis (UV-Vis), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Field emission scanning electron microscopy with energy dispersive X-ray spectroscopy (FE-SEM-EDS), Dynamic light scattering (DLS), and Transmission electron microscopy (TEM). The prepared CS-CuO nanocomposite was evaluated for antibacterial activity by agar well diffusion method as well as minimum inhibitory concentrations (MIC) were assessed against both Gram-positive Streptococcus pneumoniae, Staphylococcus epidermidis and Gram-negative Escherichia coli, Proteus mirabilis with good inhibition effects on Gram-negative bacteria than the Gram-positive bacteria. The interaction of the CS-CuO nanocomposite with the bacterial membrane was visually observed by confocal laser scanning microscopy and the live/dead cells were differentiated by treatment with acridine orange and ethidium bromide dyes.

Catalytic and Photochemical Strategies to Stabilized Radicals Based on Anomeric Nucleophiles.

Carbohydrates, one of the three primary macromolecules of living organisms, play significant roles in various biological processes such as intercellular communication, cell recognition, and immune activity. While the majority of established methods for the installation of carbohydrates through the anomeric carbon rely on nucleophilic displacement, anomeric radicals represent an attractive alternative because of their functional group compatibility and high anomeric selectivities. Herein, we demonstrate that anomeric nucleophiles such as C1 stannanes can be converted into anomeric radicals by merging Cu(I) catalysis with blue light irradiation to achieve highly stereoselective C(sp3)-S cross-coupling reactions. Mechanistic studies and DFT calculations revealed that the C-S bond-forming step occurs via the transfer of the anomeric radical directly to a sulfur electrophile bound to Cu(II) species. This pathway complements a radical chain observed for photochemical metal-free conditions where a disulfide initiator can be activated by a Lewis base additive. Both strategies utilize anomeric nucleophiles as efficient radical donors and achieve a switch from an ionic to a radical pathway. Taken together, the stability of glycosyl nucleophiles, a broad substrate scope, and high anomeric selectivities observed for the thermal and photochemical protocols make this novel C-S cross coupling a practical tool for late-stage glycodiversification of bioactive natural products and drug candidates.

NIR-Driven Water Splitting H2 Production Nanoplatform for H2-Mediated Cascade-Amplifying Synergetic Cancer Therapy.

As a newly emerging treatment strategy for many diseases, hydrogen therapy has attracted a lot of attention because of its excellent biosafety. However, the high diffusivity and low solubility of hydrogen make it difficult to accumulate in local lesions. Herein, we develop a H2 self-generation nanoplatform by in situ water splitting driven by near-infrared (NIR) laser. In this work, core-shell nanoparticles (CSNPs) of NaGdF4:Yb,Tm/g-C3N4/Cu3P (UCC) nanocomposites as core encapsulated with zeolitic imidazolate framework-8 (ZIF-8) modified with folic acid as shell are designed and synthesized. Due to the acid-responsive ZIF-8 shell, enhanced permeability and retention (EPR) effect, and folate receptor-mediated endocytosis, CSNPs are selectively captured by tumor cells. Upon 980 nm laser irradiation, CSNPs exhibit a high production capacity of H2 and active oxygen species (ROS), as well as an appropriate photothermal conversion temperature. Furthermore, rising temperature increases the Fenton reaction rate of Cu(I) with H2O2 and strengthens the curative effect of chemodynamic therapy (CDT). The excess glutathione (GSH) in tumor microenvironment (TME) can deplete positive holes produced in the valence band of g-C3N4 in the g-C3N4/Cu3P Z-scheme heterojunction. GSH also can reduce Cu(II) to Cu(I), ensuring a continuous Fenton reaction. Thus, a NIR-driven H2 production nanoplatform is constructed for H2-mediated cascade-amplifying multimodal synergetic therapy.

Self-powered cathodic photoelectrochemical aptasensor based on in situ-synthesized CuO-Cu2O nanowire array for detecting prostate-specific antigen.

A facile and sensitive self-powered cathodic photoelectrochemical (PEC) aptasensor is reported for the detection of prostate-specific antigen (PSA) based on CuO-Cu2O nanowire array grown on Cu mesh (CuO-Cu2O NWA/CM) as electrode. The mixed narrow band gaps of the CuO-Cu2O heterostructure ensured its wide absorption band, effective electron/hole separation, and high photocatalytic activity in the visible region. In addition, nanowires directly grown on the substrate provided high specific surface area and exposed abundant active sites, thus guaranteeing its high photocatalytic efficiency. Therefore, the self-powered sensor exhibited favorable analytical performance with fast response, wide linear ranges of 0.01 to 5 ng/mL and 5 to 100 ng/mL, an acceptable detection limit of 3 pg/mL, and reasonable selectivity and stability. The proposed CuO-Cu2O NWA/CM can be considered a promising visible light-responsive photoactive material for fabrication of PEC aptasensor with high performance. Graphical abstract a Schematic illustration of construction process of PEC sensing platform based on the CuO-Cu2O composite for PSA detection. b Schematic mechanism of the operating PEC system.

Neuron-like cell differentiation of hADSCs promoted by a copper sulfide nanostructure mediated plasmonic effect driven by near-infrared light.

Nerve tissues are one of the most difficult tissues to repair due to the limited source of neural stem cells and the difficulty in promoting the neural differentiation of mesenchymal stem cells by growth factors. Electromagnetic field has been proved to have the ability to regulate stem cell differentiation. Although some research studies promoted the neural differentiation of stem cells using an external power source, it is still a big challenge to realize nerve repair in bodies because of the unwieldiness and complexity of the power supply equipment. Surface plasmons (SP) are electromagnetic oscillations caused by the interaction of free electrons and photons on a metal surface, and almost no one has used these localized electromagnetic oscillations to regulate stem cell differentiation. In this study, based on the concept proposed by our group that "the stem cell fate can be regulated by nanostructure mediated physical signals", the localized electromagnetic oscillation generated by the localized surface plasmon resonance (LSPR) of copper sulfide (CuS) nanostructures irradiated with near-infrared light has been proved to have positive regulation on stem cell maturation and neuron-like cell differentiation of human adipose-derived stem cells (hADSCs). This regulation method avoids the use of wire connection of an external power source, which realizes the stem cell fate regulation by an external field. In addition, this work demonstrated that it is promising to realize the light promoted nerve repair in bodies by using an implantable plasmonic nanomaterial with absorption in the near-infrared region within a human "optical window", which has important academic value and application prospect. As we know, this is the first time to use semiconductor nanostructures as a medium to regulate stem cell neuron-like cell differentiation by near-infrared light and the LSPR of a plasmonic nanomaterial, which will have great influence on biomedical engineering and attract broad attention from nanomaterials scientists, neurobiologists, and neurosurgeons.

Physical assessments of termites (Termitidae) under 2.45 GHz microwave irradiation.

Demands for chemical-free treatments for controlling insect pests are increasing worldwide. One such treatment is microwave heating; however, two critical issues arise when using microwaves as a heat source: intensive labor and excessive energy-consumption. Optimization is thus required to reduce energy consumption while effectively killing insects. Currently, the lethal effect of microwaves on insects is considered to be due to the temperature of the irradiated materials. This study examines how the conditions of irradiation, such as resonance or traveling mode, changed the conversion of electromagnetic energy into heat when 2.45 GHz microwaves penetrated the body of the termite, C. formosanus. Our results indicated that it is possible to heat and kill termites with microwaves under resonance condition. Termites were however found to be very tolerant to microwave irradiation as the permittivity of the insect was low compared with other reported insects and plants. Electron spin resonance revealed that termites contained several paramagnetic substances in their bodies, such as Fe3+, Cu2+, Mn2+, and organic radicals. Interestingly, irradiation with traveling microwaves hardly produced heat, but increased the organic radicals in termite bodies indicating non-thermal effects of microwaves.

Antibacterial Properties of Superhydrophilic Textured Copper in Contact with Bacterial Suspensions.

The method of pulsed laser processing with a nanosecond pulse duration was employed to obtain a nanotexture on the surface of copper alloys. The effect of the obtained micro- and nanotexture on the bactericidal properties of the surface upon its contact with suspensions containing of E. coli K12 C600 or K. pneumoniae 811 cells in a nutrient medium were studied. The evolution of cell morphology after on the nanotextured surface was analyzed using scanning electron microscopy, and changes in biological fluid during this contact were studied by mass spectrometry. It was shown that massive death of bacterial cells both in the suspension and on the nanotextured surface was determined by combined toxic effects of the hierarchically textured surface and high concentration of Cu2+ ions in the medium.