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Metal-based compounds with excellent photo-physical properties show good photochemotherapeutic performance. But, low in-depth tissue penetration of light limits their effectivity for deeply buried tumors. Encouraged by the sonosensitizing ability of the traditional organic photosensitizers, here, we developed AuNPs@Ir1 as a sonosensitizer by hybridizing an organometallic Ir(III) complex (Ir1) with ultrasmall gold nanoparticles (AuNPs) for efficient tumor sonodynamic therapy (SDT) for the first time. AuNPs@Ir1 rapidly entered the cancer cells, produced 1O2, and catalytically oxidized NADH to NAD+ under ultrasound (US) irradiation, thus resulted in cancer cells oncosis. Because of efficient passive retention in tumors post intravenous injection, AuNPs@Ir1 further efficiently inhibited the growth of tumors in-vivo under US stimulation without long-term toxicity to other organs. Overall, this work presents the excellent US triggered in-vitro and in-vivo anticancer profile of the novel AuNPs@Ir1. It is expected to increase the scope of SDT for metal-based anticancer drugs.

The sulfur-coordinated organoiridium(III) complexes pbtIrSS and ppyIrSS, which contain C,N and S,S (dithione) chelating ligands, were found to inhibit breast cancer tumorigenesis and metastasis by targeting Wnt/β-catenin signaling for the first time. Treatment with pbtIrSS and ppyIrSS induces the degradation of LRP6, thereby decreasing the protein levels of DVL2, β-catenin and activated β-catenin, resulting in downregulation of Wnt target genes CD44 and survivin. Additionally, pbtIrSS and ppyIrSS can suppress cell migration and invasion of breast cancer cells. Furthermore, both complexes show the ability to inhibit sphere formation and mediate the stemness properties of breast cancer cells. Importantly, pbtIrSS exerts potent anti-tumor and anti-metastasis effects in mouse xenograft models through the blockage of Wnt/β-catenin signaling. Taken together, our results indicate that pbtIrSS has great potential to be developed as a breast cancer therapeutic agent with a novel mechanism.

The stability, dispersion, and rheological properties of clay suspensions are important in the process of drilling. Organic clays were obtained traditionally by cation exchange, which is thermally unstable due to weak electrostatic interaction between the cationic surfactant and clay minerals. The purpose of the present study was to yield a stable and well dispersed organic bentonite (OBent) as a rheological additive for oil-based drilling mud. The co-modified method was used to modify bentonite by a cationic surfactant (cetyltrimethoxyammonium bromide: CTAB) and a silane coupling agent (hexadecyltrimethoxysilane: HDTMS). Firstly, the basal spacing of bentonite was enlarged by intercalation of CTAB, and the thermal stability of bentonite was improved by covalent bonds of HDTMS onto the bentonite platelets. The as-prepared OBent was characterized by infrared analysis, X-ray diffraction analysis, thermogravimetric analysis, and scanning electron microscopy. The hydrophobicity, solubility, viscosity, and tribological performance of the OBent were also recorded. The test results showed that the hydrophobicity of the co-modified bentonite was improved significantly, and was greater than that of bentonite modified with single surfactant CTAB or HDTMS. The bentonite modified by the surfactant together with the silane coupling agent had stable rheology and a lower coefficient of friction than the single surfactant-modified bentonite because more HDTMS entered into the interlayer spaces and formed chemical bonds at the inner surface of platelets.

The incorporation of oxygen vacancy defects into the catalysts has been attracting significant interest for regulating the performance of photocatalysts. Single-atomic-site metal catalysts have als...

Microenvironmental parameters, including hypoxia, pH, polarity, viscosity and temperature, play pivotal roles in controlling the biological, physical or chemical behaviors of local molecules. Abnormal changes in these parameters would cause cellular malfunction or become a hallmark of the occurrence of severe diseases. Recently, a number of phosphorescent Ir(iii) complexes have been designed to respond to such parameters due to their attractive properties such as high photostability, long emission lifetimes, and environment-sensitive emission profiles. This review aims to provide a summary of the progress achieved in developing iridium-based probes responding to microenvironmental parameters in biological systems in recent years for diagnosis and treatment of diseases such as cancer and diabetes.

An HCBP1 peptide-ruthenium conjugate (Ru-β-Ala-FQHPSFI) as a potential candidate for targeted therapy of hepatoma was synthesized. Ru-β-Ala-FQHPSFI shows drastically enhanced cytotoxicity and high selectivity for hepatoma cells versus noncancer liver cells. Raman imaging shows that this peptide-based drug can be taken up well by the hepatoma cells compared with the bare ruthenium complex (Ru) and the opposite sequence peptide-ruthenium conjugate (Ru-β-Ala-IFSPHQF). This study presents a new strategy for the construction of tumor-targeting metal-based anticancer therapeutics.

Osmium(II) complexes usually exhibit an excellent NIR (near-infrared) emission, which conforms to the optical window in a biological system. Here we designed three mitochondria-targeted NIR terpyridine Os(II) complexes as photosensitizers, which demonstrated great NIR phosphorescence emission and long phosphorescence lifetime. The emission spectra of the osmium(II) complexes were red-shifted with increasing conjugated planes of their terpyridine ligand (Os3 > Os2 > Os1). Furthermore, the Os(II) complexes, especially Os3, could produce singlet oxygen and oxidize NADH under both 465 nm and 633 nm LED light irradiation. It was found that Os3 has certain phototoxicities upon red light irradiation, and have great potential for NIR photodynamic therapy.

Its limited therapeutic effect on hypoxic and refractory solid tumors has hindered the practical application of photodynamic therapy (PDT). Herein, we report our investigation of an osmium-peroxo complex (Os2), which is inactive in the dark, but upon light irradiation, can release a peroxo ligand O2•−, and is transformed into a cytotoxic osmium complex (Os1). The osmium-peroxo complex Os2 produces O2•− under light irradiation even in the absence of oxygen, and retains its phototoxicity in hypoxic tumors. Os1 is cytotoxic in the presence or absence of irradiation, behaves as a chemotherapeutic drug. The light-activated Os2 induces distinct ferroptosis, which is mediated by GSH degradation, lipid peroxide accumulation and down-regulation of glutathione peroxidase 4 (GPX4). In addition, Os2 causes photocatalytic oxidation of endogenous 1,4-dihydronicotinamide adenine dinucleotide (NADH) in living cancer cells, leading to ferroptosis. In vivo studies have confirmed that the Os2 can effectively inhibit the growth of solid hypoxic tumors in mice. A new strategy is proposed for the treatment of hypoxic tumors with metal-based drugs.

Four photo-catalysts of the general formula [Ir(CO6/ppy)2 (L)]Cl where CO6=coumarin 6 (Ir1-Ir3), ppy=2-phenylpyridine (Ir4), L=4'-(3,5-di-tert-butylphenyl)-2,2' : 6',2''-terpyridine (Ir1), 4'-(3,5-bis(trifluoromethyl)phenyl)-2,2' : 6',2''-terpyridine (Ir2 and Ir4), and 4-([2,2' : 6',2''-terpyridin]-4'-yl)-N,N-dimethylaniline (Ir3) were synthesized and characterized. These photostable photo-catalysts (Ir1-Ir3) showed strong visible light absorption between 400-550 nm. Upon light irradiation (465 and 525 nm), Ir1-Ir3 generated singlet oxygen and induced rapidly photo-catalytic oxidation of cellular coenzymes NAD(P)H. Ir1-Ir3 showed time-dependent cellular uptake with excellent intracellular retention efficiency. Upon green light irradiation (525 nm), Ir2 provided a much higher photo-index (PI=793) than the clinically used photosensitizer, 5-aminolevulinicacid (5-ALA, PI>30) against HeLa cancer cells. The observed necro-apoptotic anticancer activity of Ir2 was due to the Ir2 triggered photo-induced intracellular redox imbalance (by NAD(P)H oxidation and ROS generation) and change in the mitochondrial membrane potential. Remarkably, Ir2 showed in vivo photo-induced catalytic anticancer activity in mouse models.

As a basic structure of most polypyridinal metal complexes, [Ru(bpy)3]2+, has the advantages of simple structure, facile synthesis and high yield, which has great potential for scientific research and application. However, sonodynamic therapy (SDT) performance of [Ru(bpy)3]2+ has not been investigated so far. SDT can overcome the tissue-penetration and phototoxicity problems compared to photodynamic therapy. Here, we report that [Ru(bpy)3]2+ is a highly potent sonosensitizer and sonocatalyst for sonotherapy in vitro and in vivo. [Ru(bpy)3]2+ can produce singlet oxygen (1O2) and sono-oxidize endogenous 1,4-dihydronicotinamide adenine dinucleotide (NADH) under ultrasound (US) stimulation in cancer cells. Furthermore, [Ru(bpy)3]2+ enables effective destruction of mice tumors, and the therapeutic effect can reach deep tissues over 10 cm under US irradiation. This work paves a way for polypyridinal metal complexes to be applied to the noninvasive precise sonotherapy of cancer., Sonodynamic therapy has therapeutic promise due to its safety and good tissue penetration, but is currently bottlenecked due to a lack of efficient and safe sonosensitizers. Here the authors show that [Ru(bpy)3]2+ can produce singlet oxygen and sonooxidize NADH in deep tissue, and destroy mouse tumors effectively.

Due to conventional photodynamic therapy encountering serious problems of phototoxicity and low tissue-penetrating depth of light, other dynamic therapy-based therapeutic methods such as sonodynamic therapy (SDT) are expected to be developed. To improve the therapeutic response to SDT, more effective sonosensitizers are imperative. In this study, a novel water-soluble iridium(III)-porphyrin sonosensitizer (IrTMPPS) was synthesized and used for SDT. IrTMPPS generated ample singlet oxygen (1O2) under US irradiation and especially showed distinguished US-activatable abilities at more than 10 cm deep-tissue depths. Interestingly, under US irradiation, IrTMPPS sonocatalytically oxidized intracellular NADH, which would enhance SDT efficiency by breaking the redox balance in the tumor. Moreover, IrTMPPS displayed great sonocytotoxicity toward various cancer cells, and in vivo experiments demonstrated efficient tumor inhibition and anti-metastasis to the lungs in the presence of IrTMPPS and US irradiation. This report gives a novel idea of metal-based sonosensitizers for sonotherapy by fully taking advantage of non-invasiveness, water solubility, and deep tumor therapy.

A magnetic ionic liquid (abridged as MIL) [C6mim]5[Dy(SCN)8] was prepared and used as the magnetic lubricant of a steel-steel sliding pair. The tribological properties of the as-prepared MIL were evaluated with a commercially obtained magnetic fluid lubricant (abridged as MF; the mixture of dioctyl sebacate and Fe3O4, denoted as DIOS-Fe3O4) as a control. The lubrication mechanisms of the two types of magnetic lubricants were discussed in relation to worn surface analyses by SEM-EDS, XPS, and profilometry, as well as measurement of the electric contact resistance of the rubbed steel surfaces. The results revealed that the MIL exhibits better friction-reducing and antiwear performances than the as-received MF under varying test temperatures and loads. This is because the MIL participates in tribochemical reactions during the sliding process, and forms a boundary lubrication film composed of Dy2O3, FeS, FeSO4, nitrogen-containing organics, and thioether on the rubbed disk surface, thereby reducing the friction and wear of the frictional pair. However, the MF is unable to form a lubricating film on the surface of the rubbed steel at 25 °C, though it can form a boundary film consisting of Fe3O4 and a small amount of organics under high temperature. Furthermore, the excessive Fe3O4 particulates that accumulate in the sliding zone may lead to enhanced abrasive wear of the sliding pair.

In order to overcome the mismatching between traditional additives and DLC coatings in solid-liquid lubricating system. Cu nanoparticles modified with diisooctyl dithiophosphoric acid (NPCuDDP) were prepared and used as nano-additives in DLC/PAO solid-liquid lubricating systems. Four kinds of DLC coatings including amorphous carbon (a-C) and amorphous carbon doped with Si (a-C(Si)), Al (a-C(Al)) and H (a-C(H)) respectively, with a hardness range from 22 GPa to 7 GPa were used to study the tribological mechanism and adaptability of NPCuDDP to the hardness and composition of DLC coatings. It was found that NPCuDDP reduced the COF of DLC coatings/PAO systems by 19%–22% regardless of their hardness and composition and made the wear rate of all DLC coatings decrease by 2–3 orders of magnitude. While the composite of tribofilm was decided by the doped elements in DLC coatings. The doped element H inhibited the oxidation of copper in tribofilm, and led to the lowest wear rate of a-C(H) coating. The doped element Al in a-C(Al) facilitated the enrichment of phosphates on friction surface. The hardness rather than composition of DLC coatings determines whether traditional additive ZDDP can form tribofilm. ZDDP can only form Zinc polyphosphate tribofilm on the steel balls rubbed with a-C, a-C(Si) and a-C(Al) coatings whose hardness was over 12 GPa. The friction coefficient of the system increases greatly because of the high strength of ZDDP tribofilm. The high activity of soft metal nano-particle in NPCuDDP urged the formation of tribofilm on friction surface easily and produced a significant antifriction and antiwear effect, and is expected to replace traditional small molecule additives as the high-efficiency special lubricating oil additives for DLC coatings solid-liquid lubrication system.

A liquid phase method was adopted to encapsulate tungsten disulfide (WS2) nanosheets with oleylamine (OA) at a relatively lower temperature of 200 °C so as to acquire good solubility in organic lubricant base oil. The effect of OA-modified WS2 nanosheets on the tribological properties of poly-alpha olefin (PAO6) in a wide temperature range was examined with a four-ball machine and a UMT TriboLab test rig in a piston ring-cylinder liner contact mode. Results indicate that the OA-modified WS2 nanosheets added in PAO6 oil are able to improve the tribological properties of the lubricant base oil significantly at elevated temperatures; and they are advantageous over zinc dialkyldithiophosphates in improving the anti-wear ability of PAO6 from room temperature to 300 °C.

A novel hierarchical porous carbon-Fe3O4 composite are fabricated as an anode material for Li-ion batteries. In our design, hollow carbon spheres, HCSs for short, with elasticity are encapsulated in Fe3O4@C nanodisc. During the lithiation process, the out carbon shell confines particle-level outward expansion and ensure the structural integrity and stability. Meanwhile the embedded HCSs can provide void space to tolerate the volumetric expansion inwards. Subsequently, during the delithiation process, the HCSs could push the pulverized particles to contact together, ensuring good electrical contact between the pulverized particles and the outer carbon shell. The unique inward lithium-ion breathing design is helpful to maintain the structural integrity and ensure good inter- and intra-particle electrical contact. Therefore, the HCSs@Fe3O4@C nanodisc delivers an excellent high-rate cycling performance, giving a specific capacity of 595 mAh g−1 after 800 cycles at a current density of 1A g−1, and at a higher rate of 5 A g−1, having a specific capacity of 390 mAh g−1 after 1000 cycles. This work provides a new strategy for the design of high-volume expansion anodes in Li-ion batteries.

Ultrathin oil-soluble tungsten disulfide nanosheets surface-capped with oleylamine (OA-capped WS2) were prepared by liquid phase thermal decomposition method without any solid by-products, a facile method with potential for large-scale production. OA-capped WS2 nanosheets exhibit good dispersibility and long-term stability in poly alpha olefin oil and significantly enhance the lubricating properties of the base oil over a wide temperature range (from 25 °C to 200 °C). This is because the surface-capped WS2 nanosheets can be well adsorbed on friction surfaces forming a lubricating film (mainly WS2) and participate in tribological chemical reaction to generate a chemical reaction film consisting of WO3, FeS, FeSO4, iron oxides, and FeOOH on the worn steel surfaces during friction process.

Developing efficient and cost-effective electrocatalysts for hydrogen evolution reaction (HER) is highly desired for the hydrogen economy. In this study, we developed a facile microwave reduction method to synthesize single Pt atoms anchored on aniline-stacked graphene (Pt SASs/AG) with outstanding HER performance. Pt SASs/AG presents excellent HER activity with η = 12 mV at 10 mA cm−2 and a mass current density of 22 400 AgPt−1 at η = 50 mV, which is 46 times higher than that of commercial 20 wt% Pt/C. Moreover, the Pt SASs/AG catalyst is highly active and more stable than Pt/C. X-ray absorption fine spectroscopy and density functional theory calculations demonstrated that the coordination of atomically isolated Pt with the nitrogen of aniline optimized the electronic structure of Pt and the hydrogen adsorption energy, eventually promoting HER activity. This study provides a new avenue for the development of single-atom Pt electrocatalysts with high activity and stability.

Purple coneflower (Echinacea purpurea (L.) Moench) is a popular native North American herbal plant. Its major bioactive compound, chicoric acid, is reported to have various potential physiological functions, but little is known about its biosynthesis. Here, taking an activity-guided approach, we identify two cytosolic BAHD acyltransferases that form two intermediates, caftaric acid and chlorogenic acid. Surprisingly, a unique serine carboxypeptidase-like acyltransferase uses chlorogenic acid as its acyl donor and caftaric acid as its acyl acceptor to produce chicoric acid in vacuoles, which has evolved its acyl donor specificity from the better-known 1-O-β-D-glucose esters typical for this specific type of acyltransferase to chlorogenic acid. This unusual pathway seems unique to Echinacea species suggesting convergent evolution of chicoric acid biosynthesis. Using these identified acyltransferases, we have reconstituted chicoric acid biosynthesis in tobacco. Our results emphasize the flexibility of acyltransferases and their roles in the evolution of specialized metabolism in plants., Biosynthetic pathway of chicoric acid in purple coneflower has not been fully elucidated, though the compound has been shown to have potential health benefits. Here, the authors report the involvement of both BAHD and SCPL acyltransferases in its biosynthesis and show the pathway is unique to Echinacea species.

Photocatalytic anticancer profile of a IrIII photocatalyst (Ir3) with strong light absorption, high turnover frequency, and excellent biocompatibility is reported. Ir3 showed selective photo-cytotoxicity against cisplatin- and sorafenib-resistant cell lines while remaining dormant to normal cell lines in the dark. Ir3 exhibited excellent photo-catalytic oxidation of cellular co-enzyme, the reduced nicotinamide adenine dinucleotide phosphate (NADPH), and amino acids via a single electron transfer mechanism. The photo-induced intracellular redox imbalance and change in mitochondrial membrane potential resulted in necrosis and apoptosis of cancer cells. Importantly, Ir3 exhibited high biocompatibility and photo-catalytic anticancer efficiency as evident from in vivo zebrafish and mouse cancer models. To the best of our knowledge, Ir3 is the first IrIII based photocatalyst with such a high biocompatibility and photocatalytic anticancer therapeutic effect.

The sulfur-coordinated organoiridium(III) complexes pbtIrSS and ppyIrSS, which contain C,N and S,S (dithione) chelating ligands, were found to inhibit breast cancer tumorigenesis and metastasis by targeting Wnt/β-catenin signaling for the first time. Treatment with pbtIrSS and ppyIrSS induces the degradation of LRP6, thereby decreasing the protein levels of DVL2, β-catenin and activated β-catenin, resulting in downregulation of Wnt target genes CD44 and survivin. Additionally, pbtIrSS and ppyIrSS can suppress cell migration and invasion of breast cancer cells. Furthermore, both complexes show the ability to inhibit sphere formation and mediate the stemness properties of breast cancer cells. Importantly, pbtIrSS exerts potent anti-tumor and anti-metastasis effects in mouse xenograft models through the blockage of Wnt/β-catenin signaling. Taken together, our results indicate that pbtIrSS has great potential to be developed as a breast cancer therapeutic agent with a novel mechanism.

Oleylamine (hereinafter referred to as OM)-modified CeO2 nanoparticles were synthesized by a one-pot pyrolysis method. The tribological properties of the as-prepared CeO2 nanoparticles as the lubricant additive in poly-alpha olefin (PAO) were investigated with a four-ball machine, and their lubricating mechanism was discussed in relation to worn surface analyses by SEM, EDS, and XPS. Findings indicate that these nanoparticles exhibit good dispersibility as well as excellent anti-wear ability in PAO. This is because OM-modified CeO2 nanoparticles can catalyze the oxidation of metallic Fe to form ferrite oxide-containing tribo-film. Under the condition of ASTM D2266-2001, the same lowest WDS was obtained at the concentration of 0.2 wt% and 1.8 wt%. When the concentration of CeO2 is 0.2 wt%, a compact catalytic oxidation tribo-film is formed, which has more outstanding long-term anti-wear ability. When 1.8 wt% CeO2 is added, the tribo-film formed is the combination of catalytic oxidation film and ceria deposition film, which has more significant bearing capacity.

In this work, the large-scale produced copper nanowires (Cu NWs) were coated by nickel nanoparticles (Ni NPs) lay, i.e., Cu NWs@Ni. And under external magnetic field condition, Cu NWs@Ni as thermally conductive fillers were filled into epoxy (EP) resin to prepare the composites with high thermal conductivity (TC). The results showed that, when the magnetic field was 80 mT, Cu NWs@Ni (molar ratio of Cu:Ni = 10:5, and saturation magnetization (Ms) = 20.3 emu/g) can distribute in EP resin in an orderly manner along the direction of the magnetic field, endowing the composite with excellent TC at lower loading. Especially, when only 9 vol.% Cu NWs@Ni was filled, the TC along the direction of the magnetic field can reach 2.90 W/mK, which was 12.81 times than that of neat EP resin. Even so, the composite still maintained outstanding insulation properties, namely, the volume resistivity and the dielectric strength were 1.79 × 1015 Ω cm and 12.88 kV/mm, respectively. In addition, compared to that of neat EP resin, the composite still possessed splendid heat stability and mechanical properties. For the above positive improvement, the corresponding mechanisms were also discussed in detail.

Os(II) polypyridyl complexes usually display an excellent NIR (near-infrared) emission, which conforms to the optical window in a biological system. At the moment, there is only one commercial RNA dye, SYTO RNA-Select, which emits green fluorescence and only stains RNA in the fixed cells. Therefore, it is necessary to study NIR-emitting RNA probes in the live cells. Here, we study two novel osmium complexes with NIR luminescence for cell imaging and find the specific binding ability of these two osmium complexes with RNA. The osmium(II) complexes can selectively light up RNA and enable NIR luminescent imaging of RNA of the nucleus of the live cells. It is the first example of osmium complexes in application of RNA-specific luminescence imaging. This work suggests that RNA might be a novel target of osmium complexes.

Methyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propanoate (brand name T512) was loaded by mesoporous silica nanoparticles (MSNs) to afford the antioxidant for synthetic ester lubricant oil. Rotary oxygen bomb tests, pressure differential scanning calorimetry and oven oxidation tests were conducted to investigate the effect of the as-prepared antioxidant on the antioxidant stability of di-iso-octylsebacate (denoted as DIOS). When MSNs are combined with T512 at a properly selected mass ratio, the oxidation of the DIOS base oil is greatly slowed down while the oxidation induction time is significantly prolonged. This may be attributed to the gradual release of T512 from the MSNs and the adsorption of the oxidation products into the channels of MSNs.

Purpose The purpose of this paper is to study the tribological properties of Cu nanoparticles (NPs) as lubricant additives in three kinds of commercially available lubricants. Design/methodology/approach A four-ball machine is used to estimate the tribological properties of Cu NPs as lubricant additives in three kinds of commercially available lubricants. Three-dimensional optical profiler and electrical contact resistance are evaluated to investigate the morphology of the worn surfaces and the influence of Cu NPs on tribofilms. Findings Wear tests show that the addition of Cu NPs as lubricant additives could reduce wear and increase load-carrying capacity of commercially available lubricants remarkably, indicating that Cu NPs have a good compatibility with the existing lubricant additives in commercially available lubricants. Originality/value The tribological properties of Cu NPs as lubricant additives in three kinds of commercially available lubricants were investigated in this paper. These results are reliable and can be very helpful for application of Cu NPs as lubricant additives in industry.

Glutathione (GSH), cysteine (Cys), and homocysteine (Hcy) are three major biothiols, which play key roles in various biological systems. Accordingly, the development of phosphorescent probe of biothiols has attracted great attention in clinical applications. Here we report a ruthenium polypyridyl complex (1), which shows large phosphorescence quenching with 2.0 equivalents of Cu2+ ions. The non-phosphorescent 1−Cu ensemble sensor is formed and further applied to detect biothiols in living cancer cells. Among the various amino acids, GSH, Cys and Hcy induce distinct turn-on phosphorescence with high selectivity and insensitivity to biological relevant pH range and other proteins. As we know, this is the first report that Ru−Cu ensemble is used for probing endogenous thiols in the living cells.

Two isomeric ruthenium(II) complexes, [Ru-m-OH]2+ and [Ru-o-OH]2+ with two hydroxyl substituents at different positions of ligands, had been designed and synthesized. We found that the cellular uptake efficiency of Ru-o-OH]2+ was much better than Ru-m-OH]2+, and it exhibited higher toxicity toward cancer cell (BEL-7402) than its isomeric compound, [Ru-m-OH]2+. Importantly, [Ru-o-OH]2+ showed great selectivity between cancer cells and human normal cell (HBMEC). Confocal microscopy and inductively coupled plasma mass spectrometry (ICP-MS) indicated that [Ru-o-OH]2+ mainly accumulated in mitochondria. It could up-grade the expression of Bax and down-grade the level of Bcl-2, which trigger in mitochondrial apoptotic pathway. This study suggests that isomeric metal complexes might make differences in the field of medicine for anti-cancer.

Plants live in complex environments and need to cope with various biotic and abiotic stresses. Plant secondary metabolites are not only medicines/supplements for humans but are also important weapons used by plants for defense. Chicoric acid is the main active ingredient and is a major secondary metabolite of purple coneflower (Echinacea purpurea (L.) Moench). A special acyl donor changed serine carboxypeptidase-like acyltransferase catalyzes chicoric acid biosynthesis from caftaric acid and chlorogenic acid. The biological role of chicoric acid in purple coneflower and the significance of its biosynthesis being catalyzed by an acyl donor changed acyltransferase remain unclear. In the present study, correlation analysis and various in vitro experiments were investigated. Chicoric acid contents among different purple coneflower accessions were found to be negatively correlated with latitude, which indicated a possible role in ultraviolet protection. Ultraviolet light induced oxidative stress in purple coneflower leaves and upregulation of chicoric acid biosynthetic genes. However, chicoric acid was consumed by reactive oxygen species to alleviate oxidative stress. Chicoric acid provided ultraviolet protection by acting as a sunscreen and antioxidant agent. Notably, chicoric acid exhibited stronger ultraviolet absorption and antioxidant activity than the sum of its two substrates, which indicated the significance of its biosynthesis by an acyl donor changed acyltransferase. This study also implied that low doses of ultraviolet light might be good elicitors for simulating chicoric acid biosynthesis in purple coneflower.

Echinacea species are important medicinal plants with significant therapeutic potential and are widely used in the pharmaceutical industry. Different Echinacea species exhibit various chemical compositions and bioactivities. In the present study, the chemical differences, antioxidant ingredients, and diversity mechanisms of Echinacea species were studied. The aerial parts and roots of six different Echinacea species (E. purpurea (L.) Moench; E. pallida (Nutt.) Nutt.; E. angustifolia DC.; E. atrorubens (Nutt.) Nutt.; E. paradoxa (Norton) Britton var. paradoxa; E. sanguinea Nutt.) were collected for investigation. Through non-target metabolomics following targeted quantitative analysis, chicoric acid, caftaric acid, and echinacoside were found to be the main different components of Echinacea species. Coincidentally, these three chemicals were also the dominant antioxidant ingredients of Echinacea extracts, as determined by correlation analysis between chemical contents and in vitro antioxidant activities. Based on the cloning, sequencing, and measurement of the identified chicoric acid biosynthetic genes, the diversity of chicoric acid and caftaric acid among Echinacea species was determined by the precursor content, as well as by the expression levels of key biosynthetic genes. Overall, these results clarified the chemical differences and the possible mechanisms, as well as the bioactive ingredients, in Echinacea species and can guide the selection of Echinacea species for different industrial applications.

Inspired by the unique glass cell wall of diatom, we design a new nanostructure of human serum albumin nanoparticle (HSANP) coated with silica (HSA/SiO2), which consists of a core-satellite assembly of small silica nanoparticles on a single HSANP. The HSA/SiO2 nanoparticles are used for delivering ruthenium polypyridyl complexes into cells. The silica coating increases the Ru loading efficiency, and prevents the burst release of Ru from HSA/SiO2. The Ru release rate can be controlled by adjusting the amount of coated silica on HSANP, affording a drug delivery system with controlled drug release rate. The Ru-HSA/SiO2 nanoparticles show high stability in physiological condition, and significantly increase the Ru uptake into cells, which proceeds via clathrin-mediated endocytosis into the lysosomes. The silica coating takes no effect on the fluorescence intensity and ROS generation of loaded Ru in HSA/SiO2. Furthermore, Ru4-HSA/SiO2 exhibit weak cytotoxicity in dark, however, the nanodrug can be activated by light irradiation and generate ROS to damage cells, thus achieving an excellent photodynamic therapy efficiency. Therefore, the diatom-like nanostructure can function as sustained drug delivery nanocarrier of ruthenium polypyridyl complex and can be used for bioimaging and photodynamic therapy.

We have reported the formation of fluorescent CdSe/ZnS quantum dots (QDs) incorporated poly (styrene-co-maleic anhydride) spheres in nanoscale range with a simple emulsification solvent evaporation strategy. The influence parameters on the size and internal structure of the composite nanospheres, such as copolmer/QDs mass ratio and volume ratio of water/chloroform were systematically investigated. Our obtained QDs incorporated polymer nanospheres were suitable for some immunoassays which strongly required nano-sized fluorescent labels, such as lateral flow immunoassays (LFIAs), in which “easily flowing chromatographically along the strip” was needed. Finally, carboxyl-functionalized nanospheres were used as fluorescent tags and imported into LFIA system to on-site high-sensitively assess the level of C-reaction protein (CRP). Within the range of high-sensitive detection (from 0.04 to 10.0 mg/L), nanosphere-based LFIA sensor exhibited linear detection of CRP (R2 = 0.9995) and a detection limit of 0.04 mg/L, which may be useful to improve the risk assessment of cardiovascular disease.

Organometallic complexes containing ligands such as CO, carbenes, alkyls, phenyls, π-bound alkynes, alkenes, cyclopentadienyls and arenes possess properties which have often been exploited in areas such as catalysis and materials chemistry. They also offer opportunities for the design of new drugs with novel mechanisms of action. Here we focus on anticancer drugs which might complement successful platinum drugs in the clinic by widening the spectrum of activity, reducing side-effects and combatting resistance. The early clinical trials of titanocene dichloride highlighted the need to understand the aqueous solution chemistry of organometallic complexes and to identify their target sites in cancer cells. More recently organometallic Cp complexes of Fe(II), Rh(III) and Ir(III), and arene complexes of Ru(II) and Os(II), have been shown to target the redox balance in cancer cells, in contrast to DNA which is the target of cisplatin and related platinum drugs. The activity of both catalytic and photoactive organometallic compounds is being explored. Target recognition and activity are highly dependent not only on the metal and its oxidation state, but also the other coordinated ligands, the coordination number and geometry. In general, organometallic complexes are ‘pro-drugs’ which undergo activation in vivo (by ligand exchange or redox reactions), and the ligands themselves may be active components of the drug. A major challenge is to elucidate the chemistry of organometallic complexes directly in cells. The design of organometallic complexes for therapeutic and diagnostic applications in cancer and other areas of medicine present new and exciting research opportunities.

The redox properties of both metals and ligands in transition metal complexes offer unusual routes for new mechanisms of anticancer therapy. Metal complexes can introduce artificial reductive and oxidative stress into cancer cells, including behavior as photoactivatable agents and catalysts. Relatively inert metal complexes (“prodrugs”) can be activated by redox processes within cancer cells. Examples of pharmaceuticals activated by bioreduction include three PtIV and two RuIII compounds that have already entered clinical trials. More recently, novel CoIII, FeIII, PtIV, Ru(III/II), OsII, and IrIII complexes have been reported to exhibit redox-mediated anticancer activity. Redox activation strategies can introduce new methods to increase cancer cell selectivity and combat drug resistance. Using combination therapy together with redox modulators to increase potency is also possible. This essay focuses on metal complexes that are activated in the reducing environment of cancer cells.

Oleylamine (OM) and maleic anhydride dodecyl ester (MADE, synthesized at our laboratory) were adopted as the surface modifiers to prepare OM/MADE-capped tungsten disulfide (WS2) nanoparticles. An X-ray diffractometer and a transmission electron microscope were performed to analyze the microstructure and phase ingredients of the OM/MADE-capped WS2 nanoparticles. Moreover, a four-ball friction and wear tester and a reciprocating tribometer were employed to evaluate the tribological properties of the surface-capped WS2 nanoparticles as the lubricant additive in diisooctylsebacate (DIOS) from room temperature to 150 °C. The morphology of the worn steel surfaces and wear scars and their chemical states were investigated with a scanning electron microscope, three-dimensional profilometry, and an X-ray photoelectron spectroscope. Results show that OM-capped WS2 nanoparticles nearly have no effect on the tribological properties of the DIOS base oil. The OM/MADE-capped WS2 nanoparticles added in the same base stoc...

The synthesis, characterization and dynamic behavior of three complexes, cis-[Ru(bpy)2(NA)Cl][PF6] (1), cis-[Ru(bpy)2(NA)I][PF6] (2) and cis-[Ru(bpy)2(NA)2][PF6]2 (3), where bpy is 2,2′-bipyridine, NA is nicotinamide are reported. These were designed as potential photoactivated antibacterial agents. Their dynamic behavior in solution was explored using NMR to probe the presence of atropisomers. The data show that the NA ligand in the bis-NA complex 3 rotates freely at 298K on the NMR timescale; however, NA rotation in the mono-Cl and mono-I complexes 1 and 2 is hindered at the same temperature. DFT calculations suggested that this hindered rotation is due to hydrogen bonding between the NA protons closest to the nitrogen of the pyridine ring and the halide ligand. Interestingly Cl hinders rotation more than I, which corresponds to hydrogen bonding ability. Such dynamic behavior may influence the recognition of polypyridyl ruthenium drugs by biological targets.

A kind of N-containing borate ester (DEBE) with a double five-member-ring structure as a lubricant additive was synthesized by using boric acid, diethanolamine and alkylphenol polyoxyethylene ether as the starting materials. The tribological performance of the as-prepared DEBE was evaluated using a four-ball friction and wear tester in different base oils, such as liquid paraffin (LP), poly-alpha-olefin (PAO) and dioctyl sebacate (DIOS), while the morphologies of the worn scars of the steel balls were observed using a scanning electron microscope. The chemical components on the worn surfaces of the steel balls were analyzed using X-ray photoelectron spectroscopy. The tribological mechanisms in base oils of LP, PAO and DIOS were also explored. The results show that as-prepared borate ester DEBE possessed good antiwear properties in LP and PAO and can be used as a promising S- and P-free environmentally acceptable lubricating oil additive. However, the antiwear ability decreased when the additive DEBE was added to DIOS base oil. The antiwear ability of the DEBE borate esters used as an additive in DIOS might be closely related to competitive adsorption between DEBE borate ester and DIOS ester oil. Namely, compared with the DEBE additive, the DIOS base oil is first to adsorb to the metal surface because of the higher polarity. Moreover, a small amount of the additive absorbed on the metal surface may influence the continuity and compactness of the oil film formed by DIOS alone, resulting in destruction of the tribological properties of DIOS.

Poly(p-methoxyphenol-phenylamine), denoted as P(MOP-PA), was synthesized via the enzymatic oligomerization of p-methoxyphenol and phenylamine monomers in the presence of horseradish. The structure of the as-synthesized product was confirmed by Fourier transform infrared spectrometry, time-of-flight mass spectrometry, and elemental analysis, and the oligomerization process was studied by high-performance liquid chromatography. Moreover, the antioxidation behavior of P(MOP-PA) as an antioxidant in several ester oils was evaluated by rotary oxygen bomb test and pressurized differential scanning calorimetry, and its antioxidant mechanism was discussed. It was found that, as the antioxidant in various base oils, P(MOP-PA) exhibits excellent antioxidation ability at elevated temperatures of 150 and 210 °C. In addition, P(MOP-PA) has an antioxidant ability that is better than that of poly(p-methoxyphenol), and it exhibits an antioxidation ability in synthetic ester oil, such as di-iso-octyl sebacate, that is muc...

Mitochondrial pH is known to be alkaline (near 8.0) and has emerged as a potential factor for mitochondrial function and disorder. Here we investigate two pairs of isomeric phosphorescent Ir(iii) complexes (1-4) that show mitochondrial pH-responsive properties and induce mitochondrial dysfunction during photodynamic therapy. These complexes are designed to function by controlling the protonation of the benzimidazole and carboxyl groups. 1 and 2 exhibit enhanced emission intensity and a blue-shift emission change in response to pH alterations from 6.0 to 8.0. They have ideal pKa values (7.49 for 1 and 7.41 for 2) and show mitochondria-specific phosphorescence staining in situ, thereby allowing the monitoring of mitochondrial pH in live cells. 3 and 4 produce abundant intracellular ROS and exhibit high phototoxicities against cancer cells. Interestingly, these pH-responsive probes can be utilized to monitor the change in mitochondrial pH and mitochondrial damage during photodynamic therapy (PDT), which provides a convenient method for the in situ monitoring of therapeutic effects and the assessment of treatment outcomes.

Hypoxic tumours are a major problem for cancer photodynamic therapy. Here, we show that photoredox catalysis can provide an oxygen-independent mechanism of action to combat this problem. We have designed a highly oxidative Ir(III) photocatalyst, [Ir(ttpy)(pq)Cl]PF6 ([1]PF6, where 'ttpy' represents 4'-(p-tolyl)-2,2':6',2''-terpyridine and 'pq' represents 3-phenylisoquinoline), which is phototoxic towards both normoxic and hypoxic cancer cells. Complex 1 photocatalytically oxidizes 1,4-dihydronicotinamide adenine dinucleotide (NADH)-an important coenzyme in living cells-generating NAD• radicals with a high turnover frequency in biological media. Moreover, complex 1 and NADH synergistically photoreduce cytochrome c under hypoxia. Density functional theory calculations reveal π stacking in adducts of complex 1 and NADH, facilitating photoinduced single-electron transfer. In cancer cells, complex 1 localizes in mitochondria and disrupts electron transport via NADH photocatalysis. On light irradiation, complex 1 induces NADH depletion, intracellular redox imbalance and immunogenic apoptotic cancer cell death. This photocatalytic redox imbalance strategy offers a new approach for efficient cancer phototherapy.

The polarity of a cell is the feedback of a series of complex mechanisms that establish and maintain functionality of particular domains. Many cellular processes involved in the spatial arrangement and protein composition such as differentiation, localized membrane growth, activation of the immune response, directional cell migration, and vectorial transport of molecules across cell layers may lead to changes and development of polarity. In this work, a phosphorescent iridium complex was reported for sensitively probing environmental and cellular polarity. This probe exclusively targeted the endoplasmic reticulum (ER) and successfully in situ tracked polarity variations during ER stress in living cells. Importantly, the blood of diabetic mice in the presence of this probe appears to have distinguished phosphorescence compared with the blood of normal mice, indicating that the probe probably monitors blood polarity in diabetes.

Abnormal levels of biological viscosity are closely associated with some diseases and malfunction (e.g. cancer, diabetes). Sensitive viscosity probes are of significant importance in disease diagnosis and remain an unmet need. In this research, we present a novel viscosity-sensitive dinuclear Ir(III) complex (1), which freely rotates and shows weak phosphorescence in a low-viscosity environment, while in viscous media, both the phosphorescence intensity and lifetime are enhanced significantly. 1 can further be applied for phosphorescence lifetime imaging (PLIM) and measure lysosomal microviscosity with high accuracy and reliability. Interestingly, this PLIM property can distinguish between tumorous and nontumorous cells. Importantly, the probe shows much stronger phosphorescence in the fresh blood of diabetic mice than that of normal mice. This work offers a potential efficient probe for diagnosing viscosity related diseases.

Superhydrophobic materials exhibit diverse application potential in various fields due to their excellent self-cleaning properties. However, it is still challenging to prepare bionic superhydrophobic materials employing the green methods. In this study, the “condenser” (simulated by a red copper spiral tube) with excellent self-cleaning properties and antibacterial activity has been prepared by a simple one-step “soapy water” immersion process without introducing any other reagents. The results demonstrate that the Cu[CH3(CH2)10COO]2 lamellar nanostructures are formed on the surface of “condenser” owing to the oxidation of copper upon immersion in the sodium laurate aqueous solution. The as-formed nanostructures exhibit excellent self-cleaning performance and can significantly inhibit the growth and proliferation of Escherichia coli and Staphylococcus aureus, which is significant for the upgradation of the safety and comfort features of the new generation air-conditioners. Moreover, the ruptured superhydrophobic coating on the copper tube can be effectively restored by a facile re-soaking process. Therefore, the present approach, with simple one-step solution-immersion process, low cost, short immersion period, environmental friendliness and optimal applicability to a variety of metal structures of different shapes, represents a promising strategy for fabricating the low-cost superhydrophobic surfaces applicable to the condenser and heat transfer systems, thereby, promoting the development of the self-cleaning and antibacterial smart devices.

Forming carbon based tribo-film in situ is an environmentally friendly and efficient way to solve the boundary lubrication problem. In this paper, the cubic nickel nanoparticles (average particle size 21.3 nm) modified by oleylamine were used as additives of poly-alpha-olefin (PAO6) for extreme pressure (EP) lubrication between bearing steel and stainless steel. It was found that in the range of 1.4–2.2 GPa contact pressure, nickel nanoparticles can catalyze the carbonization of PAO6 on the friction surface, which reduced the wear rate by 94%, the friction coefficient (COF) by 79%, and can withstand the extreme pressure friction of 4.2 GPa. XPS, EDS, TEM and FIB were used to analyze the microstructure, composition and chemical state of tribo-film. The tribo-film is composed of oxide layer, concrete structure layer and amorphous carbon layer. The oxide layer formed by oxidation of steel surface produced better binding force with the steel substrate. Nickel nanoparticles catalyze the carbonization of PAO6 to form a concrete structure with nickel nanocrystals embedded in the amorphous carbon phase, which provides high bearing capacity. The carbon layer graphitizes under the friction induction to form a lubricating layer with low friction characteristics. Oleylamine modified nickel nanoparticles is expected to be widely used as an environmentally friendly EP additive.

N-containing borate ester (MEBE) with five-member ring structure as a lubricant additive was synthesised. The tribological properties in liquid paraffin (LP), poly-alpha-olefin (PAO) and dioctyl sebacate (DOS) were evaluated, and the action mechanisms in different base oils were also explored. It was found that as-synthesised borate ester possesses excellent antiwear performance in LP and PAO. XPS analysis suggests that the additive forms a protective film on the rubbing surfaces which is composed of BN, Fe2O3, polyoxyethylene ether and N-containing organic compounds. The inorganic and organic protective films in the metal surface effectively improve the antiwear ability of the base stock. However, when the additive MEBE was introducted into DOS base oil which is prone to adsorbing to the metal surface because of the high polarity of DOS, it influences the compactness of the film formed by the DOS, resulting in weak antiwear property. Copyright © 2016 John Wiley & Sons, Ltd.

Lanthanum fluoborate modified by oleylamine [denoted as La(BF4)3-OA] was synthesized as a potential lubricant additive by direct precipitation method with sodium tetrafluoroborate and lanthanum nitrate [La(NO3)3] as the staring materials and oleylamine (OA) as the surface-modifying agent in distilled water-ethanol mixed solvent. The effects of reaction temperature, OA to La(NO3)3 ratio, and surfactant cetyltrimethyl ammonium bromide on the size and shape of as-synthesized La(BF4)3-OA were investigated. The crystalline structure and morphology of as-obtained La(BF4)3-OA were characterized by X-ray diffraction, transmission electron microscopy, Fourier transform infrared spectrometry, and X-ray photoelectron spectroscopy. Moreover, the tribological properties of La(BF4)3-OA as an additive in dioctyl sebacate, a synthetic ester, were evaluated with a four-ball machine, and the worn surfaces of the steel balls were analyzed with a field emission scanning electron microscope equipped with an energy dispersive spectrometer accessory. It was found that the as-synthesized La(BF4)3-OA exhibits disk-like nanoflake shape and have a diameter of 10–45 nm, depending on varying synthetic conditions. As-synthesized La(BF4)3-OA as an additive in DIOS possesses excellent antiwear and friction-reduction performance for the steel–steel pair, which is because the as-synthesized additive simultaneously contain tribologically active elements La, B, and F that facilitate the formation of a boundary lubricating and protecting film on sliding steel surfaces thereby avoiding direct contact of the steel–steel pair and significantly reducing the friction and wear. Copyright © 2016 John Wiley & Sons, Ltd.

1,3,5-Tris(phenylamino) benzene and a series of its substitution derivatives were synthesized. The structure of the as-synthesized products was confirmed by nuclear magnetic resonance spectroscopy and high resolution mass spectra. Moreover, the antioxidation behavior of 1,3,5-tris(phenylamino) benzene and its substitution derivatives as antioxidants in several ester oils was evaluated by a rotary oxygen bomb test and pressurized differential scanning calorimetry, while theoretical calculations were conducted to examine their antioxidation mechanism. It was found that 1,3,5-tris(phenylamino) benzene exhibits better antioxidation ability at elevated temperature (150 and 210 °C) than commonly used commercial antioxidant diphenylamine. In the meantime, the substitution groups exhibit significant effects on the antioxidation behavior of 1,3,5-tris(phenylamino) benzene and its derivatives. This is because the substituents result in changes in the molecular structure and electronic effect of the as-synthesized p...

Durable non-wetting surfaces require high surface roughness on the nano- or micrometer scale, which is inherently fragile and easily removed by an external force. Elastic materials have potential advantages for constructing superhydrophobic surfaces with abrasion resistance since after friction or force deformation they often rebound to their original structure rather than undergoing degradation. Here we present a large-scale fabrication of free-standing silicone monoliths with a stable Cassie–Baxter state under mechanical stress cycles. The obtained elastic silicone retains excellent mechanical durability with constant super liquid-repellent after high external pressure, knife-scratch, and abrasion cycles with sandpaper. Furthermore the obtained silicone demonstrates high tolerance to continuous contact with extremely corrosive solutions, and also shows self-cleaning properties in air or under oil.

Oleic acid (OA) modified ZnO nanoparticles with an average size of 4.04 nm were prepared via a facile in situ one-step route. The as-prepared ZnO nanoparticles were characterized by X-ray diffraction, transmission electron microscopy, and Fourier transform infrared spectroscopy. The light-absorbing performance and thermal stability of the as-prepared ZnO nanoparticles were evaluated by ultraviolet-visible light spectrophotometry and thermogravimetric analysis, and their tribological behaviour as the lubricant additive in poly-alpha olefin (PAO) and diisooctyl sebacate (DIOS) base oils was evaluated with a four-ball machine. The surface morphology of the wear scar was observed with a scanning electron microscope and a three-dimensional optical profiler, and the element composition of the wear scar was determined by energy dispersive spectrometry. It was found that the surface-capping of ZnO nanoparticles by OA helps to greatly increase their dispersibility and thermal stability. In the meantime, OA-modified ZnO nanoparticles can effectively improve the antiwear and friction-reducing abilities as well as the load-carrying capacity of the base oils, which is due to the formation of a tribofilm in association with the tribo-sintering and/or adsorption of the additives on the rubbed steel surfaces. Furthermore, the friction-reducing and antiwear performances of the as-prepared ZnO nanoparticles as lubricating oil additives seem to be closely related to the polarity of the base oils. Namely, the OA-modified ZnO additive exhibits better tribological behaviour in apolar PAO than in polar DIOS.

Silver nanowires (AgNWs) with varied diameters were synthesized by a facile and efficient one-pot polyol method. The effects of reaction conditions on the morphology of the as-prepared AgNWs as well as the transmittance and optoelectronic performance of the transparent conducting films made of AgNWs were investigated. Findings indicate that each run of the reaction of the established synthesis protocol can provide more than 10 g of AgNWs, and the dynamic balance between the reduction of Ag+ (yielding Ag0) and the formation of AgCl nanocubes has an important effect on the yield and morphology of AgNWs. Based on an appropriate adjustment of the reaction conditions, the average diameter of AgNWs can be adjusted in the range of 40–110 nm while the yield of one-dimensional nanostructures in the products is as much as 95%. Furthermore, the as-synthesized AgNWs can be easily spin-coated onto polyethylene glycol terephthalate substrate to afford transparent conducting films with a transmittance as high as 87% and a sheet resistivity below 70 Ω sq−1, which demonstrates that the present synthesis strategy could be of special significance for the commercial preparation and application of silver nanowires as an alternative to commercial indium tin oxide film.