Ultrasensitive and Green Bubbling Extraction Strategies: An Extensible Solvent-Free Re-Enrichment Approach for Ultratrace Pollutants in Aqueous Samples.

Ultratrace organic pollutants in the environment pose severe threats to human health; hence, their accurate detection is essential. In this study, we develop a secondary solvent-free enrichment strategy based on bubbling extraction (BE). Especially, we used BE solid-phase microextraction and BE carbon nanotube paper absorption to capture aerosols from a liquid water surface, desorb analytes, and analyze the analytes using mass spectrometry. The application of a solvent-free enrichment strategy helps overcome technical challenges in implementing BE technology, including reproducibility, quantification, and sensitivity. This approach objectively demonstrates the enrichment efficiency of BE, resulting in improved mass spectrometry response and quantification. It effectively tackles the difficulties in detecting and quantifying ultratrace environmental pollutants in mass spectrometric analysis. The present study successfully conducted a quantitative analysis of 16 polycyclic aromatic hydrocarbons and 7 antibiotics in 48 environmental water samples. This strategy proved effective in detecting the presence and distribution of polar and nonpolar environmental pollutants in rivers and lakes. Moreover, this strategy has several advantages, such as ultrahigh sensitivity at the femtograms per liter level, good greenness, multiplexed quantitation, low sample consumption, and ease of operation. Overall, the utilization of the ultrasensitive and environmentally friendly BE approach presents a reliable and adaptable method for the identification of ultratrace environmental pollutants in water specimens, thereby enabling early monitoring of pollutant levels.

High-Performance Electrocatalytic Reduction of Nitrite to Ammonia under Ambient Conditions on a FeP@TiO2 Nanoribbon Array.

Electrochemical nitrite (NO2-) reduction is recognized as a promising strategy for synthesizing valuable ammonia (NH3) and degrading NO2- pollutants in wastewater. The six-electron process for the NO2- reduction reaction is complex and necessitates a highly selective and stable electrocatalyst for efficient conversion of NO2- to NH3. Herein, a FeP nanoparticle-decorated TiO2 nanoribbon array on a titanium plate (FeP@TiO2/TP) is proposed as an efficient catalyst for NH3 production under ambient conditions. In 0.1 M NaOH with 0.1 M NO2-, such a FeP@TiO2/TP affords a large NH3 yield of 346.6 µmol h-1 cm-2 and a high Faradaic efficiency of 97.1%. Additionally, it demonstrates excellent stability and durability during long-term cycling tests and electrolysis experiments.

Selective reduction of nitrite to nitrogen by polyaniline-carbon nanotubes composite at neutral pH.

The selective reduction of nitrite (NO2-) to nitrogen by chemical reductant is a desirable strategy to remove NO2- from polluted water and wastewater. However, the residue and reuse of chemical reductant are two main issues to be addressed. Herein, a novel polyaniline-carbon nanotubes composite (PANI-CNTs) was developed by in-situ polymerization to selectively reduce NO2- to nitrogen gas (N2). The used PANI-CNTs could be reused after regeneration with NaBH4. The PANI-CNTs could reduce NO2- with 93.9% N2 selectivity at initial pH of 6.8. The NO2- removal efficiency only decreased by 12.08% after five cycles of reduction/regeneration. The interconversion between imine nitrogen (-N) and amine nitrogen (-NH-) groups induced the chemical reduction of NO2- and regeneration of PANI-CNTs. PANI-CNTs exhibited an excellent performance for the removal of NO2- in the presence of competitive ions and in actual water and wastewater samples. This new PANI-CNTs composite may have great potential for water purification and wastewater denitrification.

A metal-organic framework (MOF) built on surface-modified Cu nanoparticles eliminates tumors via multiple cascading synergistic therapeutic effects.

Tumors produce a hypoxic environment that greatly influences cancer treatment, and conventional chemotherapeutic drugs cannot selectively accumulate in the tumor region because of the lack of a tumor targeting mechanism, causing increased systemic toxicities and side effects. Hence, designing and developing new nanoplatforms that combine multimodal therapeutic regimens is essential to improve tumor therapeutic efficacy. Herein, we report the synthesis of ultrafine Cu nanoparticles loaded with a drug combination of cisplatin (Pt) and 1-methyl-d-tryptophan (1-MT) and externally coated with 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin (TCPP) photosensitizer, polydopamine (PDA) and CaO2 of MIL-101(Fe) as a new nanoplatform (Cu@MIL-101@PMTPC). The nanoplatform synergistically combined chemodynamic therapy (CDT), photodynamic therapy (PDT), and immunochemotherapy. The Fe3+ in MIL-101(Fe) and the surface Cu nanoparticles exhibited strong ability to consume intracellular glutathione (GSH), thereby generating a Fenton-like response in the tumor microenvironment (TME) with substantial peroxidase (POD)-like and superoxide dismutase (SOD)-like activities. In this design, we used the indoleamine 2,3-dioxygenase (IDO) inhibitor 1-MT to overcome chemotherapy-induced immune escape phenomena including enhanced CD8+ and CD4+ T cell expression, interferon-gamma (IFN-γ) and tumor necrosis factor-alpha (TNF-α) production, and accelerated immunogenic cell death. The targeted release of cisplatin loaded into Cu@MIL-101@PMTPC also reduced toxic side effects of chemotherapy. TCPP generated a large amount of singlet oxygen (1O2) upon specific laser irradiation to effectively kill tumor cells. CaO2 on the outer layer generated oxygen (O2) and hydrogen peroxide (H2O2) to ameliorate hypoxia in the tumor microenvironment, enhance the PDT effect, and provide a continuous supply of H2O2 for the Fenton-like reaction. Thus, this nanocarrier platform exhibited a powerful chemodynamic, photodynamic, and immunochemotherapeutic cascade, providing a new strategy for cancer treatment.

Zn-Co metal organic frameworks coated with chitosand and Au nanoparticles for chemo-photothermal-targeted combination therapy of liver cancer.

The toxic effects of chemotherapy drugs on normal tissues are still a major limiting factor in cancer treatment. In this paper, we report a metal-organic framework (Zn-Co ZIF) with chitosan-coated outer layer as a carrier for the drug adriamycin hydrochloride (DOX), a treatment for liver cancer, as a novel anti-cancer nanodrug-enhanced carrier. Gold nanoparticles, a good photothermal conversion agent, were combined with the target SH-RGD during surface functionalisation to prepare Zn-Co ZIF@DOX-CS-Au-RGD (ZD-CAR), a nanoplatform with good photothermal conversion properties and targeting for combined liver cancer therapy. ZD-CAR was developed after RGD accurately targeted the tumour and entered the tumour microenvironment (TME), it cleaves and releases the liver cancer therapeutic agent (DOX) in a weak acidic environment to effectively kill tumour cells. The metal skeleton cleavage releases Co2+, which catalyzes the production of oxygen from H2O2 to alleviate the tumour hypoxic environment. The dissolved oxygen could reach 14 mg/L after adding 80 mg/mL of ZD-CAR. Meanwhile, gold nanoparticles could convert light energy into heat energy under 808 NIR irradiation to induce local superheating and kill tumour cells. In summary, this study developed a nanoplatform that combines chemo-photothermal-targeted therapy. It has shown good therapeutic effeciency in cellular experiments and performance tests and has promising applications in anti-cancer therapy.

Alginate/chitosan modified immunomodulatory titanium implants for promoting osteogenesis in vitro and in vivo.

The essentiality of macrophages for biomaterial-mediated osteogenesis has been increasingly recognized. However, it is still unclear what is the specific role and molecular mechanisms of macrophages and material properties in the regulation of osteogenesis. As an interdisciplinary field exploring the cross-talk between immune and skeletal systems, osteoimmunology has shifted the perspective of bone substitute materials from immunosuppressive materials to immunomodulatory materials. To fabricate an immunomodulatory Ti implant, alginate/chitosan multilayer films were fabricated on the surface of titania nanotubes (TNTs) to control the release of an anti-inflammatory cytokine interleukin (IL)-4 according to our previous work. The osteogenic effects and regulation mechanisms of the immunomodulatory Ti implants were investigated in vitro in different BMSCs culture modes. Alginate/chitosan multilayer-coated samples (with or without IL-4 loading) showed better direct osteogenic ability than TNTs by promoting biomineralization and up-regulating osteogenic gene expression (BMP1α, ALP, OPN, OCN) of BMSCs. Notably, material-induced macrophage polarization, M1 and M2, enhanced early and mid-stage osteogenesis of BMSCs via distinct pathways: M1 activated both BMP6/SMADs and Wnt10b/ß-catenin pathways; while M2 activated TGF-ß/SMADs pathway. Material surface properties dominated in regulating late osteogenesis probably due to the surface chemical composition (alginate, chitosan and Ca2+, etc.). Due to synergistic effects of material-induced inflammatory microenvironment and material surface properties, IL-4-loaded samples exhibited superior osteogenic capability through co-activation of three signaling pathways. The in vivo studies in rat bone defect model revealed that IL-4-loaded immunomodulatory implants successfully achieved macrophage phenotypic transition from pro-inflammatory M1 to anti-inflammatory M2 and subsequently improved new bone formation.

ZnO nanoparticles stimulate oxidative stress to induce apoptosis of B16F10 melanoma cells:In vitroandin vivostudies.

Melanoma is one of the most aggressive skin cancers. However, there remain many limitations in the current clinical treatments of it. Zinc oxide nanoparticles (ZnO NPs) have been considered to be a promising antitumor drug due to their excellent biocompatibility, biodegradability and biofunctionality. In this study, we prepared spherical ZnO NPs with an average diameter of less than 10 nm by a simple chemical method. According to thein vitrocytotoxicity assay, ZnO NPs in a certain concentration range (20-35µg ml-1) showed significant cytotoxicity to B16F10 melanoma cells, while having little effect on the viability of 3T3L1 fibroblasts. When cultured with B16F10 melanoma cells, ZnO NPs induced the generation of reactive oxygen and mitochondrial superoxide through the release of Zn2+, leading to oxidative stress in the cells, further reducing the mitochondrial membrane potential and decreasing the number of mitochondrial cristae. Furthermore, damaged mitochondria induced the release of apoptosis factors to promote cell apoptosis. FITC-Annexin V/propidium iodide double staining assay was used to analyze different apoptosis stages of B16F10 cells induced by ZnO NPs. A polymer hydrogel (Gel-F127-ZnO NPs) with Pluronic F127 as the carrier of ZnO NPs was fabricated for evaluating the antitumor effect of ZnO NPsin vivo. Thein vivoexperiment indicated that the tumor recurrence was significantly inhibited in tumor-bearing mice after treated with Gel-F127-ZnO NPs. Conclusively, ZnO NPs showed a strong antitumor effect bothin vitroandin vivo.

Online Scavenging of Trace Analytes in Complex Matrices for Fast Analysis by Carbon Dioxide Bubbling Extraction Coupled with Gas Chromatography-Mass Spectrometry.

Carbon dioxide (CO2) microbubbles can selectively enrich organic solutes from sea spray aerosols. Common bubbling extractions are normally followed by off-line separation/detection through methods such as mass spectrometry, chromatography, and spectroscopy. However, it is necessary to establish extractions with online separation and identification systems to improve efficiency and minimize sample loss. In this study, CO2 is used to form microbubbles in the sample solution, and trace analytes in the solution are transported to the gas phase by bubble bursting. Analytes at the liquid-gas interface are directly released into the trapping device, followed by thermal desorption for gas chromatography-mass spectrometry. For polycyclic aromatic hydrocarbons, the dependence of the extraction efficiency on various parameters has been analyzed. The method reported here provides high efficiency and minimizes the loss of trace volatiles with a better signal strength and signal-to-noise ratio than other gases. These features make the proposed method a rapid method to detect and quantify volatile/semivolatile analytes in complex liquid matrices. In addition to the preconcentration of organics, metal ions, and inorganic anions, a noticeable decrease of metal-organic compounds in the aqueous solution was shown for the first time. We finally propose a simple model of chemical partitioning in CO2 bubbling extraction of liquid samples for guiding online monitoring of trace analytes in real-world samples.

Influence of silver speciation on the inflammatory regulation of AgNPs anchoring onto titania nanotubes.

AgNPs were immobilized on titania nanotubes (TNT) by chelation of polydopamine (PD) to generate a TNT/PD/AgNPs (TPAS) via a simple dipping method. The inflammatory regulation of the TPAS coating were investigated. To gain a deep insight into the transformation of AgNPs in macrophages, a cation exchange reaction was introduced for speciation analysis of AgNPs and Ag+ by inductively coupled plasma-mass spectrometry. Owing to the magic signal amplification strategy, the trace AgNPs and Ag+ in release media and even in macrophages were easily detected. In simulated inflammatory microenvironment, M1 macrophages promoted the cell-responsive release of Ag+ from TPAS at 3 d, which dampened inflammation. Then, macrophages reduced Ag+ by intracellular metabolites, leading to the formation of new AgNPs in cells. This study give a new sight for discovering the inflammatory regulation mechanism of silver containing biomaterials.

N,N-Dimethyl-4-[(E)-phenyl-imino-meth-yl]aniline.

The title compound, C(15)H(16)N(2), contains two aromatic rings linked through an imino group. The mol-ecule exhibits an E configuration with respect to the C=N bond. The dihedral angle between the aromatic rings is 61.96 (1)°.

E-[4-(ß-d-Allopyranos-yloxy)phen-yl]-1-(4-chloro-phen-yl)prop-2-enone ethanol solvate.

The title compound, C(21)H(21)ClO(7)·C(2)H(5)OH was synthesized by the condensation reaction between helicid [systematic name: 4-(ß-d-allopyranos-yloxy)benzaldehyde] and 4-chloro-aceto-phen-one in ethanol. In the mol-ecular structure, the pyran-oside ring adopts a chair conformation. In the crystal structure, the molecules are linked by inter-molecular O-H⋯O hydrogen bonds involving the OH groups from the pyran-oside unit and from the ethanol solvent mol-ecule.

Alginate/chitosan multilayer films coated on IL-4-loaded TiO2 nanotubes for modulation of macrophage phenotype.

Macrophage phenotype conversion is crucial for improving post-traumatic angiogenesis and tissue repair. Biomaterials with the ability of skewing macrophage phenotype have attracted widespread attention in the field of tissue engineering. The aim of this study was to transform macrophage phenotype by a three-step process; anodizing, drug loading and coating with polyelectrolyte multilayer (PEM) films. Interleukin (IL)-4, an anti-inflammatory cytokine, was loaded into titania nanotubes (TNTs) on the titanium surface. Subsequently, sodium alginate (ALG) and chitosan (CS) were alternately assembled onto IL-4-loaded TNTs and cross-linked with genipin/calcium chloride, finally forming cross-linked PEM films. The IL-4 release profile and cellular immune response of the modified surface was investigated. In the simulated biological solution, only 20% of IL-4 were detected in the first 3 days, with a sustained release of approximately 5 ng over 10 days. The results of gene expression and protein secretion in macrophages indicated that IL-4-loaded PEM films significantly attenuated the inflammatory activity of macrophages at the later stage through down-regulating the mRNA and protein levels of inflammatory markers. In summary, IL-4 was controlled released from the cross-linked PEM films deposited on the nanotubes, leading to the temporal conversion of macrophage phenotype.

Alginate/chitosan multilayer films coated on IL-4-loaded TiO2 nanotubes for modulation of macrophage phenotype.

Macrophage phenotype conversion is crucial for improving post-traumatic angiogenesis and tissue repair. Biomaterials with the ability of skewing macrophage phenotype have attracted widespread attention in the field of tissue engineering. The aim of this study was to transform macrophage phenotype by a three-step process; anodizing, drug loading and coating with polyelectrolyte multilayer (PEM) films. Interleukin (IL)-4, an anti-inflammatory cytokine, was loaded into titania nanotubes (TNTs) on the titanium surface. Subsequently, sodium alginate (ALG) and chitosan (CS) were alternately assembled onto IL-4-loaded TNTs and cross-linked with genipin/calcium chloride, finally forming cross-linked PEM films. The IL-4 release profile and cellular immune response of the modified surface was investigated. In the simulated biological solution, only 20% of IL-4 were detected in the first 3 days, with a sustained release of approximately 5 ng over 10 days. The results of gene expression and protein secretion in macrophages indicated that IL-4-loaded PEM films significantly attenuated the inflammatory activity of macrophages at the later stage through down-regulating the mRNA and protein levels of inflammatory markers. In summary, IL-4 was controlled released from the cross-linked PEM films deposited on the nanotubes, leading to the temporal conversion of macrophage phenotype.

Ethoxy-carbonyl-methyl ursolate.

The title compound, C(34)H(54)O(5), was synthesized by the reaction of ursolic acid with ethyl chloro-acetate in the presence of DMA. All six-membered rings of the penta-cyclic triterpene skeleton adopt chair conformations. In the crystal structure, mol-ecules are linked by inter-molecular O-H⋯O hydrogen-bond inter-actions, forming zigzag chains along the c axis.

Macrophage phenotype switch by sequential action of immunomodulatory cytokines from hydrogel layers on titania nanotubes.

Inflammatory response occurring between tissues and implants after implantation has attracted increasing attention because it can cause local tissue necrosis and even implant failure. Macrophages play a key role in all stages of inflammation. Pro-inflammatory (M1) and anti-inflammatory (M2) macrophages comprise two main phenotypes and the switch from M1 to M2 at specific time points is important for wound healing and tissue regeneration. Therefore, we hypothesized that biomaterial systems capable of facilitating macrophage phenotype switching should attenuate inflammation and enhance healing. To this end, a system of double hydrogel layers on titania nanotubes (TNT) was prepared as reservoir to modulate the release of interleukin-4 (IL-4) and interferon-γ (IFN-γ). In this system, IL-4, an anti-inflammatory cytokine, was loaded in TNT and IFN-γ, a pro-inflammatory cytokine, was located between two hydrogel layers of chitosan/ß-glycerophosphate disodium and carboxymethyl chitosan/genipin. IFN-γ released rapidly in 3 days, whereas IL-4 exhibited a sustained release profile. In culture with mesenchymal stem cells and macrophages, this system displayed good cytocompatibility and significantly promoted cell proliferation. Macrophage phenotype switch was determined by ELISA, FACS and PCR. The results manifested that IFN-γ released from the system stimulated switching of macrophages to M1 in 3 days, whereas sustained release of IL-4 polarized macrophages to M2 after 4 days. This system can modulate macrophage phenotype switching from M1 to M2 by sequential action of the two cytokines, and might be used to research immune response between tissues and implants. The present study also provided a novel strategy for designing functional biomaterials.