Polymer Micelles vs Polymer-Lipid Hybrid Vesicles: A Comparison Using RAW 264.7 Cells.

Bottom-up synthetic biology aims to integrate artificial moieties with living cells and tissues. Here, two types of structural scaffolds for artificial organelles were compared in terms of their ability to interact with macrophage-like murine RAW 264.7 cells. The amphiphilic block copolymer poly(cholesteryl methacrylate)-block-poly(2-carboxyethyl acrylate) was used to assemble micelles and polymer-lipid hybrid vesicles together with 1,2-dioleoyl-sn-glycero-3-phosphocholine or 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) lipids in the latter case. In addition, the pH-sensitive fusogenic peptide GALA was conjugated to the carriers to improve their lysosomal escape ability. All assemblies had low short-term toxicity toward macrophage-like murine RAW 264.7 cells, and the cells internalized both the micelles and hybrid vesicles within 24 h. Assemblies containing DOPE lipids or GALA in their building blocks could escape the lysosomes. However, the intracellular retention of the building blocks was only a few hours in all the cases. Taken together, the provided comparison between two types of potential scaffolds for artificial organelles lays out the fundamental understanding required to advance soft material-based assemblies as intracellular nanoreactors.

Mitochondria Encapsulation in Hydrogel-Based Artificial Cells as ATP Producing Subunits.

Artificial cells (ACs) aim to mimic selected structural and functional features of mammalian cells. In this context, energy generation is an important challenge to be addressed when self-sustained systems are desired. Here, mitochondria isolated from HepG2 cells are employed as natural subunits that facilitate chemically driven adenosine triphosphate (ATP) synthesis. The successful mitochondria isolation is confirmed by monitoring the preserved inner membrane potential, the respiration, and the ATP production ability. The encapsulation of the isolated mitochondria in gelatin-based hydrogels results in similar initial ATP production compared to mitochondria in solution with a sustained ATP production over 24 h. Furthermore, luciferase is coencapsulated with the mitochondria in gelatin-based particles to create ACs and employ the in situ produced ATP to drive the catalytic conversion of d-luciferin. The coencapsulation of luciferase-loaded liposomes with mitochondria in gelatin-based hydrogels is additionally explored where the encapsulation of mitochondria and liposomes resulted in clustering effects that are likely contributing to the functional performance of the active entities. Taken together, mitochondria show potential in cell mimicry to facilitate energy-dependent processes.

Enzyme Mimic Facilitated Artificial Cell to Mammalian Cell Signal Transfer.

Catalyzing biochemical reactions with enzymes and communicating with neighboring cells via chemical signaling are two fundamental cellular features that play a critical role in maintaining the homeostasis of organisms. Herein, we present an artificial enzyme (AE) facilitated signal transfer between artificial cells (ACs) and mammalian HepG2 cells. We synthesize metalloporphyrins (MPs) based AEs that mimic cytochrome P450 enzymes (CYPs) to catalyze a dealkylation and a hydroxylation reaction, exemplified by the conversion of resorufin ethyl ether (REE) to resorufin and coumarin (COU) to 7-hydroxycoumarin (7-HC), respectively. The AEs are immobilized in hydrogels to produce ACs that generate the two diffusive fluorophores, which can diffuse into HepG2 cells and result in dual intracellular emissions. This work highlights the use of AEs to promote AC to mammalian signal transfer, which opens up new opportunities for integrating the synthetic and living world with a bottom-up strategy.

Giant Concentric Metallosupramolecule with Aggregation-Induced Phosphorescent Emission.

Fluorescent metallosupramolecules have received considerable attention due to their precisely controlled dimensions as well as the tunable photophysical and photochemical properties. However, phosphorescent analogues are still rare and limited to small structures with low-temperature phosphorescence. Herein, we report the self-assembly and photophysical studies of a giant, discrete metallosupramolecular concentric hexagon functionalized with six alkynylplatinum(II) bzimpy moieties. With a size larger than 10 nm and molecular weight higher than 26 000 Da, the assembled terpyridine-based supramolecule displayed phosphorescent emission at room temperature. Moreover, the supramolecule exhibited enhanced aggregation-induced phosphorescent emission compared to the ligand by tuning the aggregation states through intermolecular interactions and significant enhancement of emission to CO2 gas.

Hard Fusion Based Spectrum Sensing over Mobile Fading Channels in Cognitive Vehicular Networks.

An explosive growth in vehicular wireless applications gives rise to spectrum resource starvation. Cognitive radio has been used in vehicular networks to mitigate the impending spectrum starvation problem by allowing vehicles to fully exploit spectrum opportunities unoccupied by licensed users. Efficient and effective detection of licensed user is a critical issue to realize cognitive radio applications. However, spectrum sensing in vehicular environments is a very challenging task due to vehicle mobility. For instance, vehicle mobility has a large effect on the wireless channel, thereby impacting the detection performance of spectrum sensing. Thus, gargantuan efforts have been made in order to analyze the fading properties of mobile radio channel in vehicular environments. Indeed, numerous studies have demonstrated that the wireless channel in vehicular environments can be characterized by a temporally correlated Rayleigh fading. In this paper, we focus on energy detection for spectrum sensing and a counting rule for cooperative sensing based on Neyman-Pearson criteria. Further, we go into the effect of the sensing and reporting channel conditions on the sensing performance under the temporally correlated Rayleigh channel. For local and cooperative sensing, we derive some alternative expressions for the average probability of misdetection. The pertinent numerical and simulating results are provided to further validate our theoretical analyses under a variety of scenarios.

Fluorescent Cross-Linked Supramolecular Polymer Constructed by Orthogonal Self-Assembly of Metal-Ligand Coordination and Host-Guest Interaction.

A new host molecule consists of four terpyridine groups as the binding sites with zinc(II) ion and a copillar[5]arene incorporated in the center as a spacer to interact with guest molecule was designed and synthesized. Due to the 120 ° angle of the rigid aromatic segment, a cross-linked dimeric hexagonal supramolecular polymer was therefore generated as the result of the orthogonal self-assembly of metal-ligand coordination and host-guest interaction. UV/Vis spectroscopy, (1) H NMR spectroscopy, viscosity and dynamic light-scattering techniques were employed to characterize and understand the cross-linking process with the introduction of zinc(II) ion and guest molecule. More importantly, well-defined morphology of the self-assembled supramolecular structure can be tuned by altering the adding sequence of the two components, that is, the zinc(II) ion and the guest molecule. In addition, introduction of a competitive ligand suggested the dynamic nature of the supramolecular structure.

Highly selective detection of 2,4,6-trinitrophenol and Cu(2+) ions based on a fluorescent cadmium-pamoate metal-organic framework.

A luminescent cadmium-pamoate metal-organic framework, [Cd2 (PAM)2 (dpe)2 (H2 O)2 ]⋅0.5(dpe) (1), has been synthesized under hydrothermal conditions by using π-electron-rich ligands 4,4'-methylenebis(3-hydroxy-2-naphthalenecarboxylic acid) (H2 PAM) and 1,2-di(4-pyridyl)ethylene (dpe). Its structure is composed of both mononuclear and dinuclear Cd(II) building units, which are linked by the PAM and dpe ligands, resulting in a (4,8)-connected 3D framework. The π-conjugated dpe guests are located in a 1D channel of 1. The strong emission of 1 could be quenched efficiently by trace amounts of 2,4,6-trinitrophenol (TNP), even in the presence of other competing analogues such as 4-nitrophenol, 2,6-dinitrotoluene, 2,4-dinitrotoluene, nitrobenzene, 1,3-dinitrobenzene, hydroquinone, dimethylbenzene, and bromobenzene. The high sensitivity and selectivity of the fluorescence response of 1 to TNP shows that this framework could be used as an excellent sensor for identifying and quantifying TNP. In the same manner, 1 also exhibits superior selectivity and sensitivity towards Cu(2+) compared with other metal ions such as Zn(2+) , Mn(2+) , Mg(2+) , K(+) , Na(+) , Ni(2+) , Co(2+) , and Ca(2+) . This is the first MOF that can serve as a dual functional fluorescent sensor for selectively detecting trace amounts of TNP and Cu(2+) .

Two bent-shaped π-organogelators: synthesis, fluorescence, self-assembly and detection of volatile acid vapours in gel films and in gel-gel states.

Two novel bent-shaped π-organogelators 6a and 6b having different terminal pyridine rings as responsive sites were designed, synthesized and fully characterized. A subtle difference in the position of the N atom at the pyridine ring greatly affected their fluorescence and gelation properties. 6b showed remarkably stronger fluorescence both in solution and in the solid state as compared to 6a. Theoretical calculation revealed a clear discrepancy in the electron distribution between them. Furthermore, driven by π­π stacking interaction and hydrophobic interaction, both 6a and 6b can gelate several organic solvents with different polarities. Rheological studies, spectroscopic tests and powder X-ray diffraction showed that 6a displayed a closer stacking mode leading to stronger gel robustness. The xerogel films of 6a and 6b were prepared and utilized to detect acid vapours. Both of them can fulfil the detection of acid vapours through a distinct fluorescence change which could be seen by the naked eye under a UV lamp, but with different sensing modes. A rare gel to gel transformation was also observed upon exposure to acid vapours accompanied by a morphological change.

Crystal structure of cell adhesion molecule nectin-2/CD112 and its binding to immune receptor DNAM-1/CD226.

The nectin and nectin-like molecule (Necl) family includes important cell adhesion molecules (CAMs) characterized by their Ig-like nature. Such CAMs regulate a broad spectrum of cell-cell interactions, including the interaction between NK cells and cytotoxic T lymphocytes (CTLs) and their target cells. CAM members nectin-2 (CD112) and Necl-5 (CD155) are believed to form homodimers (for nectin-2) or heterodimers in their functions for cell adhesion, as well as to interact with immune costimulatory receptor DNAX accessory molecule 1 (DNAM-1) (CD226) to regulate functions of both NK and CTL cells. However, the structural basis of the interactive mode of DNAM-1 with nectin-2 or Necl-5 is not yet understood. In this study, a soluble nectin-2 Ig-like V-set domain (nectin-2v) was successfully prepared and demonstrated to bind to both soluble ectodomain and cell surface-expressed full-length DNAM-1. The 1.85-Å crystal structure of nectin-2v displays a perpendicular homodimer arrangement, revealing the homodimer characteristics of the nectin and Necls. Further mutational analysis indicated that disruption of the homodimeric interface of nectin-2v led to a failure of the homodimer formation, as confirmed by crystal structure and biochemical properties of the mutant protein of nectin-2v. Interestingly, the monomer mutant also loses DNAM-1 binding, as evidenced by cell staining with tetramers and surface plasmon resonance assays. The data indicate that interaction with DNAM-1 requires either the homodimerization or engagement of the homodimeric interface of nectin-2v. These results have implications for immune intervention of tumors or autoimmune diseases in the DNAM-1/nectin-2-dependent pathway.

The role of p38 MAPK in acute paraquat-induced lung injury in rats.

CONTEXT: Paraquat (PQ; 1,1'-dimethyl-4,4'-bipyridinium dichloride) is highly toxic and accounts for a large proportion of the herbicide poisonings seen in clinic. The major cause of mortality is respiratory failure. The p38 mitogen-activated protein kinase (MAPK) signal transduction pathway coordinates various cellular stress responses that have been shown to participate in the pathogenesis of PQ-induced lung injury. OBJECTIVE: To evaluate the effect of the specific p38 MAPK inhibitor SB203580 on PQ-induced lung injury and cytokine secretion. METHODS: In groups of 24, rats were treated with PQ, PQ and SB203580 (SB + PQ), SB203580 alone (SB) or normal saline (control group). Six rats from each group were euthanized at 1, 3, 5 or 7 d. Pathology of lung specimens was scored through hematoxylin and eosin staining. Edema in the lung was quantified from wet-to-dry weight ratios. p38 and p-p38MAPK proteins were measured via electrochemiluminescent Western blots. tumor necrosis factor (TNF)-alpha and interleukin-1 beta (IL-1ß) concentrations in lung specimens and bronchoalveolar lavage fluid (BALF) were quantified via enzyme-linked immunosorbent assay. RESULTS: The mortality rate of the SB + PQ group (16.7%) was significantly lower than that of the PQ group (33.3%; p < 0.05). The PQ group had significantly higher pulmonary histology scores, wet-to-dry weight ratios and phosphorylated p-p38 MAPK levels, as well as higher IL-1ß and TNF-alpha levels in BALF and lung tissues, that did the SB + PQ and control groups (p < 0.05, all). CONCLUSION: The data suggest that the p38 MAPK signaling pathway has an important role in regulating the production of IL-1ß and TNF-alpha in PQ-induced lung injury in rats.

Co-encapsulation of granzyme B and perforin in nanocapsules for tumour therapy: biomimicking immune cells.

Granzyme B (GrB)-based immunotherapy is of interest for cancer treatment. However, insufficient cellular uptake and a lack of targeting remain challenges to make use of GrB for solid tumour therapy. As GrB induced cell death requires the help of perforin (PFN), we designed a system (nGPM) for the co-delivery of GrB and PFN. Therefore, GrB and PFN were loaded in a porous polymeric nanocapsule rich in acetylcholine analogues and matrix metalloproteinase-2 (MMP-2) responsive peptides. The neutrally charged nGPM nanocapsules showed as long circulating time and accumulated at the tumour sites. Once in the tumour the outside shell of nanocapsules became degraded by overexpressed MMP-2 proteases, resulting in the release of GrB and PFN. We found that the PFN complex formed small pores on the surface of tumour cells which allow GrB to enter the cytoplasm of tumour cells inducing cell apoptosis and tumour suppression significantly.

Surfaces Coated with Polymer Brushes Work as Carriers for Histidine Ammonia Lyase.

The immobilization of enzymes on solid supports is an important challenge in biotechnology and biomedicine. In contrast to other methods, enzyme deposition in polymer brushes offers the benefit of high protein loading that preserves enzymatic activity in part due to the hydrated 3D environment that is available within the brush structure. The authors equipped planar and colloidal silica surfaces with poly(2-(diethylamino)ethyl methacrylate)-based brushes to immobilize Thermoplasma acidophilum histidine ammonia lyase, and analyzed the amount and activity of the immobilized enzyme. The poly(2-(diethylamino)ethyl methacrylate) brushes are attached to the solid silica supports either via a "grafting-to" or a "grafting-from" method. It is found that the grafting-from method results in higher amounts of deposited polymer and, consequently, higher amounts of Thermoplasma acidophilum histidine ammonia lyase. All polymer brush-modified surfaces show preserved catalytic activity of the deposited Thermoplasma acidophilum histidine ammonia lyase. However, immobilizing the enzyme in polymer brushes using the grafting-from method resulted in twice the enzymatic activity from the grafting-to approach, illustrating a successful enzyme deposition on a solid support.

Multistage-Responsive Dual-Enzyme Nanocascades for Synergistic Radiosensitization-Starvation Cancer Therapy.

Radiotherapy is a common cancer treatment approach in clinical practice, yet its efficacy has been restricted by tumor hypoxia. Nanomaterials-mediated systemic delivery of glucose oxidase (GOx) and catalase (CAT) or CAT-like nanoenzymes holds the potential to enhance tumor oxygenation. However, they face the challenge of intermediate (hydrogen peroxide [H2 O2 ]) escape during systemic circulation if the enzyme pair is not closely placed to largely decompose H2 O2 , leading to oxidative stress on normal tissues. In the present study, a oxygen-generating nanocascade, n(GOx-CAT)C7A , constructed by strategically placing an enzymatic cascade (GOx and CAT) within a polymeric coating rich in hexamethyleneimine (C7A) moieties, is reported. During blood circulation, C7A remains predominantly non-protonated , achieving prolonged blood circulation due to its low-fouling surface. Once n(GOx-CAT)C7A reaches the tumor site, the acidic tumor microenvironment (TME) induces protonation of C7A moieties, resulting in a positively charged surface for enhanced tumor transcytosis. Moreover, GOx and CAT are covalently conjugated into close spatial proximity (<10 nm) for effective H2 O2  elimination. As demonstrated by the in vivo results, n(GOx-CAT)C7A achieves effective tumor retention and oxygenation, potent radiosensitization and antitumor effects. Such a dual-enzyme nanocascade for smart O2  delivery holds great potential for enhancing the hypoxia-compromised cancer therapies.

Sequence-dependent synergistic inhibition of human glioma cell lines by combined temozolomide and miR-21 inhibitor gene therapy.

Down-regulation of microRNA-21 (miR-21) can induce cell apoptosis and reverse drug resistance in cancer treatments. In this study, we explored the most effective schedule of the miR-21 inhibitor (miR-21i) and Temozolomide (TMZ) combined treatment in human glioma cells. Three tumor cell lines, U251 phosphatase and tensin homologue (PTEN) mutant, LN229 (PTEN wild-type), and U87 (PTEN loss of function), were subjected to evaluate the antitumor effects of deigned treatments (a predose of miR-21i for 4/8 h and then a subsequent TMZ treatment, a predose of TMZ for 4/8 h and then a subsequent miR-21i treatment, or a concomitant treatment) in vitro. A synergistic antiproliferative and proapoptotic activity was only obtained in U251 and U87 cells when a predose was administered for 4 h before the treatment of the other therapeutic agent, while the best antitumor effect in LN229 cells was achieved by using the concomitant treatment. Our data indicate that the effect of sequence and timing of administration is dependent on the PTEN status of cell lines. The best suppression effect was achieved by a maximal inhibition of STAT3 and phosphorylated STAT3, in PTEN loss of function cells. Our results reveal that both the sequence and the timing of administration are crucial in glioma combination therapy.

An ultrasensitive electrochemiluminescent sensing platform for oxygen metabolism based on bioactive magnetic beads.

Reactive oxygen species (ROS), produced during oxygen metabolism, participate in and regulate various life processes. It is of great significance to monitor ROS in biological organs to further study oxygen metabolism. Herein, an ultrasensitive sensing platform is developed with electrochemiluminescent (ECL) signalling by integrating bioactive magnetic beads (BMBs) on indium tin oxide (ITO) coated glass using a magnet. For the first time, AuNPs were successfully deposited on Fe3O4 NPs in situ by reduction of α-ketoglutaric acid (α-KG), therefore the electroactive protein, haemoglobin (Hb) or cytochrome C (Cyt C), was assembled on via covalent bonds. The protein can realize direct electron transfer (DET) and catalyse the redox of ROS, reaching a detection limit of 6.21 µM or 0.6 µM of H2O2. Also Au@Fe3O4 NPs efficiently enhanced the ECL of luminol, promoting the sensing ability for ROS. This simultaneous effect endows the platform with low LOD of ROS for 7.69 nM (Hb), or 1.97 nM (Cyt C). Finally, the feasibility and practicality of the sensing platform were verified by monitoring the ROS released from mouse myocardial tissue.

A novel Granzymes and miRNA nanocapsules co-delivery system for tumor suppression.

Granzymes-based immunotherapy for the treatment of solid tumors has gained great success and played more and more important effect in clinical studies. However, the antitumor effect of Granzymes still requires improvements owing to the cell evasion and metastasis of cancer. To overcome these limitations, synergistic combinatorial anti-tumor effect of Granzyme B (GrB) and miR-21 inhibitor (miR-21i) for breast cancer therapy through a new co-delivery system was investigated in present study. GrB was covalently bonded with miR-21i by disulfide bond and encapsulated in a nanocapsule formed byin situpolymerization of N -(3-aminopropyl) methacrylamide (APM), ethylene glycol dimethacrylate (EGDMA) and 2-Methacryloyloxyethyl phosphorylcholine (MPC). The nanocapsules possessed spherical and uniform diameter size as well as pH responsiveness in various environments. MTT and flow cytometry analysis showed that a synergistic anti-proliferation and promoting apoptosis effect was achieved when the nanocapsules were added into breast cancer cell lines. More importantly, the cell evasion ability was markedly inhibited using the nanocapusles detected through transwell invasion assay. Also thein vivoanti-tumor therapeutic efficacy of GrB-miR-21i nanocapusles was evaluated in a mouse tumor model. In conclusion, the nanocapsules for simultaneously delivery of GrB and miR-21i produce a synergistic effect in human breast cancer therapy.

N-(4-Fluoro-benz-yl)-3-nitro-pyridine-2,6-diamine.

In the title compound, C(12)H(11)FN(4)O(2), the pyridine ring is connected to a benzene ring by a -CH(2)-NH(2)- chain. The nitro group is twisted out of the pyridine ring plane [torsion angle O-N-C-C = 10.41 (10)°]. An intramolecular N-H⋯O hydrogen bond occurs. The fluoro-benzene ring is disordered over two positions [occupancy ratio = 0.59 (3):0.41 (3)]. Inter-molecular N-H⋯O and N-H⋯N hydrogen bonds stabilize the crystal structure.

Aqua-[bis-(2-ethyl-5-methyl-1H-imidazol-4-yl-κN)methane]-oxalatocopper(II) dihydrate.

In the title compound, [Cu(C(2)O(4))(C(13)H(20)N(4))(H(2)O)]·2H(2)O, the Cu(II) atom exhibits a distorted square-pyramidal geometry with the two N atoms of the imidazole ligand and the two O atoms of the oxalate ligand forming the basal plane, while the O atom of the coordinated water mol-ecule is in an apical position. The Cu(II) atom is shifted 0.232 (2) Šout of the basal plane toward the water mol-ecule. The asymmetric unit is completed by two solvent water mol-ecules. These water mol-ecules participate in the formation of an intricate three-dimensionnal network of hydrogen bonds involving the coordinated water mol-ecule and the NH groups.

Bis[bis-(2-ethyl-5-methyl-1H-imidazol-4-yl-κN)methane](nitrato-κO,O')nickel(II) nitrate.

In the title compound, [Ni(NO(3))(C(13)H(20)N(4))(2)]NO(3), the Ni(II) ion shows a distorted octa-hedral geometry formed by four N atoms from two bis-(2-ethyl-5-methyl-1H-imidazol-4-yl)methane ligands and two O atoms from a chelating nitrate anion. Three ethyl groups in the complex cation and the O atoms of the uncoordinated nitrate anion are disordered over two sets of positions [occupancy ratios of 0.52 (3):0.48 (3) and 0.63 (3):0.37 (3), respectively]. In the crystal, inter-molecular N-H⋯O hydrogen bonds connect the complex cations into a zigzag chain along [010] and further N-H⋯O hydrogen bonds between the chains and the uncoordinated nitrate anions lead to layers parallel to (100).

Dichlorido[bis-(2-ethyl-5-methyl-1H-imidazol-4-yl-κN)methane]-cobalt(II) monohydrate.

In the title compound, [CoCl(2)(C(13)H(20)N(4))]·H(2)O, the Co(II) atom lies on a mirror plane and is four-coordinated by two N atoms of the imidazole ligand and two Cl atoms in a distorted tetra-hedral arrangement. The water mol-ecule participates in the formation of hydrogen bonds, resulting in a three dimensional network involving the Cl atoms and the NH groups. The terminal C atom of the ethyl group is disordered over two sites of equal occupancy.