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We have shown previously that exposing bacteria to tetrachlorocatechol (TCC) and sodium azide (NaN3) together causes synergistic cytotoxicity in a biphasic mode. However, the underlying chemical mechanism remains unclear. In this study, an unexpected ring-contraction 3(2H)-furanone and two quinoid-compounds were identified as the major and minor reaction products, respectively; and two unusual azido-substituted chloro-O-semiquinone radicals were detected and characterized as the major radical intermediates by complementary applications of direct ESR, HPLC/ESI-Q-TOF and high-resolution MS studies with nitrogen-15 isotope-labeled NaN3. Taken together, we proposed a novel molecular mechanism for the reaction of TCC/NaN3: N3- may attack on tetrachloro-O-semiquinone radical, forming two transient 4-azido-3,5,6-trichloro- and 4,5-diazido-3,6-dichloro-O-semiquinone radicals, consecutively. The second-radical intermediate may either undergo an unusual zwitt-azido cleavage to form the less-toxic ring-contraction 3(2H)-furanone product, or further oxidize to form the more toxic quinoid-product 4-amino-5-azido-3,6-dichloro-O-benzoquinone. A good correlation was observed between the biphasic formation of this toxic quinone due to the two competing decomposition pathways of the radical intermediate and the biphasic synergism between TCC and NaN3, which are dependent on their molar-ratios. This is the first report of detection and identification of two unique azido-substituted chloro-O-semiquinone radicals, and an unprecedented ring-contraction mechanism via an unusually mild and facile zwitt-azido rearrangement.

Stabilities of cellulose Pickering emulsions are of great importance to utilize them effectively, but influenced by their complex compositions, such as, colloidal particles, oil phases and water phases. In this work, solid-liquid controllable polymerization products could obtain by adjusting cellulose nanocrystals (CNCs) concentration and vinyl acetate (VAc)-water ratio. The emulsions in zone Ӏ (w/o) and II (o/w) of the three-phase diagram were selected for researching. The polymerization emulsions in zone II illustrated the o/w ratio played a more important role than CNCs concentration in the storage stability and practicality of the polymerized emulsion; The polymer in zone Ӏ showed a large number of porous structures. This is an innovative method that different forms of target products are obtained through the guidance of three-phase diagram, which not only broadens the application field, but also applies to other Pickering emulsion systems.

Summary Synthetically trapping kinetically varied (super)structures of molecular assemblies and amplifying them to the macroscale is a promising, yet challenging, approach for the advancement of meta-stable materials. Here, we demonstrated a concerted kinetic trapping design to timely resolve a set of transient polypseudorotaxanes in solution and harness a crop of them via micro-crystallization. By installing stopper or speed bump moieties on the polymer axles, meta-stable polypseudorotaxanes with segmented cyclodextrin blocks were hierarchically amplified into crystalline networks of different crosslinking densities at mesoscale and viscoelastic hydrogels with 3D-printability in bulk. We demonstrated simultaneous 3D-printing of two polypseudorotaxane networks from one reactive ensemble and their conversion to heterogeneous polyrotaxane monoliths. Spatially programming the macroscale shapes of these heterogeneous polyrotaxanes enabled the construction of moisture-responsive actuators, in which the shape morphing originated from the different numbers of cyclodextrins interlocked in these polyrotaxane networks.

The leakage issue, low thermal conductivity and low photo-thermal conversion capacity of organic phase change material (PCMs) greatly limits their practical utilization. Herein, a novel shape-stabilized composite PCMs with enhanced thermal conductivity and superior photo-thermal conversion efficiency was fabricated by incorporating polyethylene glycol (PEG) into porous carbonized wood loaded with carbon dots (CDs). The CDs-contained supporting material was not only characterized by unique three-dimensional porous structure, but also beneficial to prevent the leakage of melted PEG during the phase change process. The underlying reason was that extra hydrogen-bonding interaction between CDs and PEG can be readily formed in addition to surface tension, capillary action. Thus, the constructed PCMs outperformed the one without CDs incorporation in terms of shape-stabilized performance. Further, the CDs-contained PCMs exhibited high thermal conductivity (0.449 W/m K), which was comparable to the PCMs using carbonized wood as single supporting material, but showing 117% higher than that of pristine PEG. More importantly, this novel supporting material fabricated by integrating carbonized wood and CDs also imparted the resultant PCMs with high photo-thermal conversion efficiency (84.4%), latent heat (112.4 J/g), thermal reliability and thermal stability, thus demonstrating great potential utilization in constructing solar water heating systems.

The development of integrated systems that mimic the multi-stage stiffness change of marine animals such as the sea cucumber requires the design of molecularly tailored structures. Herein, we used an integrated biomimicry design to fabricate a sea cucumber mimic using sidechain polypseudorotaxanes with tunable nano-to-macroscale properties. A series of polyethylene glycol (PEG)-based sidechain copolymers were synthesized to form sidechain polypseudorotaxanes with α-cyclodextrins (α-CDs). By tailoring the copolymers' molecular weights and their PEG grafting densities, we rationally tuned the sizes of the formed polypseudorotaxanes crystalline domain and the physical crosslinking density of the hydrogels, which facilitated 3D printing and the mechanical adaptability to these hydrogels. After 3D printing and photo-crosslinking, the obtained hydrogels exhibited large tensile strain and broad elastic-to-plastic variations upon α-CD (de)threading. These discoveries enabled a successful fabrication of a sea cucumber mimic, demonstrating multi-stage stiffness changes.

Many immune responses depend upon activation of NF-κB, an important transcription factor in the elicitation of a cytokine response. Here we show that N4BP1 inhibits TLR-dependent activation of NF-κB by interacting with the NF-κB signaling essential modulator (NEMO, also known as IκB kinase γ) to attenuate NEMO–NEMO dimerization or oligomerization. The UBA-like (ubiquitin associated-like) and CUE-like (ubiquitin conjugation to ER degradation-like) domains in N4BP1 mediate interaction with the NEMO COZI domain. Both in vitro and in mice, N4bp1 deficiency specifically enhances TRIF-independent (TLR2, TLR7, or TLR9-mediated) but not TRIF-dependent (TLR3 or TLR4-mediated) NF-κB activation, leading to increased production of proinflammatory cytokines. In response to TLR4 or TLR3 activation, TRIF causes activation of caspase-8, which cleaves N4BP1 distal to residues D424 and D490 and abolishes its inhibitory effect. N4bp1−/− mice also have diminished numbers of T cells in the peripheral blood. Our work identifies N4BP1 as an inhibitory checkpoint protein that must be overcome to activate NF-κB, and a TRIF-initiated caspase-8-dependent mechanism by which this is accomplished., NF-κB signalling is critical to TLR mediated cytokine release in various immune responses. Here the authors show how N4BP1 inhibits NEMO signalling and subsequent NF-κB activation and how this pathway is negatively regulated by caspase-8 cleavage of N4BP1.

We have recently found that penicillamine, a classic copper-chelating thiol-drug for Wilson's disease, can delay tetrachlorohydroquinone (TCHQ) autooxidation via a previously unrecognized redox-activity. However, its underlying molecular mechanism remains not fully understood. In this study, we found, interestingly and unexpectedly, that superoxide dismutase (SOD) can significantly shorten the delay of TCHQ autooxidation by penicillamine, but not by ascorbate; SOD can also markedly increase the yields of the oxidized form of penicillamine. Similar effects were observed with a recently-developed specific and sensitive superoxide anion radical (O2•-) probe CT-02H, which was also employed to successfully measure O2•- generated from both TCHQ and TCHQ/penicillamine systems for the first time. More importantly, addition of extra O2•- (KO2/18-crown-6) can further prolong the delaying effects by penicillamine and slow down penicillamine consumption. Taken together, an unexpected critical role of O2•- in TCHQ/penicillamine interaction was proposed: O2•- may regenerate penicillamine, thereby continuously reducing TCSQ•- to TCHQ and finally delaying TCHQ autooxidation; In contrast, if O2•- were eliminated, which can not only markedly change the reaction equilibrium, accelerate the rate of interaction, and ultimately shorten the delay of TCHQ autooxidation by penicillamine, but can also accelerate penicillamine oxidation to form its corresponding disulfide solely via redox reaction without any minor nucleophilic reaction. These findings not only further support our previously-proposed redox mechanism for the protection against TCHQ-induced cytotoxicity by penicillamine, but also reveal a new mode of action for O2•- in the inhibition of haloquinoids-induced toxicity by thiol antioxidants.

Since Ru(II) tri(polypyridyl) complexes can bind DNA in the groove, the chemistry of metallo-groove-binders has been extended to many applications such as artificial photonucleases and DNA recognizers. Here we found that the major product was N-(2-deoxy-β-D-erythro-pentofuranosyl)-spiroiminodihydantoin (dSp) when the nucleoside 2′-deoxyguanosine (dG) was exposed to the visible light irradiation of Ru(II) tri(polypyridyl) complexes including Ru(bpy)32+ (bpy = 2,2′-bipyridyl), Ru(OP)32+ (OP = 1,10-phenanthroline) and Ru(DIP)32+ (DIP = 4,7-diphenyl-1,10-phenanthroline). Interestingly, we found that in the oxidation of dsDNA the major oxidation product is 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodG) instead of dSp. The formation of dSp and 8-oxodG increased significantly in D2O and decreased markedly with the addition of NaN3. [18O]-Labeled 8-oxodG was also found to be produced more than non-labeled 8-oxodG under an 18O2 atmosphere. The above results clearly indicated that 1O2 was the major oxidant during the oxidation of both dG and dsDNA by the irradiation of Ru(II) complexes, which was further confirmed by both ESR spin-trapping and UV methods. Among the above three Ru(II) complexes, Ru(DIP)32+ is the most efficient photosensitized generator of dG oxidation products, while in the oxidation of dsDNA, Ru(bpy)32+ is the most effective. This is the first report that the irradiation of Ru(II) polypridyl complexes with visible light can induce potent oxidation of dG and ctDNA to the more mutagenic product dSp and 8-oxodG via an 1O2-mediated mechanism. These findings should provide new perspectives for future investigations on whether ubiquitous Ru(II) complexes could cause oxidatively generated DNA damage in cellular models.

Adenosine monophosphate deaminase 3 (Ampd3) encodes the erythrocyte isoform of the adenosine monophosphate (AMP) deaminase gene family. Mutations in this gene have been reported in humans, leading to autosomal-recessive erythrocyte AMP deaminase deficiency. However, the mutation is considered clinically asymptomatic. Using N-ethyl-N-nitrosourea mutagenesis to find mutations that affect peripheral lymphocyte populations, we identified 5 Ampd3 mutations (Ampd3guangdong, Ampd3carson, Ampd3penasco, Ampd3taos, and Ampd3commanche) that strongly correlated with a reduction in naive CD4+ T and naive CD8+ T-cell populations. Causation was confirmed by targeted ablation of Ampd3. Knockout mice had reduced frequencies of CD62LhiCD44lo CD4+ naive and CD8+ naive T cells. Interestingly, these phenotypes were restricted to T cells circulating in peripheral blood and were not seen in T cells from secondary lymphoid organs (lymph nodes and spleen). We found that reduction of naive T cells in the peripheral blood of Ampd3−/− mice was caused by T-cell–extrinsic factor(s), which we hypothesize to be elevated levels of adenosine triphosphate released by Ampd3-deficient erythrocytes. These findings provide an example in which disruption of an erythrocyte-specific protein can affect the physiological status of lymphocytes in peripheral blood.

The neuroretina is protected by its own defense system, that is microglia and the complement system. Under normal physiological conditions, microglial activation is tightly regulated by the neurons although the underlying mechanism remains elusive. Using published single‐cell RNA sequencing data sets, we found that immune regulatory molecules including CD200, CD47, CX3CL1, TGFβ, and complement inhibitor CD59a are expressed by various retinal neurons. Importantly, we found that photoreceptors express higher levels of CD47 and CD59a, which was further confirmed in cultured 661W cells, WERI‐Rb1 cells, and microdissected photoreceptors from human eyes. The expression of CD59a mRNA in 661W cells was upregulated by TNFα and hypoxia, whereas LPS, hypoxia, and IL‐4 upregulated CD47 mRNA expression in 661W cells. Immunofluorescence staining detected strong CD59a immunoreactivity in the outer nuclear layer, inner/outer segments, and discrete staining in ganglion cell layer (GCL), inner plexiform layer (IPL), and outer plexiform layer. The expression of CD59a in photoreceptors was increased in the detached retina, but decreased in retinas from experimental autoimmune uveoretinitis (EAU) mice. In EAU retina, CD59a was highly expressed by active immune cells. CD47 was detected in GCL, IPL, and inner nuclear layer and some photoreceptors. The expression of CD47 in photoreceptors was also increased in the detached retina but decreased in EAU retina. In a coculture system, 661W enhanced arginase‐1 and reduced IL‐6 mRNA expression in BV2 microglial cells. Our results suggest that photoreceptors express immune regulatory molecules and may have the potential to regulate immune activation in the outer retina/subretinal space under pathophysiological conditions.

Atmospheric low-temperature plasma has emerged as a promising pretreatment for lignocellulose to improve bio-refining. Herein, we investigated plasma-induced changes in the chemical structure of lignin to obtain a fundamental understanding of the plasma-lignocellulose interaction. Based on the results, plasma possesses a strong capacity to cleave C-C covalent bonds in the aliphatic region of lignin, accompanied by oxidation. Plasma treatment leads to the degradation and fragmentation of lignin. Pronounced deconstruction of β-O-4 aryl ether is observed in plasma. The relative content of β-O-4 aryl ether was reduced from the initial value of 65.1/100Ar to 58.7/100Ar for lignin from corncob and from the initial value of 72.5/100Ar to 63.8/100Ar for lignin from poplar after plasma treatment, respectively. According to the density functional theory analysis, the oxygen atom of β-O-4 aryl ether is the most likely potential reaction site and the Cβ-O covalent bond exhibits the lowest decomposition free energy (50.5 kcal mol-1), which will easily be cleaved in plasma. The dominant reaction pathway of lignin degradation is the cleavage of the Cβ-O covalent bond followed by the cleavage of the Cβ-Cα bond. We propose that this investigation is beneficial to optimize and expand the applications of plasma treatment in pretreatment of lignocellulose.

Due to its small size, easy accessibility and immune privileged environment, the eye represents an ideal target for therapeutic nucleic acids in the treatment of posterior segment ocular diseases, such as age-related macular degeneration (AMD). Among nanocarriers that can be used to achieve nucleic acid delivery, virus-like particles (VLPs) obtained from the Cowpea chlorotic mottle virus (CCMV) are an appealing platform, because of their loading capacity, ease of manufacture and amenability for functionalization. Herein, antisense oligonucleotide-loaded CCMV nanoparticles, intended for intravitreal injection, are evaluated for selective silencing of miR-23, an important target in AMD. CCMV nanoparticles loaded with anti-miR-23 locked nucleic acid and stabilized using the 3,3′-dithiobis(sulfosuccinimidyl propionate) (DTSSP) cross-linker, are assembled in vitro with a loading efficiency up to 80%. VLPs are found to be stable at 37 °C in the vitreous humor up to 24 hours. Nanoparticle cytotoxicity, cellular uptake and transfection efficacy are evaluated in endothelial cells. Selective miRNA down-regulation is achieved by the loaded CCMV VLPs both in absence and presence of Lipofectamine, with efficacies of ≈40% and more than 80%, respectively. The authors' findings pave the way for the future development of CCMV nanoparticles as oligonucleotide delivery platform to treat posterior segment ocular diseases.

The development of large pore single-crystalline covalently linked organic frameworks is critical in revealing the detailed structure-property relationship with substrates. One emergent approach is to photo-crosslink hydrogen-bonded molecular crystals. Introducing complementary hydrogen-bonded carboxylic acid building blocks is promising to construct large pore networks, but these molecules often form interpenetrated networks or non-porous solids. Herein, we introduced heteromeric carboxylic acid dimers to construct a non-interpenetrated molecular crystal. Crosslinking this crystal precursor with dithiols afforded a large pore single-crystalline hydrogen-bonded crosslinked organic framework HC OF-101. X-ray diffraction analysis revealed HC OF-101 as an interlayer connected hexagonal network, which possesses flexible linkages and large porous channels to host a hydrazone photoswitch. Multicycle Z/E-isomerization of the hydrazone took place reversibly within HC OF-101, showcasing the potential use of HC OF-101 for optical information storage.

Blood–retinal barrier (BRB) dysfunction underlies macular oedema in many sight-threatening conditions, including diabetic macular oedema, neovascular age-related macular degeneration and uveoretinitis. Inflammation plays an important role in BRB dysfunction. This study aimed to understand the role of the inflammatory cytokine IL-17A in BRB dysfunction and the mechanism involved. Human retinal pigment epithelial (RPE) cell line ARPE19 and murine brain endothelial line bEnd.3 were cultured on transwell membranes to model the outer BRB and inner BRB, respectively. IL-17A treatment (3 days in bEnd.3 cells and 6 days in ARPE19 cells) disrupted the distribution of claudin-5 in bEnd.3 cells and ZO-1 in ARPE19 cells, reduced the transepithelial/transendothelial electrical resistance (TEER) and increased permeability to FITC-tracers in vitro. Intravitreal (20 ng/1 μL/eye) or intravenous (20 ng/g) injection of recombinant IL-17A induced retinal albumin leakage within 48 h in C57BL/6J mice. Mechanistically, IL-17A induced Janus kinase 1 (JAK1) phosphorylation in bEnd.3 but not ARPE19 cells. Blocking JAK1 with Tofacitinib prevented IL-17A-mediated claudin-5 dysmorphia in bEnd.3 cells and reduced albumin leakage in IL-17A-treated mice. Our results suggest that IL-17A can damage the BRB through the activating the JAK1 signaling pathway, and targeting this pathway may be a novel approach to treat inflammation-induced macular oedema.

Haloquinones (XQs) are a group of carcinogenic intermediates of the haloaromatic environmental pollutants and newly identified chlorination disinfection byproducts (DBPs) in drinking water. The highly reactive hydroxyl radicals/alkoxyl radicals and quinone enoxy/ketoxy radicals were found to arise in XQs and H2O2 or organic hydroperoxides system, independent of transition-metal ions. However, it was not clear whether these haloquinoid carcinogens and hydroperoxides can cause oxidative DNA damage and modifications, and if so, what are the underlying molecular mechanisms. We found that 8-oxodeoxyguanosine (8-oxodG), DNA strand breaks, and three methyl oxidation products could arise when DNA was treated with tetrachloro-1,4-benzoquinone and H2O2 via a metal-independent and intercalation-enhanced oxidation mechanism. Similar effects were observed with other XQs, which are generally more efficient than the typical Fenton system. We further extended our studies from isolated DNA to genomic DNA in living cells. We also found that potent oxidation of DNA to the more mutagenic imidazolone dIz could be induced by XQs and organic hydroperoxides such as t-butylhydroperoxide or the physiologically relevant hydroperoxide 13S-hydroperoxy-9Z,11E-octadecadienoic acid via an unprecedented quinone-enoxy radical-mediated mechanism. These findings should provide new perspectives to explain the potential genotoxicity, mutagenesis, and carcinogenicity for the ubiquitous haloquinoid carcinogenic intermediates and DBPs.

Purpose: For this study we aimed to understand if retinal pigment epithelial (RPE) cells express antimicrobial peptide lysozyme as a mechanism to protect the neuroretina from blood-borne pathogens.Methods: The expression of lysozyme in human and mouse RPE cells was examined by RT-PCR or immune (cyto)histochemistry in cell cultures or retinal sections. RPE cultures were treated with different concentrations of Pam3CSK4, lipopolysaccharides (LPS), staphylococcus aureus-derived peptidoglycan (PGN-SA), Poly(I:C), and Poly(dA:dT). The mRNA expression of lysozyme was examined by qPCR and protein expression by ELISA. Poly(I:C) was injected into the subretinal space of C57BL/6J mice and eyes were collected 24 hours later and processed for the evaluation of lysozyme expression by confocal microscopy. Bactericidal activity was measured in ARPE19 cells following LYZ gene deletion using Crispr/Cas9 technology.Results: The mRNA and protein of lysozyme were detected in mouse and human RPE cells under normal conditions, although the expression levels were lower than mouse microglia BV2 or human monocytes THP-1 cells, respectively. Immunohistochemistry showed punctate lysozyme expression inside RPE cells. Lysozyme was detected by ELISA in normal RPE lysates, and in live bacteria-treated RPE supernatants. Treatment of RPE cells with Pam3CSK4, LPS, PGN-SA, and Poly(I:C) enhanced lysozyme expression. CRISPR/Cas9 deletion of lysozyme impaired bactericidal activity of ARPE19 cells and reduced their response to LPS and Poly(I:C) stimulation.Conclusions: RPE cells constitutively express antimicrobial peptide lysozyme and the expression is modulated by pathogenic challenges. RPE cells may protect the neuroretina from blood-borne pathogens by producing antimicrobial peptides, such as lysozyme.

The treatment of posterior segment disorders of the eye requires therapeutic strategies to achieve drug effects over prolonged times. Innovative colloidal delivery systems can be designed to deliver drugs to the retina and prolong their intravitreal permanence. In order to exploit pullulan (Pull) as polymeric drug carrier for intravitreal drug delivery, derivatives of hydrophobic model molecule rhodamine B (RhB) were conjugated to the pullulan backbone through linkers with different stability, namely ether (Et), hydrazone (Hy) or ester (Es) bond to obtain Pull-Et-RhB, Pull-Hy-RhB and Pull-Es-RhB, respectively. Dynamic light scattering and transmission electron microscopy analyses showed that the polymer conjugates self-assembled into 20-25 nm particles. Pull-Et-RhB was fairly stable at all tested pH values. At the vitreal pH of 7.4, 50% of RhB was released from Pull-Hy-RhB and Pull-Es-RhB in 11 and 6 days, respectively. At endosomal pH (5.5), 50% of RhB was released from Pull-Hy-RhB and Pull-Es-RhB in 4 and 1 days, respectively. Multiple particle tracking analyses in ex vivo porcine eye model showed that the diffusivity of the bioconjugates in the vitreous was about 103 times lower than in water. Flow cytometry and confocal microscopy analyses showed that bioconjugates are remarkably taken up by the retinal RPE cells. In vivo studies showed that after intravitreal injection to mice, the bioconjugates localize in the ganglion cell layer and in the inner and outer plexiform layers. Pull-Hy-RhB particles were detected also inside the retinal blood vessels. These results demonstrate that pullulan with tailored linkers for drug conjugation is a promising vehicle for long-acting intravitreal injectables that are capable to permeate to the retina.

We have found recently that nuclear uptake of the cell-impermeable DNA light-switching Ru(II)-polypyridyl cationic complexes such as [Ru(bpy)2(dppz)]Cl2 was remarkably enhanced by pentachlorophenol (PCP), by forming ion-pairing complexes via a passive diffusion mechanism. However, it is not clear whether the enhanced nuclear uptake of [Ru(bpy)2(dppz)]2+ is only limited to PCP, or it is a general phenomenon for other highly chlorinated phenols (HCPs); and if so, what are the major physicochemical factors in determining nuclear uptake? Here, we found that the nuclear uptake of [Ru(bpy)2(dppz)]2+ can also be facilitated by other two groups of HCPs including three tetrachlorophenol (TeCP) and six trichlorophenol (TCP) isomers. Interestingly and unexpectedly, 2,3,4,5-TeCP was found to be the most effective one for nuclear delivery of [Ru(bpy)2(dppz)]2+, which is even better than the most-highly chlorinated PCP, and much better than its two other TeCP isomers. Further studies showed that the nuclear uptake of [Ru(bpy)2(dppz)]2+ was positively correlated with the binding stability, but to our surprise, inversely correlated with the lipophilicity of the ion-pairing complexes formed between [Ru(bpy)2(dppz)]Cl2 and HCPs. These findings should provide new perspectives for future investigations on using ion-pairing as an effective method for delivering other bio-active metal complexes into their intended cellular targets.

Delivering potential theranostic metal complexes into preferential cellular targets is becoming of increasing interest. Here we report that nuclear uptake of a cell-impermeable DNA "light-switching" Ru(II)-polypyridyl complex can be significantly facilitated by chlorophenolate counter-anions, which was found, unexpectedly, to be correlated positively with the binding stability but inversely with the lipophilicity of the formed ion pairs.

A novel dicyanomethylene-4H-pyran based lysosome-specific near-infrared (NIR) probe, DCM-ML, is reported. It exhibits very weak fluorescence (Ф=0.007) in aqueous solution due to the energy relaxation from intramolecular rotation; but a large "off-on" NIR emission (20-folds) after specifically labeling lysosomes due to the local high viscosity instead of the local pH by both one- and two-photon excitation microscopy. Therefore, the imaging ability of DCM-ML will not confront the problems suffered by the currently used and reported pH-dependent lysosome probes (e.g., once lysosomal pH increases, their fluorescence gets quenched); The pH-independent feature of DCM-ML is further demonstrated to be a great advantage for tracing lysosomes’movements in a relatively long time, even during cellular processes when lysosomes are suffered from external stimulations that induce pH increase and apoptosis. In addition to the characteristics of pH-insensitivity and "off-on" NIR emission, DCM-ML also possesses characteristics of excellent membrane permeability, high selectivity, low cytotoxicity, good photostability and large Stokes shift (>200 nm), which qualify it as a superior wash-free NIR probe for tracking dynamic changes of lysosomes under both physiological and toxicological conditions. Hence, we believe DCM-ML may find a great potential of application in the future.

Particulate matter (PM) pollution is severe in the Beijing-Tianjin-Hebei (BTH) region. Although the air quality has improved, the average PM2.5 and PM10 concentrations in 2016 were still higher than the National Ambient Air Quality Standard by 2.0 and 1.7 times, respectively. Using the empirical orthogonal function (EOF) method to analyze the spatial characteristics of its 13 cities, it was found that the BTH region could be categorized into four districts. The first district included Xingtai, Shijiazhuang, and Baoding; the second district included Handan, Hengshui, and Langfang; the third district included Beijing, Tangshan, Cangzhou, and Tianjin; and the fourth district included Qinhuangdao, Chengde, and Zhangjiakou. PM2.5 samples were collected synchronously in five typical cities, and it was shown that the major chemical constituents of PM included organic carbon (OC), nitrate (NO3-), sulfate (SO42-), ammonium (NH4+), elemental carbon (EC), Si, Cl-, Fe, Al, and Mg. The species with the highest contents were OC in the winter, SO42- and NH4+ in the summer, and NO3- in the spring. The highest concentrations of OC, NO3-, EC, Si, Cl-, Al, and Mg were found in Baoding, and the highest concentrations of SO42-, NH4+, and Fe were found in Shijiazhuang. The sources of PM2.5 were analyzed using the positive matrix factorization model. The major sources of PM2.5 in the BTH region included coal combustion (10.9%-18.6%), secondary inorganic aerosols (35.4%-42.4%), vehicle emissions (10.6%-18.6%), soil/road dust (10.6%-23.6%), and industrial emissions (8.6%-18.2%).

Self-healing conductive composites have attracted tremendous interest in recent years due to their many important applications, especially in stretchable and reconfigurable electronics as self-healing electrodes. However, the conductivity of these conductive composite electrodes after healing is limited by the poor capability of the self-healing polymer matrix to move the conductive fillers. Herein, we report a novel stretchable self-healing conductive composite based on a polyborosiloxane (PBS)/polydimethylsiloxane (PDMS) double-network (DN) matrix. The chemically cross-linked PDMS network renders the electrode with good elasticity and mechanical robustness while the non-covalent supramolecular interactions in the PBS network provide it with self-healing and self-adhesive capabilities. Moreover, this DN matrix is able to move not only silver nanowires on the composite surfaces, but also heavier conductive fillers such as silver microflakes embedded inside the bulk due to the highly viscous flow of PBS, yielding a bulk resistivity as low as 0.002 Ω cm and achieving 100% restoration of its original conductivity after damage without any external stimulus. This unique combination of high conductivity, autonomous self-healing of both electrical conductivity and mechanical strength, and self-adhesion may endow the novel composite with a wide range of applications.

Polyhaloaromatic compounds (XAr) are ubiquitous and recalcitrant in the environment. They are potentially carcinogenic to organisms and may induce serious risks to the ecosystem, raising increasing public concern. Therefore, it is important to detect and quantify these ubiquitous XAr in the environment, and to monitor their degradation kinetics during the treatment of these recalcitrant pollutants. We have previously found that unprecedented intrinsic chemiluminescence (CL) can be produced by a haloquinones/H2O2 system, a newly-found ●OH-generating system different from the classic Fenton system. Recently, we found that the degradation of priority pollutant pentachlorophenol by the classic Fe(II)-Fenton system could produce intrinsic CL, which was mainly dependent on the generation of chloroquinone intermediates. Analogous effects were observed for all nineteen chlorophenols, other halophenols and several classes of XAr, and a novel, rapid and sensitive CL-based analytical method was developed to detect these XAr and monitor their degradation kinetics. Interestingly, for those XAr with halohydroxyl quinoid structure, a Co(II)-mediated Fenton-like system could induce a stronger CL emission and higher degradation, probably due to site-specific generation of highly-effective ●OH. These findings may have broad chemical and environmental implications for future studies, which would be helpful for developing new analytical methods and technologies to investigate those ubiquitous XAr.

Hyperaccumulators store metals in the vacuoles of leaf cells. To investigate the role of vacuolar compartmentalization in Cd accumulation, chelation and induced antioxidation, we quantified the amounts of total cadmium (Cd), Cd2+, glutathione (GSH) and reactive oxygen species (ROS) in leaf cells of Solanum nigrum L. The results confirmed that vacuoles were, indeed, the main storage compartments for Cd. We then found that with increased Cd treatment concentration, the proportion of vacuolar Cd in protoplasts showed its ultimate storage capacity (82.24 %-83.40 %), and the Cd concentration stored in the protoplast maintained at a certain level (73.81-77.46 mg L-1). Besides, studies on different forms of Cd showed that the chelation state was dominant in the protoplast. The large level appearance of Cd2+ outside the vacuole revealed the limitations of vacuolar Cd2+ sequestration. The relationships between the combined forms of Cd and GSH outside the vacuole (R2 = 0.9906) showed GSH was mainly distributed to important compartments for chelation, not to vacuoles. We also demonstrated the presence of ROS-induced oxidative stress and detoxification mediated by the antioxidant GSH in vacuoles, suggesting that sequestration into vacuoles is an active process accompanied by chelation and antioxidant-mediated detoxification.

Developing the cell-impermeable Ru(II) polypyridyl cationic complexes as effective photosensitizers (PS) which have high cellular uptake and photo-toxicity, but low dark toxicity, is quite challenging. Here we found that the highly reactive singlet oxygen (1O2) can be generated by the irradiation of a typical Ru(II) polypyridyl complex Ru(II)tris(tetramethylphenanthroline) ([Ru(TMP)3]2+) under visible light irradiation by ESR with TEMPO (2,2,6,6-tetramethyl-4-piperidone-N-oxyl) as 1O2 probe. Effective cellular and nuclear delivery of cationic [Ru(TMP)3]2+ was achieved through our recently developed ion-pairing method, and 2,3,4,5-tetrachlorophenol (2,3,4,5-TeCP) was found to be the most effective among all chlorophenols tested. The accelerated cellular, especially nuclear uptake of [Ru(TMP)3]2+ results in the formation of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) and DNA strand breaks, caspase 3/7 activation and cell apoptosis in HeLa cells upon light irradiation. More importantly, compared with other traditional photosensitizers, [Ru(TMP)3]2+ showed significant photo-toxicity but low dark toxicity. Similar effects were observed when 2,3,4,5-TeCP was substituted by the currently clinically used anti-inflammatory drug flufenamic acid. This represents the first report that the cell-impermeable Ru(II) polypyridyl complex ion-paired with suitable lipophilic counter-anions functions as potent intracellular photosensitizer under visible light irradiation mainly via a 1O2-mediated mechanism. These findings should provide new perspectives for future investigations on other metal complexes with similar characteristics as promising photosensitizers for potential photodynamic therapy.

An in-depth understanding of the mechanisms of cellular uptake and efflux would facilitate the design of metal complexes with not only better functionality and targeted theranostic efficiency, but also with controlled toxicity. Here we find, unexpectedly, that the DNA "light-switching" Ru(ii)-polypyridyl complex [Ru(phen)2(dppz)]2+ already delivered to the nucleus via ion-pairing with chlorophenolate counter-anions can gradually efflux to the cytoplasm when the cells were washed and incubated with fresh culture-medium. Interestingly, [Ru(phen)2(dppz)]2+ effluxed to the cytoplasm can be redirected back to the nucleus when the chlorophenolate counter-anions were added again. The efflux of nuclear [Ru(phen)2(dppz)]2+ was found to be mediated mainly via ATP-binding cassette (ABC) transporter proteins. Analogous reversible, but enantio-selective nuclear uptake and efflux were observed with the two pure chiral forms of [Ru(phen)2(dppz)]Cl2. This represents the first report of reversible and controllable nuclear uptake and efflux of a DNA "light-switching" Ru(ii)-complex in living-cells via ion-pairing, which should provide novel insights for future research on using ion-pairing as an effective approach to control the cellular uptake and redistribution of other potential theranostic metal complexes.

Many immune responses depend upon activation of NF-κB, a key transcription factor in the elicitation of a cytokine response. Here we demonstrate that N4BP1 inhibited TLR-dependent activation of NF-κB by interacting with the NF-κB signaling essential modulator (NEMO, also known as IκB kinase γ) to attenuate NEMO-NEMO dimerization or oligomerization. The UBA-like (ubiquitin associated-like) and CUE-like (ubiquitin conjugation to ER degradation) domains in N4BP1 mediated the interaction with the NEMO COZI domain. Both in vitro and in mice, N4bp1 deficiency specifically enhanced TRIF-independent (TLR2, TLR7, or TLR9-mediated), but not TRIF-dependent (TLR3 or TLR4-mediated), NF-κB activation leading to increased production of proinflammatory cytokines. In response to TLR4 or TLR3 activation, TRIF caused activation of caspase 8, which cleaved N4BP1 distal to residues D424 and D490 and abolished its inhibitory effect. N4bp1-/- mice also exhibited diminished numbers of T cells in the peripheral blood. Our work identifies N4BP1 as an inhibitory checkpoint protein that must be overcome to activate NF-κB, and a TRIF-initiated caspase 8-dependent mechanism by which this is accomplished.

Endowing materials with self-healing ability is an effective way to enhance the reliability, durability and functionality of flexible electronic devices. Recently, self-healing materials have made great progress in improving self-healing efficiency. However, there’re still problems to solve, such as harsh self-healing conditions and great mechanical loss, and the broken conductive network that cannot follow the dynamic reconstruction of the self-healing polymer. Here we report a onepot method of using the boric acid to modify hydroxyl terminated polydimethylsiloxane to prepare polyborosiloxanes (PBS) with supramolecular network matrix, and at the same time we introduce the silicone (PDMS) covalent network in supramolecular network matrix to form double network structure. The PBS network with dative bond, hydrogen bond, topological entanglement can provide self-healing and selfadhesion capability, while the chemically cross-linked PDMS network acts as a skeleton in the matrix and renders elasticity and mechanical robustness. Mechanical and electrical characterization methods are applied to investigate the selfhealing behavior of PBS composite. More importantly, when a nanowire conductive network is surrounded by the polymer matrix, the broken conductive network can follow the dynamic reconstruction of the self-healing polymer and autonomously heal to recover not only its high conductivity (100%) but also its mechanical properties (88%). This one-pot method for preparation of autonomous self-healable and stretchable electrode will provide new ideas for flexible pressure sensor design, and promote its application in various areas, such as electronic skin, health monitoring and human-machine interaction.

Retinal disease and loss of vision can result from any disruption of the complex pathways controlling retinal development and homeostasis. Forward genetics provides an excellent tool to find, in an unbiased manner, genes that are essential to these processes. Using N -ethyl- N -nitrosourea mutagenesis in mice in combination with a screening protocol using optical coherence tomography (OCT) and automated meiotic mapping, we identified 11 mutations presumably causative of retinal phenotypes in genes previously known to be essential for retinal integrity. In addition, we found multiple statistically significant gene-phenotype associations that have not been reported previously and decided to target one of these genes, Sfxn3 (encoding sideroflexin-3), using CRISPR/Cas9 technology. We demonstrate, using OCT, light microscopy, and electroretinography, that two Sfxn3 −/− mouse lines developed progressive and severe outer retinal degeneration. Electron microscopy showed thinning of the retinal pigment epithelium and disruption of the external limiting membrane. Using single-cell RNA sequencing of retinal cells isolated from C57BL/6J mice, we demonstrate that Sfxn3 is expressed in several bipolar cell subtypes, retinal ganglion cells, and some amacrine cell subtypes but not significantly in Müller cells or photoreceptors. In situ hybridization confirmed these findings. Furthermore, pathway analysis suggests that Sfxn3 may be associated with synaptic homeostasis. Importantly, electron microscopy analysis showed disruption of synapses and synaptic ribbons in the outer plexiform layer of Sfxn3 −/− mice. Our work describes a previously unknown requirement for Sfxn3 in retinal function.

The small GTPase RABL3 is an oncogene of unknown physiological function. Homozygous knockout alleles of mouse Rabl3 were embryonic lethal, but a viable hypomorphic allele ( xiamen [ xm ]) causing in-frame deletion of four amino acids from the interswitch region resulted in profound defects in lymphopoiesis. Impaired lymphoid progenitor development led to deficiencies of B cells, T cells, and natural killer (NK) cells in Rabl3 xm/xm mice. T cells and NK cells exhibited impaired cytolytic activity, and mice infected with mouse cytomegalovirus (MCMV) displayed elevated titers in the spleen. Myeloid cells were normal in number and function. Biophysical and crystallographic studies demonstrated that RABL3 formed a homodimer in solution via interactions between the effector binding surfaces on each subunit; monomers adopted a typical small G protein fold. RABL3 xm displayed a large compensatory alteration in switch I, which adopted a β-strand configuration normally provided by the deleted interswitch residues, thereby permitting homodimer formation. Dysregulated effector binding due to conformational changes in the switch I–interswitch–switch II module likely underlies the xm phenotype. One such effector may be GPR89, putatively an ion channel or G protein-coupled receptor (GPCR). RABL3, but not RABL3 xm , strongly associated with and stabilized GPR89, and an N -ethyl- N -nitrosourea (ENU)-induced mutation ( explorer ) in Gpr89 phenocopied Rabl3 xm .

Nitrate (NO3−), sulfate (SO42−) and ammonium (NH4+) in airborne fine particles (PM2.5) play a vital role in the formation of heavy air pollution in northern China. In particular, the increasing contribution of NO3− to PM2.5 has attracted worldwide attention. In this study, a highly time-resolved analyzer was used to measure water-soluble inorganic ions in PM2.5 in one of the fastest-developing megacities, Tianjin, China, from November 15 to March 15 (wintertime heating period) in 2014–2019. Severe PM2.5 pollution episodes markedly decreased during the heating period from 2014 to 2019. The highest concentrations of NO3− and SO42− were recorded in the heating period of 2015/2016. Afterwards, NO3− decreased from 2015/2016 (20.2 ± 23.8 μg/m3) to 2017/2018 (11.6 ± 14.8 μg/m3) but increased with increasing NOx concentrations during the heating period of 2018/2019. A continuous decrease in the SO2 concentration led to a decrease in SO42− from 2015/2016 (16.8 ± 21.8 μg/m3) to 2018/2019 (6.5 ± 8.9 μg/m3). The NO3− and SO42− concentrations increased as the air quality deteriorated. However, the proportion of NO3− and SO42− in PM2.5 slightly increased when the air quality deteriorated from moderate pollution (MP) to severe pollution (SP) levels. The average molar ratios of NH4+ to [NO3−+2 × (SO42−)] were 1.7, 0.9, 1.2, 1.2 and 1.5 for the heating periods of 2014/2015, 2015/2016, 2016/2017, 2017/2018 and 2018/2019, respectively, most of which were higher than 1.0, thus revealing an overall excess of NH4+ during the heating periods. However, the molar equivalent ratios of [NH4+] to [NO3−+2 × (SO42−)] were less than 1 under increasing PM2.5 pollution. The molar equivalent ratios of [NO3−]/[SO42−] were positively correlated with those of [NH4+]/[SO42−]. When the molar equivalent ratios of [NH4+]/[SO42−] were more than 1.5, those of [NO3−]/[SO42−] increased from close to 1 to higher values, indicating that the dominance of NO3− formation played an important role. The results of nonparametric wind regression exhibited distinct hot spots of NO3−, SO42− and NH4+ (higher concentrations) in the wind sectors between NE and SE at wind speeds of approximately 6–21 km/h. The southern areas in the North China Plain and parts of the western areas of China contributed more NO3−, SO42− and NH4+ than other areas to the study site. The abovementioned areas were also characterized by a higher contribution of NO3− than of SO42− to the study site and by NH4+-rich conditions. In summary, more efforts should be made to reduce NOx in the Beijing-Tianjin-Hebei region. This study provides observational evidence of the increasingly important role of nitrate as well as scientific support for formulating effective control strategies for regional haze in China.

At the mesoscopic level of commercial lithium ion battery (LIB), it is widely believed that the poor contacts between current collector (CC) and electrode materials (EM) lead to weak adhesions and large interfacial electric resistances. However, systematic quantitative analyses of the influence of the interfacial properties of CC are still scarce. Here, we built a model interface between CC and electrode materials by directly growing hierarchical graphene films on commercial Al foil CC, and we performed systematic quantitative studies of the interfacial properties therein. Our results show that the interfacial electric resistance dominates, i.e. ∼2 orders of magnitude higher than that of electrode materials. The interfacial resistance could be eliminated by hierarchical graphene interlayer. Cathode on CC with eliminated interfacial resistance could deliver much improved power density outputs. Our work quantifies the mesoscopic factors influencing the battery performance and offers practical guidelines of boosting the performance of LIBs and beyond.

The high-resolution technique transmission electron microscopy (TEM), with OsO4 as the traditional fixative, is an essential tool for cell biology and medicine. Although OsO4 has been extensively used, it is far from perfect because of its high volatility and toxicity. Os(II) polypyridyl complexes like [Os(phen)2(dppz)]2+ (phen = 1,10-phenanthroline; dppz = dipyridophenazine) are not only the well-known molecular DNA “light-switches” but also the potential ideal candidates for TEM studies. Here, we report that the cell-impermeable cationic [Os(phen)2(dppz)]2+ can be preferentially delivered into the live-cell nucleus through ion-pairing with chlorophenolate counter-anions, where it functions as an unparalleled enantioselective nuclear DNA imaging reagent especially suitable for correlative light and electron microscopy (CLEM) studies in both living and fixed cells, which can clearly visualize chromosome aggregation and decondensation during mitosis simultaneously. We propose that the chiral Os(II) polypyr...

Polymeric solid-solid phase change materials (PSSPCMs) can essentially solve the leakage problem of physically composited solid-solid phase change materials, but the phase change enthalpies, which are usually far lower than the theoretical values, limit their applications. In this work, three PSSPCMs were prepared by co-esterification and polymerization with different amount of stearic acid (SA). The PSSPCMs suffered from lower crystallinities and activation energies at transition than pure SA, indicating that confinement of polymeric network on crystalline domains may lead to the decrease of enthalpy. According to analysis from generalized two-dimensional correlation Fourier transform infrared, the polymer network confinement in PSSPCMs mainly restricted the vibrations of νasCH3, νCH, and νsCH3. In-depth understanding of the interaction between the crystalline chains and the polymeric networks would be beneficial for molecule design of novel PSSPCMs with high enthalpy.

Bisphenol A polycarbonate (PC) is difficult to crystallize. In this study, it was found that PC could rapidly accomplish melt crystallization only within 8 min by laying poly(ethylene glycol) (PEG) film on it. Polarized optical microscope (POM) was applied to trace the growth of spherulites of PC in PEG/PC double-layer films during isothermal crystallization in a wide range of temperatures, which were above the melting temperature for PEG. The dependence of spherulitic growth rate (G) on isothermal crystallization temperature (Tc) followed a “bell-shape” curve, just like some other semicrystalline polymers did. A PEG film was laid on a PC film at 250 °C for 5 min to obtain a PEG/PC double-layer film, which was subsequently quenched to different Tc’s for observation on its crystallization process by using POM. It was surprising to observe that the spherulitic growth rate of PC was significantly improved and the crystallization time was obviously shortened. The miscibility for PEG/PC blends was evaluated by...

The compensatory proliferation of insulin-producing β cells is critical to maintaining glucose homeostasis at the early stage of type 2 diabetes. Failure of β cells to proliferate results in hyperglycemia and insulin dependence in patients. To understand the effect of the interplay between β cell compensation and lipid metabolism upon obesity and peripheral insulin resistance, we eliminated LDL receptor–related protein 1 (LRP1), a pleiotropic mediator of cholesterol, insulin, energy metabolism, and other cellular processes, in β cells. Upon high-fat diet exposure, LRP1 ablation significantly impaired insulin secretion and proliferation of β cells. The diminished insulin signaling was partly contributed to by the hypersensitivity to glucose-induced, Ca2+-dependent activation of Erk and the mTORC1 effector p85 S6K1. Surprisingly, in LRP1-deficient islets, lipotoxic sphingolipids were mitigated by improved lipid metabolism, mediated at least in part by the master transcriptional regulator PPARγ2. Acute overexpression of PPARγ2 in β cells impaired insulin signaling and insulin secretion. Elimination of Apbb2, a functional regulator of LRP1 cytoplasmic domain, also impaired β cell function in a similar fashion. In summary, our results uncover the double-edged effects of intracellular lipid metabolism on β cell function and viability in obesity and type 2 diabetes and highlight LRP1 as an essential regulator of these processes.

Two-dimensional (2D) polymer has attracted considerable attention due to its excellent properties. Although a number of 2D polymers have been reported, preparation of free-standing single-layer 2D polymers in solution is still a big challenge. Here we report a facile and highly efficient strategy for synthesis of free-standing single-layer covalent pseudo-2D polymers via free radical polymerization in water on a large scale. The strategy designated as “two-dimensional self-assembly polymerization (2DSP)” includes formation of supramolecular 2D nanosheets by self-assembly of bola-amphiphilic monomer that bearing two maleic acid moieties and transformation of supramolecular 2D nanosheets to covalent pseudo-2D polymers by copolymerization with vinyl monomers. We find that the counterion of the bola-amphiphile has a significant influence on formation of single-layer supramolecular 2D nanosheets, and the formation of 2D polymer sheets is highly related to the vinyl monomers. The unique 2D polymer sheets were u...

Tb3+-doped and Eu2+, Tb3+ co-doped Ca9Y(PO4)7 phosphors were synthesized by conventional solid-state method. Additionally, the luminescence properties, decay behavior and energy transfer mechanism have already been investigated in detail. The green emission intensity of Tb3+ ions under NUV excitation is weak due to its spin-forbidden f-f transition. While Eu2+ can efficiently absorb NUV light and yield broad blue emission, most of which can be absorbed by Tb3+ ions. Thus, the emission color can be easily tuned from cyan to green through the energy transfer of Eu2+→Tb3+ in Ca9Y(PO4)7:Eu2+,Tb3+ phosphor. In this work, the phenomenon of cross-relaxation between 5D3 and 5D4 are also mentioned. The energy transfer is confirmed to be resulted from a quadrupole-quadrupole mechanism.

A range of Ca 10.5-1.5 x La x (PO 4 ) 7 :Eu 2+ phosphors were synthesized by high temperature solid state method. Subsequently we studied the crystal structures and luminescent properties through X-ray diffraction, photoluminescence and photoluminescence excitation, diffuse reflection spectra, Raman spectra and decay curves systematically. Based on the special crystal structure of β -Ca 3 (PO 4 ) 2 :Eu 2+ , its emission undergoes a variation from violet–blue to cyan through introducing La 3+ . The substitution of La 3+ for Ca 2+ could form some cation vacancies in Ca(4) sites according to the scheme 3Ca 2+ = 2La 3+ + □ due to the different ion valence, which compels Eu 2+ to migrate from Ca(4) site to other sites. Additionally, the formation of the cation vacancies can further reduce the thermal stability of phosphors.

T follicular helper cells (TFH) participate in germinal center (GC) development and are necessary for B cell production of high-affinity, isotype-switched antibodies. In a forward genetic screen, we identified a missense mutation in Prkd2, encoding the serine/threonine kinase protein kinase D2, which caused elevated titers of immunoglobulin E (IgE) in the serum. Subsequent analysis of serum antibodies in mice with a targeted null mutation of Prkd2 demonstrated polyclonal hypergammaglobulinemia of IgE, IgG1, and IgA isotypes, which was exacerbated by the T cell-dependent humoral response to immunization. GC formation and GC B cells were increased in Prkd2-/- spleens. These effects were the result of excessive cell-autonomous TFH development caused by unrestricted Bcl6 nuclear translocation in Prkd2-/- CD4+ T cells. Prkd2 directly binds to Bcl6, and Prkd2-dependent phosphorylation of Bcl6 is necessary to constrain Bcl6 to the cytoplasm, thereby limiting TFH development. In response to immunization, Bcl6 repressed Prkd2 expression in CD4+ T cells, thereby committing them to TFH development. Thus, Prkd2 and Bcl6 form a mutually inhibitory positive feedback loop that controls the stable transition from naive CD4+ T cells to TFH during the adaptive immune response.

This is the first study on the deployment of direct current atmospheric pressure microplasma technique for the single step synthesis of gold nanoparticle/graphene oxide (AuNP/GO) nanocomposites. The nanocomposites were characterized using ultraviolet–visible spectroscopy (UV–vis), x-ray diffraction and x-ray photoelectron spectroscopy and their formation mechanisms have been discussed in detail. Our AuNP/GO nanocomposites are highly biocompatible and have demonstrated surface enhanced Raman scattering (SERS) properties as compared to pure AuNPs and pure GO. Their potential as SERS substrate has been further demonstrated using probe molecules (methylene blue) at different concentrations.

The rapid development of additive manufacturing techniques, also known as three-dimensional (3D) printing, is driving innovations in polymer chemistry, materials science, and engineering. Among current 3D printing techniques, direct ink writing (DIW) employs viscoelastic materials as inks, which are capable of constructing sophisticated 3D architectures at ambient conditions. In this perspective, polymer designs that meet the rheological requirements for direct ink writing are outlined and successful examples are summarized, which include the development of polymer micelles, co-assembled hydrogels, supramolecularly cross-linked systems, polymer liquids with microcrystalline domains, and hydrogels with dynamic covalent cross-links. Furthermore, advanced polymer designs that reinforce the mechanical properties of these 3D printing materials, as well as the integration of functional moieties to these materials are discussed to inspire new polymer designs for direct ink writing and broadly 3D printing.

Bottlebrush polymers (BBPs) have emerged as intriguing class of materials for an array of applications, including supersoft elastomers, organic optoelectronics, templates for crafting one-dimensional (1D) nanomaterials, energy storage, and biomedical devices. The densely-grafted side chains along the linear backbones afford BBPs with extended cylindrical shapes and the absence of entanglements. The architectures of BBPs can be readily tuned by manipulating the chemical structures and compositions, both of which govern the viscoelastic properties, melt processability, and alignment of BBPs. This enables the crafting of BBPs with controlled dimensions, compositions, and architectures by capitalizing on advanced synthetic techniques. However, challenges remain in the synthesis and applications of BBPs with precisely controlled architectures. This review aims to provide a comprehensive and critical summary that highlights the recent advances in BBPs in terms of their controlled syntheses, self-assembly, properties, and applications. In addition, challenges facing the syntheses and applications of BBPs will be underscored, with the corresponding solutions to these issues for improving the control over chemical structures (e.g., introducing conjugated side chains), compositions (e.g., other than the widely used polynorbornene or polyacrylate backbone), and utilities (e.g., as solid-state electrolyte in energy storage devices) of BBPs.

Diblock copolymers of poly(tert-butyl acrylate)-b-poly(azidomethyl styrene) were synthesized and used to modify multiwalled carbon nanotubes. After hydrolysis of the PtBA block, hydrophilic MWCNTs with poly(acrylic acid) brushes (MWCNT-PAA) were obtained and characterized. Then novel polyacrylamide composite hydrogels were prepared by in situ polymerization of acrylamide in presence of MWCNT-PAA. Our results show that the mechanical properties of the composite hydrogels are significantly improved with increasing the content of MWCNT-PAA. For the composite hydrogels, when the content of MWCNTs (weight ratio of MWCNT-PAA/AM) reached to 1.4 wt%, the tensile strength and the elongation were measured to be 82.7 kPa and 508% respectively, which are at least 3.9 and 3.1 times higher than those of the polyacrylamide hydrogel. Moreover, the swelling property of the hydrogel can be regulated through the content of MWCNT-PAA. Therefore, these hydrogels may have potential applications in biomedical fields without the limitations of water capacity and mechanical properties.

In this study a series of long chain branched polycarbonates (LCB-PCs) was prepared from linear PC precursors through gamma radiation with addition of a difunctional monomer, divinyl benzene (DVB) of varying amounts. The topological structures of the linear PCs and LCB-PCs were measured by size-exclusion chromatography coupled with a multiangle light scattering detector (SEC-MALLS) and rheology. SEC-MALLS measurements showed that the topological structures of the PCs were changed with the introduction of LCB structures. Rheological measurements showed that the LCB structures of the LCB-PCs contributed to enhancements of storage modulus, complex viscosity, shear-thinning behavior, and the deviation of phase angle, δ, from the “standard” curve of linear PCs in the δ − |G*| plots (van Gurp–Palmen plot). Modulated differential scanning calorimetry (MDSC) measurements showed that the glass transition temperature, Tg, of LCB-PCs decreases with increasing LCB degree, which is attributed to the combined effects of both increased branching density and free chain ends. LCB structures introduced into PCs did not apparently weaken the tensile properties of the PC materials, whereas the notched Izod impact strength could be obviously improved by the LCB structures. More importantly, the influence of LCB structures on the environmental stress cracking (ESC) behavior of LCB-PCs was explored and the results indicated that the ESC properties of LCB-PCs could be significantly enhanced with the introduction of LCB structures, which makes the application of LCB-PCs as the window view materials for helmets worn by astronauts while in outer space a possibility.

Purpose To develop a model that can recapitulate key features of macular fibrosis in neovascular age-related macular degeneration (nAMD). Methods Adult C57BL/6J mice received three laser burns/eye to induce choroidal neovascularization (CNV). Seven days later, a second laser burn was directed to each of the neovascular lesions. Traditional laser-induced CNV was used as a control. Lesions were monitored at 10, 20, 30, and 40 days post-laser (p.l) treatment by fundus imaging, fundus fluorescein angiography, optical coherence tomography (OCT), and immunohistochemistry. The expression of collagen-1 (COL-1), fibronectin, α-smooth muscle actin, F4/80, complement factor B (CFB), Complement component 3 (C3), transforming growth factor-β (TGF-β), and fibroblast growth factor 2 (FGF2) in retina and retinal pigment epithelium/choroid was examined by immunofluorescence and reverse transcription polymerase chain reaction. Results The two-stage laser protocol induced significantly larger lesions than the traditional laser-CNV by OCT and immunohistochemistry at all time points. Confocal microscopy detected COL-1+ fibers and IBA1+/CD31+ blood vessels in lesions from the two-stage laser protocol 30 to 40 days p.l. Lesions from traditional laser-CNV contain only COL-1+ fibers but not blood vessels at this time point. Higher levels of proinflammatory (inducible nitric oxide synthase (iNOS), C3, CFB) and profibrotic (TGF-β, FGF2, and vascular endothelial growth factor) genes were detected in the retinas from the two-stage laser-induced lesions compared with the traditional laser-CNV lesion. Higher number of infiltrating F4/80 macrophages was also observed in and around the two-stage laser-induced fibrotic lesion. Conclusions The two-stage laser treatment induced subretinal fibrovascular membranes that persist over 40 days. Translational relevance The model is a useful tool to study the mechanism of macular fibrosis in nAMD and test antifibrotic drugs.