Plasma MERTK is a promising biomarker for the diagnosis and prognosis of HBV-related acute-on-chronic liver failure.

BACKGROUND: Hepatitis B-related acute-on-chronic liver failure (HBV-ACLF) has a high short-term mortality. This study aimed to determine the diagnostic and prognostic role of MER tyrosine kinase (MERTK) in HBV-ACLF patients. METHODS: Transcriptomics analysis evaluated MERTK expression and function during disease progression. The diagnostic and prognostic significance of MERTK for HBV-ACLF patients were verified by ELISA, the area under the receiver operating characteristic curve (AUROC) analysis, and immunohistochemistry (IHC) of liver tissues. RESULTS: MERTK mRNA was highly expressed in the HBV-ACLF compared to the liver cirrhosis (LC), chronic hepatitis B (CHB) and normal controls (NC) groups. Elevated MERTK mRNA predicted poor prognosis for HBV-ACLF at 28/90 days (AUROCs=0.814/0.731). Functional analysis showed MERTK was significantly associated with TLR and inflammatory signaling, and several key biological processes. External validation with 285 plasma subjects confirmed the high diagnostic accuracy of plasma MERTK for HBV-ACLF (AUROC=0.859) and potential prognostic value for 28/90-day mortality rates (AUROC=0.673 and 0.644, respectively). Risk stratification analysis indicated higher mortality risk for patients with plasma MERTK level above the cut-off value. Moreover, IHC staining showed increasing MERTK expression from NC, CHB and LC to HBV-ACLF patients. CONCLUSIONS: MERTK shows promise as a candidate biomarker for early diagnosis and prognosis of HBV-ACLF.

Thrombospondin 1 enhances systemic inflammation and disease severity in acute-on-chronic liver failure.

BACKGROUND: The key role of thrombospondin 1 (THBS1) in the pathogenesis of acute-on-chronic liver failure (ACLF) is unclear. Here, we present a transcriptome approach to evaluate THBS1 as a potential biomarker in ACLF disease pathogenesis. METHODS: Biobanked peripheral blood mononuclear cells (PBMCs) from 330 subjects with hepatitis B virus (HBV)-related etiologies, including HBV-ACLF, liver cirrhosis (LC), and chronic hepatitis B (CHB), and normal controls (NC) randomly selected from the Chinese Group on the Study of Severe Hepatitis B (COSSH) prospective multicenter cohort underwent transcriptome analyses (ACLF = 20; LC = 10; CHB = 10; NC = 15); the findings were externally validated in participants from COSSH cohort, an ACLF rat model and hepatocyte-specific THBS1 knockout mice. RESULTS: THBS1 was the top significantly differentially expressed gene in the PBMC transcriptome, with the most significant upregulation in ACLF, and quantitative polymerase chain reaction (ACLF = 110; LC = 60; CHB = 60; NC = 45) was used to verify that THBS1 expression corresponded to ACLF disease severity outcome, including inflammation and hepatocellular apoptosis. THBS1 showed good predictive ability for ACLF short-term mortality, with an area under the receiver operating characteristic curve (AUROC) of 0.8438 and 0.7778 at 28 and 90 days, respectively. Enzyme-linked immunosorbent assay validation of the plasma THBS1 using an expanded COSSH cohort subjects (ACLF = 198; LC = 50; CHB = 50; NC = 50) showed significant correlation between THBS1 with ALT and γ-GT (P = 0.01), and offered a similarly good prognostication predictive ability (AUROC = 0.7445 and 0.7175) at 28 and 90 days, respectively. ACLF patients with high-risk short-term mortality were identified based on plasma THBS1 optimal cut-off value (< 28 µg/ml). External validation in ACLF rat serum and livers confirmed the functional association between THBS1, the immune response and hepatocellular apoptosis. Hepatocyte-specific THBS1 knockout improved mouse survival, significantly repressed major inflammatory cytokines, enhanced the expression of several anti-inflammatory mediators and impeded hepatocellular apoptosis. CONCLUSIONS: THBS1 might be an ACLF disease development-related biomarker, promoting inflammatory responses and hepatocellular apoptosis, that could provide clinicians with a new molecular target for improving diagnostic and therapeutic strategies.

Photoswitching in a Liquid Crystalline Pt(II) Coordination Complex.

Photoswitching of photoluminescence has sparked tremendous research interests for super-resolution imaging, high-security-level anti-counterfeiting, and other high-tech applications. However, the excitation of photoluminescence is usually ready to trigger the photoswitching process, making the photoluminescence readout unreliable. Herein, we report a new photoswitch by the marriage of spiropyran with platinum(II) coordination complex. Viable photoluminescence can be achieved upon excitation by 480 nm visible light while the photoswitching can be easily triggered by 365 nm UV light. The feasible photoswitching may be benefited from the formed liquid crystalline (LC) phase of the designed photoswitch as a crystalline spiropyran is normally unable to implement photoswitching. Compared to the counterparts, this LC photoswitch can show distinct and reliable apparent colors and emission colors before and after photoswitching, which may promise the utility in high-security-level anti-counterfeiting and other advanced information technologies.

Predicting the Onset of Hepatitis B Virus-Related Acute-on-Chronic Liver Failure.

BACKGROUND & AIMS: Acute-on-chronic liver failure (ACLF) is a life-threatening syndrome with rapid progression. This study aimed to develop and validate a prognostic score to predict the onset of ACLF in hepatitis B virus (HBV) etiology. METHODS: The prospective clinical data of 1373 patients with acute deterioration of HBV-related chronic liver disease were used to identify clinical characteristics and develop a prognostic score for the onset of ACLF. RESULTS: Of the patients assessed using the Chinese Group on the Study of Severe Hepatitis B (COSSH)-ACLF criteria, 903 patients with non-ACLF at admission (1 received transplantation at 5 days) were stratified: 71 with progression to ACLF and 831 without progression to ACLF at 7 days. Four predictors (total bilirubin, international normalized ratio, alanine aminotransferase, and ferritin) were associated significantly with ACLF onset at 7 days. The COSSH-onset-ACLF score was constituted as follows: (0.101 × ln [alanine aminotransferase] + 0.819 × ln [total bilirubin] + 2.820 × ln [international normalized ratio] + 0.016 × ln [ferritin]). The C-indexes of the new score for 7-/14-/28-day onset (0.928/0.925/0.913) were significantly higher than those of 5 other scores (Chronic Liver Failure Consortium ACLF development score/Model for End-stage Liver Disease score/Model for End-stage Liver Disease sodium score/COSSH-ACLF score/Chronic liver failure Consortium ACLF score; all P < .001). The improvement in predictive errors, time-dependent receiver operating characteristic, probability density function evaluation, and calibration curves of the new score showed the highest predictive value for ACLF onset at 7/14/28 days. Risk stratification of the new score showed 2 strata with high and low risk (≥6.3/<6.3) of ACLF onset. The external validation group further confirmed the earlier results. CONCLUSIONS: A new prognostic score based on 4 predictors can accurately predict the 7-/14-/28-day onset of ACLF in patients with acute deterioration of HBV-related chronic liver disease and might be used to guide clinical management.

The bromoporphyrins as promising anti-tumor photosensitizers in vitro.

The synthesis of ideal photosensitizers (PSs) is considered to be the most significant bottleneck in photodynamic therapy (PDT). To discover novel PSs with excellent photodynamic anti-tumor activities, a series of novel photosensitizers 5,15-diaryl-10,20-dibromoporphyrins (I1-6) were synthesized by a facile method. Compared with hematoporphyrin monomethyl ether (HMME) as the representative porphyrin-based photosensitizers, it is found that not only the longest absorption wavelength of all compounds was red-shifted to therapeutic window (660 nm) of photodynamic therapy, but also the singlet oxygen quantum yields were significantly increased. Furthermore, all compounds exhibited lower dark toxicity (except I2) and stronger phototoxicity (except I4) against Eca-109 tumor cells than HMME. Among them, I3 possessed the highest singlet oxygen quantum yield (ΦΔ = 0.205), the lower dark toxicity and the strongest phototoxicity (IC50 = 3.5 µM) in vitro. The findings indicated the compounds I3 had the potential to become anti-tumor agents for PDT.

PBMC transcriptomics identifies immune-metabolism disorder during the development of HBV-ACLF.

OBJECTIVE: Hepatitis B virus-related acute-on-chronic liver failure (HBV-ACLF) pathophysiology remains unclear. This study aims to characterise the molecular basis of HBV-ACLF using transcriptomics. METHODS: Four hundred subjects with HBV-ACLF, acute-on-chronic hepatic dysfunction (ACHD), liver cirrhosis (LC) or chronic hepatitis B (CHB) and normal controls (NC) from a prospective multicentre cohort were studied, and 65 subjects (ACLF, 20; ACHD, 10; LC, 10; CHB, 10; NC, 15) among them underwent mRNA sequencing using peripheral blood mononuclear cells (PBMCs). RESULTS: The functional synergy analysis focusing on seven bioprocesses related to the PBMC response and the top 500 differentially expressed genes (DEGs) showed that viral processes were associated with all disease stages. Immune dysregulation, as the most prominent change and disorder triggered by HBV exacerbation, drove CHB or LC to ACHD and ACLF. Metabolic disruption was significant in ACHD and severe in ACLF. The analysis of 62 overlapping DEGs further linked the HBV-based immune-metabolism disorder to ACLF progression. The signatures of interferon-related, neutrophil-related and monocyte-related pathways related to the innate immune response were significantly upregulated. Signatures linked to the adaptive immune response were downregulated. Disruptions of lipid and fatty acid metabolism were observed during ACLF development. External validation of four DEGs underlying the aforementioned molecular mechanism in patients and experimental rats confirmed their specificity and potential as biomarkers for HBV-ACLF pathogenesis. CONCLUSIONS: This study highlights immune-metabolism disorder triggered by HBV exacerbation as a potential mechanism of HBV-ACLF and may indicate a novel diagnostic and treatment target to reduce HBV-ACLF-related mortality.

A Porphyrinic Donor-Acceptor Conjugated Porous Polymer as Highly Efficient Photocatalyst for PET-RAFT Polymerization.

Heterogeneous catalysts offer a highly desirable platform for exploring environmental-benign transformation systems, yet, they typically suffer from significant loss of catalytic efficiency compared with their homogeneous counterparts. Here, the facile synthesis of a porphyrinic conjugated porous polymer incorporated with imidazolium bromide moieties by taking advantage of the Debus-Radziszewski reaction is reported. Owing to the unique donor-acceptor structure, this heterogeneous and metal-free photocatalyst exhibits much improved catalytic activity compared with its small molecular analogs in photoinduced electron transfer reversible addition-fragmentation chain transfer (PET-RAFT) polymerization, producing polymers with narrow distribution (D = 1.06-1.18) and high degree of chain-end fidelity. Moreover, the heterogeneous catalyst can be easily separated at the end of polymerization by centrifugation and recycled for five independent PET-RAFT polymerizations without obvious decreases in catalytic efficiency.

Photopatterning of Carbon Dots in Poly(vinyl alcohol) with Photoacid Generators.

Carbon dots (CDs) have drawn considerable attention owing to their attractive photoluminescence, advantageous chemical tolerance, good biocompatibility, and so on. However, it remains challenging to tune their photoluminescence spatially and temporally due to their high photostability. Herein, a viable approach to in-situ dialing the photoluminescence of CDs by using light in the presence of a photoacid generator (PAG, e.g., diphenyliodonium hexafluorophosphate) is demonstrated. Fluorescence quenching occurs upon light irradiation due to the protonation of pyridine and amino nitrogen atoms of CDs according to X-ray photoelectron spectroscopy and cyclic voltammetry. As such, blue, green, and red color fluorescent patterns of CDs are ready to form in poly(vinyl alcohol) by light irradiation under photomask. These patterns not only show a controlled preservation time under room light, but also can be erased on demand by flood UV irradiation, which are promising for advanced anti-counterfeiting such as shelf-life based security and erasable encryption.

MoS2 Decorated Silver Nanowire-Reduced Graphene Oxide Aerogel Micro-Particle for Thermally Conductive Polymer Composites with Enhanced Flame Retardancy.

Multifunctional polymer composites with efficient heat dissipation and flame retardancy are highly desirable in the electronic industry. Here, by the combination of hydrothermal reaction and in situ fragmentation, molybdenum disulfide (MoS2 ) decorated silver nanowires (AgNWs) and 3D reduced graphene oxide (RGO) (AgNW-RGO@MoS2 ) aerogel micro-particles (AMPs) are successfully prepared. When the above AMP is introduced to epoxy (EP) resin by the simple blending method, a polymer composite with continuous thermally conductive pathways and flame barrier layers is achieved. With an AMP loading of 4.0 vol.%, the polymer composite displays superior enhancement in thermal conductivity up to 420%. Compared to neat EP, the peak heat release rate and total heat release decreases by 61.1% and 58.8%, respectively. This work provides new insights into the design and large-scale fabrication of multifunctional polymer composites for efficient thermal management materials.

MicroRNA Profile of Human Bone Marrow Mesenchymal Stem Cells during Hepatic Differentiation and Therapy.

Background and Aims: MicroRNAs (miRNAs) play important roles in hepatocyte differentiation from human bone marrow mesenchymal stem cells (hBMSCs) and the therapeutic application in vivo. However, the mechanisms of miRNA regulation are still unknown. This study aimed to profile the miRNA basis for improving the function of hBMSC-differentiated hepatocyte-like cells (hBMSC-Heps). Methods: Characteristic miRNAs of hBMSC-Heps were identified by transcriptome sequencing and validated by quantitative real-time polymerase chain reaction (qRT-PCR). An in vivo hBMSC transplantation model was used to assess the regulatory effects of miRNAs on liver regeneration during hBMSC therapy in pigs with fulminant hepatic failure (FHF). The biological functions of significant miRNA molecules were confirmed by transfection of miRNA activators or inhibitors into hBMSCs during hepatogenic differentiation. Results: The transcriptome of hBMSC-Heps showed characteristics distinct from those of undifferentiated hBMSCs. A total of 77 miRNAs were significantly differentially expressed in hBMSC-Heps at day 10 and day 20 after hBMSC differentiation that were directly related to the functions of hepatocytes. Among the top 10 significantly differentially expressed and the top 10 most abundant miRNAs, nine miRNAs that exhibited a pattern of gradual change were chosen for further analysis. The expression of nine miRNAs was confirmed by qRT-PCR in vitro and showed the same changing trends in vivo in an hBMSC transplantation model in pigs. Functional experiments with these miRNAs showed that activators of hsa-miR-26b-5p and hsa-miR-148a-3p and an inhibitor of hsa-miR-423-3p were sufficient to improve the differentiation of hBMSCs into hepatocyte-like cells. Conclusions: Transcriptome profiles of miRNA revealed the basis of the differentiation and development of hBMSC-Heps. Manipulation of three miRNAs (hsa-miR-26b-5p, hsa-miR-148a-3p and hsa-miR-423-3p) significantly improved hepatocyte generation and liver regeneration, indicating the potential of these miRNAs for future clinical applications.

Development and validation of a new prognostic score for hepatitis B virus-related acute-on-chronic liver failure.

BACKGROUND & AIMS: Early determination of the prognosis of patients with hepatitis B virus-related acute-on-chronic liver failure (HBV-ACLF) is important to guide clinical management and decrease mortality. The aim of this study was to develop a new simplified prognostic score to accurately predict outcomes in patients with HBV-ACLF. METHODS: Prospective clinical data from 2,409 hospitalized patients with acute deterioration of HBV-related chronic liver disease were used to develop a new prognostic score that was validated in an external group. RESULTS: A total of 954 enrolled patients with HBV-ACLF were diagnosed based on the Chinese Group on the Study of Severe Hepatitis B-ACLF (COSSH-ACLF) criteria. Six predictive factors were significantly related to 28-day mortality and constituted a new prognostic score (=1.649×ln(international normalized ratio)+0.457×hepatic encephalopathy score+0.425×ln(neutrophil)+0.396×ln(total bilirubin)+0.576×ln(serum urea)+0.033×age). The C-indices of the new score for 28-/90-day mortality (0.826/0.809) were significantly higher than those of 4 other scores (COSSH-ACLF, 0.793/0.784; CLIF-C ACLF, 0.792/0.770; MELD, 0.731/0.727; MELD-Na, 0.730/0.726; all p <0.05). The prediction error rates of the new score for 28-day mortality were significantly lower than those of the 4 other scores: COSSH-ACLF (15.9%), CLIF-C ACLF (16.3%), MELD (35.3%) and MELD-Na (35.6%). The probability density function evaluation and risk stratification of the new score also showed the highest predictive values for mortality. These results were then validated in an external cohort. CONCLUSION: A new prognostic score based on 6 predictors, without an assessment of organ failure, can accurately predict short-term mortality in patients with HBV-ACLF and might be used to guide clinical management. LAY SUMMARY: Hepatitis B virus-related acute-on-chronic liver failure (HBV-ACLF) is a complex syndrome that is associated with a high short-term mortality rate. We developed a simplified prognostic score for patients suffering from this condition based on a prospective multicentre cohort. This new score had better predictive ability than 4 other commonly used scores.

Synthesis and evaluation of novel fluorinated hematoporphyrin ether derivatives for photodynamic therapy.

A photosensitizer with high phototoxicity, suitable amphipathy and low dark toxicity could play a pivotal role in photodynamic therapy (PDT). In this study, a facile and versatile approach was adopted to synthesize a series of novel fluorinated hematoporphyrin ether derivatives (I1-I5 and II1-II4), and the photodynamic activities of these compounds were studied. Compared to hematoporphyrin monomethyl ether (HMME), all PSs showed preferable photodynamic activity against A549 lung tumor cells. The longest visible absorption wavelength of these compounds was approximately 622 nm. Among them, II3 revealed the highest singlet oxygen yield (0.0957 min-1), the strongest phototoxicity (IC50 = 1.24 µM), the lowest dark toxicity in vitro, and exhibited excellent anti-tumor effects in vivo. So compound II3 could act as new drug candidate for photodynamic therapy.

Cobalt-Mediated Switchable Catalysis for the One-Pot Synthesis of Cyclic Polymers.

A cobalt salen pentenoate complex [salen=(R,R)-N,N'-bis(3,5-di-tertbutylsalicylidene)-1,2-cyclohexanediamine] is rationally designed as the catalyst for the ring-opening copolymerization (ROCOP) of epoxides/anhydrides/CO2 . Via migratory insertion of carbon monoxide (CO) into the Co-O bonds, the ROCOP-active species α-alkene-ω-O-CoIII (salen) can be rapidly and quantitatively transformed into α-alkene-ω-O2 C-CoIII (salen) telechelic linear precursors. Upon dilution of reaction mixtures, the homolytic cleavage of Co-C bonds induced by visible light generates α-alkene acyl radicals that spontaneously undergo intramolecular radical addition to afford organocobalt-functionalized cyclic polyesters and CO2 -based polycarbonates with excellent regioselectivity. The cyclic products can either react with radical scavengers to generate metal-free cyclic polymers or serve as photo-initiators for organometallic-mediated radical polymerization (OMRP) to produce tadpole-shaped copolymers.

Self-Assembled Binary Photonic Crystals under the Active Confinement and Their Light Trapping.

The self-assembly of oppositely charged colloidal ellipsoids and spheres under active confinement is first proposed to achieve long-range ordered photonic crystals. Compared with the conventional passive confinement, a characteristic of the active confinement is that boundaries are movable. Our Brownian dynamics simulations show that dynamic steady structures, similar to quasi-2D colloidal crystals, can be obtained under the strong confinement when the two boundaries periodically oscillate together. The in-plane structures can be regulated by changing the charge ratio of the two kinds of particles. These dynamic steady structures are determined by the minimum electrostatic energy with the aid of increased mobility of confined particles, which are not available in equilibrium. Numerical simulations verify that light can be perfectly confined in this dielectric binary photonic slab without any radiation, which corresponds to a typical optical bound state with divergent lifetime and ultrasharp spectral profile. Given the changeable geometry of this photonic slab, the trapped optical field might be applicable to enhanced light-matter interactions. In addition, for thicker layers, layer-by-layer ordered structures occur spontaneously, driven by the active confinement, while no global order occurs in the passive confinement. Our results show that the boundary motion can become an important factor affecting self-assembled structure and function.

Artificial liver treatment improves survival in patients with hepatitis B virus-related acute-on-chronic liver failure: A case-control matched analysis.

AIM: The artificial liver support system (ALSS) is recognized as a bridge to liver transplantation in hepatitis B virus-related acute-on-chronic liver failure (HBV-ACLF) patients. However, patient survival remains unknown. We aim to assess the effects of ALSS on survival in HBV-ACLF patients. METHODS: The clinical data of HBV-ACLF patients receiving standard medical treatment (SMT) plus ALSS (ALSS group, n = 507) or only SMT (SMT group, n = 417) were collected for survival assessment. The main end-points were cumulative survival rates at days 21, 28, and 90. Four different rigorous analyses were carried out to reduce bias and confounding. RESULTS: In the entire cohort, the cumulative survival rates at days 21, 28, and 90 were significantly higher in patients who underwent ALSS treatment (73.3% vs. 59.6%, 69.2% vs. 56.6%, 56.5% vs. 49.1%, respectively, P < 0.01) than in those who underwent SMT only. In the 276-pair case-control matched cohort, a significantly higher survival rate was also observed in the ALSS group than in the SMT group on days 21, 28, and 90 (72.5% vs. 60.3%, 68.3% vs. 57.4%, 55.9% vs. 48.5%, respectively, P < 0.05), especially in patients with ACLF-1 and -2. By a multivariable-adjusted analysis, ALSS treatment was associated with a significantly lower risk of mortality, especially for ACLF-2 at days 21, 28, and 90. These findings were also confirmed through propensity score matching and inverse probability treatment weighting analysis. CONCLUSIONS: ALSS treatment can improve short-term survival and is associated with a significantly lower risk of short-term mortality in patients with HBV-ACLF, especially ACLF-2.

Transcriptome Profiling Reveals Distinct Phenotype of Human Bone Marrow Mesenchymal Stem Cell-derived Hepatocyte-like cells.

Background: Human bone marrow mesenchymal stem cell-derived hepatocyte-like cells (hBMSC-HLCs) are a promising alternative for primary human hepatocytes (HHs) for treating liver disease. However, the molecular characteristics of HLCs remain unclear. Here, we aimed to clarify the transcriptome characteristics of hBMSC-HLCs for future clinical application. Materials and Methods: hBMSCs were isolated from the bone marrow of healthy volunteers and differentiated into hepatocytes. mRNA sequencing was used in the transcriptome profiling of hBMSC-HLCs, with hBMSCs and HHs as controls. Results: hBMSC-HLCs exhibited a polygonal morphology, glycogen accumulation and albumin expression. A total of 630 upregulated and 1082 downregulated genes were observed in hBMSC-HLCs and HHs compared with undifferentiated hBMSCs. The upregulated genes were mainly involved in hepatic metabolism and inflammatory and immune responses. The downregulated genes were mainly associated with stem cell characteristics (multipotent differentiation, cell cycle regulation, etc.). Confirmatory qRT-PCR of 9 upregulated and 9 downregulated genes with log2 fold changes > 5 showed similar results. In vivo transdifferentiation of hBMSCs in pigs with fulminant hepatic failure confirmed the similarly upregulated expression of 5 hepatogenic genes (TDO2, HP, SERPINA3, LBP and SAA1), showing a 150-fold change in liver tissues at 7 days after hBMSC transplantation. These 5 genes mainly contributed to liver metabolism and inflammation. Conclusion: hBMSC-HLCs possess a hepatic transcriptome profile and express hepatic-specific genes in vitro and in vivo, which might be useful for future clinical applications. The five upregulated genes identified herein could be potential biomarkers for the characterization of hBMSC-HLCs.

Switchable Polymerization Triggered by Fast and Quantitative Insertion of Carbon Monoxide into Cobalt-Oxygen Bonds.

A strategy that uses carbon monoxide (CO) as a molecular trigger to switch the polymerization mechanism of a cobalt Salen complex [salen=(R,R)-N,N'-bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexanediamine] from ring-opening copolymerization (ROCOP) of epoxides/anhydrides to organometallic mediated controlled radical polymerization (OMRP) of acrylates is described. The key phenomenon is a rapid and quantitative insertion of CO into the Co-O bond, allowing for in situ transformation of the ROCOP active species (Salen)CoIII -OR into the OMRP photoinitiator (Salen)CoIII -CO2 R. The proposed mechanism, which involves CO coordination to (Salen)CoIII -OR and subsequent intramolecular rearrangement via migratory insertion has been rationalized by DFT calculations. Regulated by both CO and visible light, on-demand sequence control can be achieved for the one-pot synthesis of polyester-b-polyacrylate diblock copolymers (D<1.15).

Blue- and green-emitting hydrophobic carbon dots: preparation, optical transition, and carbon dot-loading.

In the past decade, hydrophobic fluorescent carbon dots (OCDs) have received little attention, and its potential application and light transition mechanism is seldom explored. Here we report a novel one-step approach for synthesizing blue- and green-emitting hydrophobic fluorescent carbon dots (OCDb and OCDg) by calcinating with the uses of citric acid and hexadecylamine as initial reactants. The optimal conditions for preparing OCDb and OCDg were obtained by using the Taguchi L25 (35) orthogonal array. The highest quantum yield and product yield of OCDs reached 80.2% and 57.1%, respectively, larger than those from most of all the known reports. The fluorescent stability of OCDb and OCDg was excellent under UV irradiation (30 W) for days. The luminescent color of OCDs showed a great dependence on reaction conditions. It is easier to get OCDg via a reaction kept at a high temperature for a long time. The optical transition mechanism was studied for the two kinds of color OCDs, and therefore proposed in combination with their optical properties and surface groups. The reason for light transition is probably related to an appropriate critical ratio and surface density of the C=O and N-H bond in the surface structure of the product. For the OCDg, the concentration matching ratio of N-H and C=O bonds in the surface structure of the green-emitting product is approximately between d/2 and 3d/2, where d is a fixed constant. Lower than or higher than this critical ratio range, the product emits blue light. Based on their high fluorescence quantum efficiency and the advantages mentioned above, these OCDs were then respectively used for preparing hydrophobic fluorescent carbon dot-loading liposomes and acrylate films, both exhibiting a perfect performance with no fluorescence quenching.

Oxygen-Triggered Switchable Polymerization for the One-Pot Synthesis of CO2 -Based Block Copolymers from Monomer Mixtures.

Switchable polymerization provides the opportunity to regulate polymer sequence and structure in a one-pot process from mixtures of monomers. Herein we report the use of O2 as an external stimulus to switch the polymerization mechanism from the radical polymerization of vinyl monomers mediated by (Salen)CoIII -R [Salen=N,N'-bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexanediamine; R=alkyl] to the ring-opening copolymerization (ROCOP) of CO2 /epoxides. Critical to this process is unprecedented monooxygen insertion into the Co-C bond, as rationalized by DFT calculations, leading to the formation of (Salen)CoIII -O-R as an active species to initiate ROCOP. Diblock poly(vinyl acetate)-b-polycarbonate could be obtained by ROCOP of CO2 /epoxides with preactivation of (Salen)Co end-capped poly(vinyl acetate). Furthermore, a poly(vinyl acetate)-b-poly(methyl acrylate)-b-polycarbonate triblock copolymer was successfully synthesized by a (Salen)cobalt-mediated sequential polymerization with an O2 -triggered switch in a one-pot process.

Self-Healing Polymer Electrolytes Formed via Dual-Networks: A New Strategy for Flexible Lithium Metal Batteries.

A novel polymer electrolyte with mechanically robust and self-healing properties was fabricated through a dual-network structure, crosslinked by quadruple hydrogen bonding and chemical bonding. The dynamic ureido-pyrimidinone (UPy) dimers were the first network in the polymer matrix. This group endows the polymer electrolyte with good self-healing capacity and improves the reliability and lifetime of the polymer lithium batteries. The crosslinked polyethylene glycol-bis-carbamate dimethacrylate (PEGBCDMA) is the second network and guarantees dimensional stability and good mechanical properties of the polymer electrolyte. The dual-network self-healing polymer electrolyte (DN-SHPE) exhibits improved ionic conductivity versus the polymer electrolyte fabricated by poly(ethylene glycol) diacrylate (PEGDA). It has high thermal stability (up to 350 °C) and excellent interfacial stability with the electrodes. When the DN-SHPE-based cells were fabricated with LiFePO4 and Li metal, the resulting cells show good reversible specific capacity and considerable rate capability. Moreover, the pouch cell could maintain electrochemical function even under deformation or folding conditions.