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The use of HZSM-5 and modified catalysts for the pyrolysis of lignin to produce aromatics has been extensively investigated. But certain limitations including catalyst deactivation and high-cost modifications still exist. A magnetic field (MF) was used to assist Fe and HZSM-5 catalytic lignin pyrolysis for aromatics production in this study. Product composition analysis revealed that the monocyclic aromatic hydrocarbon (MAH) and benzene, toluene, ethylbenzene, and xylene (BTEX) contents exhibited an upward trend in correlation with the MF intensity. The introduction of a MF significantly affects the improvement of the BTEX yield. Under the conditions of 80 mT MF intensity, 500 °C temperature and 50 mL min−1 carrier gas flow rate, the MAH and BTEX contents reach 32.94% and 27.19%, while the BTEX yield reaches roughly 19.55 mg g−1. Compared to no MF, these values rose by about 1.28, 1.36, and 1.94 times, respectively. Characterization results from XRD, XPS, TPO, N2 adsorption–desorption, and NH3–TPD tests showed that the MF facilitated the deoxidation and fragmentation of macromolecular oxygenates on the surface of Fe, promoting the ingress of smaller molecular compounds into the pores of HZSM-5 and boosting MAH production. Simultaneously, the MF impeded pore blockage in HZSM-5 and kept acidic sites from deactivating due to carbon deposition. This study lays a crucial groundwork for improving advanced technologies aimed at optimizing the utilization of organic solid waste. [ABSTRACT FROM AUTHOR]

Polyelectrolytes with ultra-low glass transition temperatures (Tg) are still a rarity. Herein, we report a series of free-flowing lignin polyelectrolytes with ultra-low Tg in the range of −57–9 °C, namely, deep eutectic supramolecular lignin (DESL). The enabling key principle is to couple the eutectic strategy with supramolecular polymerization, bypassing the exclusive reliance on the large size and flexible cation/anion pairs for flowable polyelectrolytes. Following this principle, various sugars have been successfully integrated with lignosulfonic acid via multiple hydrogen bondings, allowing for bulk yet free-flowing supramolecular materials. These DESLs are processible, adaptive, and compatible to serve as macromolecular solvents and are distinct from traditional polyelectrolyte solutions or chemical modification derivatives. The robustness and versatility of our approach provide a fresh opportunity for booming polyelectrolyte utilization, opening access to a yet unknown fluidic material class. [ABSTRACT FROM AUTHOR]

Developing green and effective solvents is of significant importance for the utilization of lignin. Here, we demonstrated that biomass-derived polar aprotic solvents can serve as co-solvents with poly-deep eutectic solvents (PDESs) for massively dissolving various lignin samples at room temperature. The pristine PDESs were composed of polyethylene glycol derivatives and levulinic acid, while all of them exhibited poor solubility to enzymatic hydrolysis lignin (EHL), sodium lignosulfonate (LS), and organosolv lignin (OL). With the further introduction of polar aprotic solvents, including dimethylisosorbide (DMI), dihydrolevoglucosenone (Cyrene), N-formylmorpholine (NFM), and propylene carbonate (PC), synergy between the polar aprotic solvents and PDESs dramatically increased lignin solubility to 96.82%. PC and DMI were more suitable for assisting the solubilization of EHL and OL, while Cyrene and PC were targeted at the solubilization of LS in PDESs, respectively. Moreover, a new unified co-solvent solubilization mechanism relative to the Kamlet–Taft empirical parameters was proposed. The novel polar aprotic/PDES systems provide a new avenue for boosting the high utilization of lignin. [ABSTRACT FROM AUTHOR]

The rapid and reliable determination of thrombomodulin (TM) is of great significance for the diagnosis of disseminated intravascular coagulation, thrombosis and others. This work exhibits an electrochemiluminescent (ECL) sensor, which was prepared using Ru(bpy)32+ encapsulated by MIL-NH2-101(Al) nanocomposites for the sensitive detection of the new-thrombus marker thrombomodulin (TM) for the first time. Specifically, on one hand, with the advantages of high specific surface area, large hollow porous structure and favorable biocompatibility, MIL-NH2-101(Al) could load a large amount of luminescent Ru(bpy)32+ and thereby greatly enhance the ECL signal of the immunosensor. On the other hand, K2S2O8 is used as co-reactant to form a reduction–oxidation ECL system for cathodic ECL detection with strong anti-interference capacity. The experimental results show that the ECL signal intensity of the Ru(bpy)32+@MIL-NH2-101(Al)-based immunosensor decreased with the immunocapturing of TM, exhibiting a linear detection concentration ranging from 1 × 10−5 to 10 μg mL−1 and the limit of detection (LOD) of 8.2 × 10−6 μg mL−1 (S/N = 3). With its ideal stability, selectivity and reproducibility, the proposed ECL immunosensor can provide excellent aid and shows great promise for the detection of TM. [ABSTRACT FROM AUTHOR]

Liquid metal (LM)-based nano-inks are facing challenges for their use in wearable electronics due to their low colloidal/chemical stability, cost, potential hazards, and the lack of multifunction. Here, we demonstrate a dialdehyde xylan (DAX) stabilizing LM ink encompassing low-cost, long-term stability, biocompatibility, and catalytic activity. DAX with a high molecular weight was obtained by converting the industrial pulping byproducts, xylan, in water directly with sodium periodate (NaIO4) at room temperature. The DAX/LM ink revealed remarkable chemical and colloidal stability for a period of approximately 7 d, as well as high affinity to various substrates. Compared with other LM nano-inks, the DAX/LM ink showed a remarkable catalytic feature for ultrafast polymerization of vinyl monomers, as well as chemical reactivity to construct double network (DN) gels with motion-sensing properties. This work holds promises for the high value-added utilization of lignocellulosic biomass in the fields of future flexible electronic materials. [ABSTRACT FROM AUTHOR]

A turn-on spiropyran functionalized fluorescein derivative (FMC) is developed for targeting HS− in mitochondria. FMC exhibits very weak fluorescence at 525 nm under the excitation of 470 nm in aqueous solution due to its colorless spiropyran form; upon addition of HS−, a strong fluorescence enhancement by 6.4-fold is observed with spirocycle-opened merocyanine form and rapid trapping kinetics for HS−. FMC has good biocompatibility and high selectivity towards HS− with a detection limit of 88.2 nM and is very sensitive among the reported H2S fluorescent probes. Moreover, the significant colocalization of FMC with Mito Tracker® Deep Red FM in human laryngeal epidermoid carcinoma (HEp-2) cells and the Pearson correlation coefficient of 0.87 together demonstrate that FMC can target and image the endogenous H2S in the mitochondria of living cells. [ABSTRACT FROM AUTHOR]

The development of effective solvents for lignin is of high importance. Herein, two types of novel deep eutectic solvents (DESs) were designed employing lactic acid and N-methylthiourea as hydrogen bond donors and four different quaternary ammonium salts as hydrogen bond acceptors. The designed DESs could efficiently dissolve different types of lignin, including dealkaline lignin (DAL), enzymatic hydrolysis lignin (EHL), sodium lignosulfonate (SL), and organosolv lignin (OL). The investigation of the mechanism revealed that the functional groups in the DESs significantly affected their ability to dissolve lignin, and a positive correlation was found between the solubility of lignin and the subtraction value of α and β (Kamlet–Taft empirical parameters) for the dissolution of EHL, DAL and OL. Additionally, the unique dissolution behaviour of SL was due to its salt-like structure. [ABSTRACT FROM AUTHOR]

Highly fluorescent carbon dots (CDs) are prepared by a one-step microwave heating method using citric acid, l-cysteine and dextrin as the precursors. The average size of the CDs is 2.61 nm with good water dispersibility and photostability. Compared with undoped CDs, small amounts of nitrogen (N) and sulfur atom (S) co-doped CDs exhibit a red shift of the absorption spectra to the visible region and lead to a high quantum yield of 22%. Due to the large amount of carboxyl and hydroxyl groups (−COOH and −OH) on the surface of the CDs, Cu2+ is selectively detected in aqueous solution at pH 7.0 with a detection limit as low as 20 nM, which is much lower than the maximum concentration of Cu2+ in drinking water (∼20 μM) permitted by the US Environmental Protection Agency (EPA). Moreover, the application in tap water samples further demonstrates that the as-synthesized CDs are good candidates for the monitoring of Cu2+ in environmental water samples. [ABSTRACT FROM AUTHOR]

An organic salt based on double 1,3,4-oxadiazole derivatives as fluorophores and BAPTA as a receptor has been designed for detection of Cd2+. The fluorescent probe exhibits high selectivity for Cd2+ and a low detection limit of 20 nM in aqueous solution, making it useful for Cd2+ imaging in living MCF-7 cells. [ABSTRACT FROM AUTHOR]

A novel vis-NIR neutral pH probe ESCY was facilely prepared by the ethylene bridging of N-alkylated indolium and 4-(diphenylamino)benzaldehyde. The pH titration indicated that ESCY displayed a remarkable emission enhancement in the vis-NIR fluorescence region (λem = 650 nm) when the pH is decreased from 10.00 to 5.00, and the pKa value was 7.38 near the physiological pH, which is valuable for near-neutral cytosolic pH research. The probe exhibited strong pH-dependent behavior and responded linearly and rapidly to minor pH fluctuations within the range of 6.50–8.20. In addition, ESCY displayed a notably large Stokes shift of 120 nm, high reversibility and could effectively avoid the influence of autofluorescence in biological systems. The confocal fluorescent microscopic images of subcellular distribution and the detection of pH in SW480 cells were achieved successfully, suggesting that ESCY has excellent cell membrane permeability and could image near-neutral cytosolic pH fluctuations in live cells with negligible autofluorescence. [ABSTRACT FROM AUTHOR]

The rapid and reliable determination of thrombomodulin (TM) is of great significance for the diagnosis of disseminated intravascular coagulation, thrombosis and others. This work exhibits an electrochemiluminescent (ECL) sensor, which was prepared using Ru(bpy) 3 2+ encapsulated by MIL-NH 2 -101(Al) nanocomposites for the sensitive detection of the new-thrombus marker thrombomodulin (TM) for the first time. Specifically, on one hand, with the advantages of high specific surface area, large hollow porous structure and favorable biocompatibility, MIL-NH 2 -101(Al) could load a large amount of luminescent Ru(bpy) 3 2+ and thereby greatly enhance the ECL signal of the immunosensor. On the other hand, K 2 S 2 O 8 is used as co-reactant to form a reduction-oxidation ECL system for cathodic ECL detection with strong anti-interference capacity. The experimental results show that the ECL signal intensity of the Ru(bpy) 3 2+ @MIL-NH 2 -101(Al)-based immunosensor decreased with the immunocapturing of TM, exhibiting a linear detection concentration ranging from 1 × 10 -5 to 10 μg mL -1 and the limit of detection (LOD) of 8.2 × 10 -6 μg mL -1 (S/N = 3). With its ideal stability, selectivity and reproducibility, the proposed ECL immunosensor can provide excellent aid and shows great promise for the detection of TM.

A turn-on spiropyran functionalized fluorescein derivative (FMC) is developed for targeting HS- in mitochondria. FMC exhibits very weak fluorescence at 525 nm under the excitation of 470 nm in aqueous solution due to its colorless spiropyran form; upon addition of HS-, a strong fluorescence enhancement by 6.4-fold is observed with spirocycle-opened merocyanine form and rapid trapping kinetics for HS-. FMC has good biocompatibility and high selectivity towards HS- with a detection limit of 88.2 nM and is very sensitive among the reported H2S fluorescent probes. Moreover, the significant colocalization of FMC with Mito Tracker® Deep Red FM in human laryngeal epidermoid carcinoma (HEp-2) cells and the Pearson correlation coefficient of 0.87 together demonstrate that FMC can target and image the endogenous H2S in the mitochondria of living cells.

Nitrogen doped carbon dots (N-CDs) have been prepared via a one-pot hydrothermal method by using formamide and o -phenylenediamine as the carbon precursors. The as-fabricated N-CDs display excellent water dispersibility, good biocompatibility and anti-photobleaching properties. A strong emission band with an emission maximum ( λ fl max ) of 556 nm is observed under 450 nm excitation, and a large Stokes shift of 106 nm is presented. However, the fluorescence is quenched by the addition of Fe 3+ ; a good linearity is shown in the range of 0-65 μM with a detection limit as low as 0.85 μM. Fortunately, the quenched fluorescence could be recovered rapidly by the addition of monohydrogen phosphate (HPO 4 2- ) due to the formation of the stable [N-CDs-Fe 3+ -HPO 4 2- ] complex, and a good linearity is exhibited in the range of 0-60 μM with a low detection limit of 0.80 μM for HPO 4 2- . A novel "on-off-on" fluorescence response is seen with an obvious color change from yellow-crimson-yellow by the naked eye. In addition, the confocal microscopy images suggest that the as-synthesized N-CDs could serve as a sensitive nanosensor for Fe 3+ and HPO 4 2- detection, implying the diverse potential application of N-CDs in the biomedical field., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

A ratiometric fluorescent probe for Ca(2+) based on 1,3,4-oxadiazole derivative has been designed and developed. The probe exhibits a large Stokes shift of 202 nm and a highly selective ratiometric emission response (490/582 nm) to Ca(2+) over other metal cations. Additionally, the probe can readily reveal the changes of intracellular Ca(2+) concentration in living human umbilical vein endothelial cells.

A novel fluorescence aptasensor based on DNA charge transport for sensitive protein detection has been developed. A 15nt DNA aptamer against thrombin was used as a model system. The aptamer was integrated into a double strand DNA (dsDNA) that was labeled with a hole injector, naphthalimide (NI), and a fluorophore, Alexa532, at its two ends. After irradiation by UV light, the fluorescence of Alexa532 was bleached due to the oxidization of Alexa532 by the positive charge transported from naphthalimide through the dsDNA. In the presence of thrombin, the binding of thrombin to the aptamer resulted in the unwinding of the dsDNA into ssDNA, which led to the blocking of charge transfer and the strong fluorescence emission of Alexa532. By monitoring the fluorescence signal change, we were able to detect thrombin in homogeneous solutions with high selectivity and high sensitivity down to 1.2 pM. Moreover, as DNA charge transfer is resistant to interferences from biological contexts, the aptasensor can be used directly in undiluted serum with similar sensitivity as that in buffer. This new sensing strategy is expected to promote the exploitation of aptamer-based biosensors for protein assays in complex biological matrixes.