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Colloidal photonic crystals (PCs), consisting of highly ordered monodisperse nanoparticles, have been carried out a great deal of research in recent decades due to the attributes of readable signal, easy modification and low cost. With these unique features, colloidal PCs have also gradually become a focus of candidates applied in sensing fields. In this review, an overview of recent advances in colloidal PCs including self-assemblies and sensing applications is illustrated. With respect to the development in self-assemblies of colloidal PCs, the review concentrates on the summary of responsive mechanisms, detection methods, responsive materials, unit cells and fabrication methods. In terms of advances in sensing application of colloidal PCs, various types of sensors are summarized based on the kinds and applications of target analytes. Furthermore, the current limitations and potential future directions of colloidal PCs in self-assemblies and sensing areas are also discussed. Image 1 • Colloidal PCs have come to the fore due to the unique feature of structures. • Recent developments in self-assemblies of colloidal PCs are highlighted. • Recent advances in sensing applications of colloidal PCs are introduced. • The prospect and current limitation of colloidal PCs are summarized. [ABSTRACT FROM AUTHOR]

Abstract: Conjugated polymers have recently attracted a great deal of attention for applications in photodynamic therapy (PDT) because of their light‐harvesting capability, efficient energy transfer, and singlet oxygen generation properties. This review describes recent advances in PDT development, including therapeutic mechanisms of PDT in cancer treatments, light excitation methods, and especially recent advances of conjugated polyelectrolytes and conjugated polymer nanoparticles as photosensitizers. The future direction on PDT and further development of conjugated polymer photosensitizers are discussed. The aim of this review is to stimulate innovative ideas to synthesize a new generation of conjugated polymer photosensitizers and promote their translation to clinical applications of PDT. [ABSTRACT FROM AUTHOR]

Stem cell therapy is rapidly moving toward translation to clinical application. To elucidate the therapeutic effect, a robust method that allows tracking of the stem cells over an extended period of time is required. Herein, semiconducting polymer dots (Pdots) are demonstrated for their use in bright labeling and tracking of human mesenchymal stem cells (MSCs) in vitro and in vivo. The Pdots coated with a cell-penetrating peptide (R8) showed remarkable endocytic uptake efficiency that was 15 times higher than that of carboxyl Pdots and more than 200 times than that of bare Pdots. The Pdot-labeled MSCs can be traced for 15 generations in vitro and tracked over 2 weeks in vivo after subcutaneous transplantation. The labeled MSCs administered through the tail vein were preferentially accumulated in the lung; this was distinctive from the distribution of free Pdots, which were primarily distributed in the liver. Based on the properties of bright labeling, excellent tracking capability, and great biocompatibility, the Pdots will be valuable in the applications of stem cell biology and regenerative medicine. [ABSTRACT FROM AUTHOR]

Molecularly imprinted polymer hollow spheres (MIHSs) were produced by using hexanitrohexaazaisowurtzitane (HNIW or CL-20) as a template, silica nanospheres as a sacrificial matrix, acrylamide as a functional monomer, ethylene glycol dimethacrylate as a cross-linker and acetonitrile as a porogen at 4 °C under UV irradiation. This sorbent was applied to the selective solid-phase extraction (SPE) of several explosives simultaneously by using a newly-developed SPE procedure. For the first time, 2,4,6-trinitrotoluene (TNT), 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX), 1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane (HMX) and CL-20 were selectively extracted and determined simultaneously from simulated post-blast samples prepared from motor oil and vacuum pump oil. The matrix effects were successfully eliminated and accurate quantization was achieved. When the loading amounts of HMX, RDX, TNT and CL-20 were, respectively, below 10, 2, 5 and 20 nmol for 100 mg of MIHS, these explosives were almost retrieved completely (above 98%). For the MIHSs and non-imprinted polymer hollow spheres (NIHSs), in acetonitrile and methanol, the imprinting factors (IFs) of CL-20 and tetraacetyldibenzylhexaazaisowurtzitane (TADB, a structural analogue of CL-20) changed dramatically, from 7.75 to 1.57 and 0.88 to 2.39, respectively. It highlighted the significant effect of solvents on imprinted sites. [ABSTRACT FROM AUTHOR]

A novel solanesol extraction method based on molecularly imprinted polymer (MIP) as the Flash chromatography stationary phase was established and evaluated. Spherical MIP particles in a size range of 250–350 μm (d (0.5) = 320 μm) for solanesol were synthesized by suspension polymerization, with imprinting factor of 3.9. The MIP particles (5.5 g) were packed in common Teflon column as the stationary phase while the sample solution and elution solvent were confirmed as methanol and methanol/acetic acid solution (80/20, v/v), loading at 4 ml/min and eluting 8 ml/min, respectively. Under the optimal chromatographic conditions, the adsorption capacity of the MIP-Flash column was determined as 107.3 μmol/g, and in each process, 370.8 mg purified solanesol (98.4%) could be obtained from the extract (20 mM, 40 ml) of tobacco leaves (14.7 g), and the yield of solanesol was 2.5% of the dry weight of tobacco leaves. The results reported here confirm the feasibility to extract highly purified active ingredients directly from natural products on a large scale by MIP-Flash chromatography. [ABSTRACT FROM AUTHOR]

A simple method was developed to prepare ultra-thin, large-area, free-standing two-dimensional (2D) polymethylmethacrylate (PMMA) colloidal crystal array monolayers by assembling PMMA colloids suspended in toluene on water surface. Diffraction of the free-standing films could be adjusted through the particle size or operation time. [ABSTRACT FROM AUTHOR]

A novel hydrogel film with a highly ordered macropore monolayer on its surface was prepared by templated photo-polymerization of hydrogel monomers on a two-dimensional (2D) polystyrene colloidal array. The 2D inverse opal hydrogel has prominent advantages over traditional three-dimensional (3D) inverse opal hydrogels. First, the formation of the 2D array template through a self-assembly method is considerably faster and simpler. Second, the stable ordering structure of the 2D array template makes it easier to introduce the polymerization solution into the template. Third, a simple measurement, a Debye diffraction ring, is utilized to characterize the neighboring pore spacing of the 2D inverse opal hydrogel. Acrylic acid was copolymerized into the hydrogel; thus, the hydrogel responded to pH through volume change, which resulted from the formation of the Donnan potential. The 2D inverse opal hydrogel showed that the neighboring pore spacing increased by about 150 nm and diffracted color red-shifted from blue to red as the pH increased from pH 2 to 7. In addition, the pH response kinetics and ionic strength effect of this 2D mesoporous polymer film were also investigated. [ABSTRACT FROM AUTHOR]

The solubility of racemic potassium2-(1-hydroxypentyl)-benzoate(dl-PHPB) in methanol, ethanol, n-propanol, isopropyl alcohol, ethyl acetate, and acetone from 298.15to 333.15 K was measured by an equilibrium method. The solubilitydata of dl-PHPB in six different solvents was correlatedby the modified Apelblat equation. The correlation coefficients wereobserved in the range of 0.993 to 0.998, indicating a good fit. Theresults showed that the mole fraction solubility of dl-PHPB in methanol (6.22 × 10–2), ethanol (2.58× 10–2), n-propanol (2.39× 10–2), and isopropyl alcohol (6.72 ×10–3) was significantly higher than in acetone (2.58× 10–4) and ethyl acetate (8.02 × 10–5) at 298.15 K. The experiment data would be usefulfor optimizing purification and recrystallization processes of dl-PHPB in industry. [ABSTRACT FROM AUTHOR]

Abstract: Molecular imprinting is a useful method to make enzyme mimics for protein recognition. Classic protein imprinting involves entrapping proteins within polysiloxane or polyacrylamide, but due to the rigidity of the recognition sites and the limited interaction between proteins and small molecule monomers, they often have unsatisfactory capacity, poor reproducibility and low specificity. In this report, “soft” and flexible recognition sites that can allow “induced fit” of the target proteins were created by a novel surface imprinting technique. When about 25% of the template proteins were removed, the unremoved proteins created “soft” and flexible loops that can lock into place upon protein rebinding, which provides additional favorable interactions between the rebind proteins and the imprinted sites. The adsorption capacity of the surface imprinted silica is 24.8×10−7 mol/g. The “soft” recognition sites can distinguish target hemoglobin from other proteins such as bovine serum albumin, Cytochrome C and RNase A. [Copyright &y& Elsevier]

Abstract: To assess the potential risks associated with the environmental exposure of β-lactam antibiotics (BLAs), the monitoring of the occurrence, distribution, and fate of these emerging contaminants in the environment is required. Herein, we demonstrate a molecularly imprinted solid-phase extraction (MISPE) method for selective and reliable screening of trace BLAs in river and tap water. By developing a low-temperature photopolymerization, highly selective molecularly imprinted polymers (MIPs) for five BLAs (penicillin G, amoxicillin, ampicillin, nafcillin and mezlocillin) were synthesized. Nafcillin was chosen as a pseudo template to make the MIP sorbent (Nafc-MIP), which was used in pseudo-template MISPE for preconcentration of the other four BLAs from river and tap water. The application of pseudo-template MISPE overcomes the template bleeding, which significantly elevates the sample background and restricts the application of MIP for detection of the target BLA below 2μg/L. The average recoveries of BLAs are in the range of 60–90% when Nafc-MIP was adopted as the selective MISPE sorbent. The developed method was validated, and applied to the screening of trace β-lactam antibiotics in river and tap water. The linearity of the calibration curve for each BLA was observed over the range of 0.1–20μg/L (r >0.998). The β-lactam antibiotics were found within the range of 0–9.56μg/L in river water at the downstream of antibiotics manufacturers, and none were detected in the tap water. [Copyright &y& Elsevier]

A polymeric catalyst was synthesized by co-polymerizing 4(5)-vinylimidazole and itaconic acid with trimethylpropanol trimethacrylate micro spheres. The catalyst obtained catalysed the transesterification process between p-nitrophenyl acetate and hexanol with maximal initial velocity(νmax) of 4.73 ± 0.47 μ M min−1 mg−1, and turnover rate ( kcat) of 8.67 min−1. Using p-nitrophenyl acetate as template, molecular imprinting process enhanced the νmax of the polymeric catalyst 3-fold. Each imprinted site can be considered as a single molecular reaction vessel, and achieved a kcat of 169 min−1 towards the conversion of p-nitrophenyl acetate in hexanol. Copyright © 2004 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Abstract: A computational approach was developed to optimize the monomer formulation of molecularly imprinted catalysts. A virtual library of the intermediates of a lipase-catalysed transesterification process was constructed using Chem3D software with p-nitrophenyl acetate as substrate. The energies of the intermediates were minimized using the semi-empirical MOPAC method with the most stable intermediate expected to lead to a higher turn over rate. According to the optimization results, a MIC was prepared by co-polymerising 4(5)-vinylimidazole and itaconic acid with trimethylpropanol trimethacrylate micro spheres in the presence of p-nitrophenyl acetate. The MIC achieved of the transesterification process between p-nitrophenyl acetate and hexanol with a turn over rate of 26.2min-1, and showed substrate specificity towards its template with a 6.5-fold preference for p-nitrophenyl acetate over p-nitrophenyl salicylate. [Copyright &y& Elsevier]

Hereunder, we pioneered the synthesis of Copper Oxide nanoparticles (CuO NPs) utilizing Tragacanth gum (TG). The NPs were characterized using advanced techniques and assessed for different pharmaceutical and environmental perspectives. The successful formation of a colloidal NPs solution was confirmed by the appearance of a distinct black color and a distinct peak at 260 nm in UV–Visible spectrophotometry. The FTIR analysis unveiled a spectrum of functional groups responsible for the reduction and stabilization of CuO NPs. Dynamic Light Scattering (DLS) and Transmission Electron Microscopy (TEM) revealed size of NPs as 36.24 nm and 28 ± 04 nm respectively. Energy Dispersive X-ray (EDX) Analysis indicated weight percentages of 70.38 % for Cu and 18.88 % for O, with corresponding atomic percentages. The X-ray Diffraction (XRD) analysis revealed the orthorhombic crystal structure of the prepared CuO NPs. Antimicrobial assessments through disc-diffusion assays demonstrated significant zones of inhibition (ZOI) against gram-positive bacterial strains (Bacillus Halodurans and Micrococcus leutus) and a gram-negative bacterial strain (E. coli). Against the fungal strain Aspergillus niger , a ZOI of 18.5 ± 0.31 mm was observed. The NPs exhibited remarkable antioxidant potential determined through 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and H 2 O 2 scavenging assays. At a concentration of 3 mg/mL, the NPs demonstrated biofilm inhibition rates of 96 %, 90 %, 89.60 %, and 72.10 % against Micrococcus luteus , Bacillus halodurans , MRSA and E.coli respectively. Furthermore, the CuO NPs showed a high photocatalytic potential towards the degradation of safranin dye under sunlight irradiation. In conclusion, the findings underline the promising multifunctional properties of TG-based CuO NPs for different practical applications. [ABSTRACT FROM AUTHOR]

The cylindrical surface with Bragg-enhanced Fresnel reflectivity constructed from non-close-packed photonic crystals (NPCs) was designed for spectral selectivity and optical gain, which broke through the limitations of traditional Fresnel curved mirror with lowest central reflectivity and inability to perform spectral selectivity, and was conducive to expending the application of Fresnel mirror in the fields of signal transmission, optical measurement and instrument design. [Display omitted] According to the Fresnel theory, the reflectivity intensity of spherical and cylindrical convex surfaces decreases from their edge to center, and it is noteworthy and interesting for optical gain to study the enhancement of center reflectance. In this paper, a polydimethylsiloxane (PDMS) − encapsulated cylindrical non-closed-packed photonic crystals (NPCs) composite with Bragg-enhanced Fresnel reflectance was designed for spectral selectivity and optical gain. Theoretically and experimentally, the periodically ordered structure of NPCs achieved high-reflection of light in photonic bandgap and high-transmission in other bands, which enhanced Fresnel reflectivity of the convex center to specific bands. Furtherly, the cylindrical NPCs hydrogel with stretchability was applied for the dynamic tuning of optical signals. The reflection peak of the PDMS-encapsulated cylindrical NPCs composite blue-shifted from 608 nm to 413 nm with 50 % tensile strain and achieved a rapid transition of structural color from orange to blue-violet in 60 cycles. The new kind of photonic crystals composite for optical gain and spectral selection broke through the limitations of traditional Fresnel curved mirrors with the lowest central reflectivity and inability to perform spectral selectivity, and have great significance and application prospects in fields of signal transmission, optical measurement, and instrument design. [ABSTRACT FROM AUTHOR]

Examines the role of molecule imprinting polymer with high chiral selectivity. Indication of functional monomers; Stability of acetonitrile; Purification of the polar solvent.

In this study, mono-sized anion-exchange microspheres with polyglycidylmethacrylate were engineered and processed to introduce magnetic granules by penetration–deposition approaches. The obtained magnetic microspheres showed a uniform particle diameter of 1.235 μm in average and a good spherical shape with a saturation magnetic intensity of 12.48 emu/g by VSM and 12% magnetite content by TGA. The magnetic microspheres showed no cytotoxicity when the concentration was below 10 μg/mg. The magnetic microspheres possess respective adsorption capacity for three proteins including Bovine albumin, Hemoglobin from bovine blood, and Cytochrome C. These magnetic microspheres are also potential biomaterials as targeting medicine carriers or protein separation carriers at low concentration. [ABSTRACT FROM AUTHOR]

A cross-responsive molecularly imprinted photonic crystal (MIPC) sensor array was established for the detection of RDX, HMX, CL-20 and TNT. The MIPC sensor red shifted and the structural color changed with the increasing concentration of the analytes. Using Pattern Recognition (PR) and principal component analysis (PCA), the sensor array could discriminate four different explosives. • Nitramine explosives were visually detected by molecularly imprinted photonic crystal (MIPC) sensors. • Nitramine explosives could be discriminated by pattern recognition. • Alkaline solution softened MIPC, and improved the mass transfer and the sensitivity. Colorimetric, selective and sensitive screening of explosives is important not only to military action but also to public security. Normal explosives detection is mainly targeted for nitroaromatic compounds, however, ntiramine explosive is used more widely due to its outstanding performance. Herein, molecularly imprinted photonic crystal (MIPC) sensors were made to detect typical nitramine explosives: 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX), cyclotetramethylenete-tranitramine (HMX) and 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20). And 2,4,6-trinitrotoluene (TNT) templated MIPC was also made to discriminate not only nitramines but also nitrobenzene explosives. With explosives concentration increase, the diffraction peak and structure color of MIPC sensors both red shifted within 5 min. By adding alkaline solution, the MIPC sensors were softened, and the mass transfer and the sensitivity were improved. The MIPC sensors could respond to lower than 0.05 mM explosives with the limit of detection of 0.01 mM. A MIPC sensor array with the above MIPCs was constructed to achieve a semi-quantitative detection, and Pattern Recognition with a 48 × 4 multivariate data matrix was using to discriminate different explosive molecules. According to principal component analysis, the response of RDX, HMX, CL-20 and TNT scattered in separate areas, and the sensor array could discriminate with a LOD of 1 mM. [ABSTRACT FROM AUTHOR]

• Hydrogel sensor based on two-dimensional PS colloidal crystal array is developed. • The sensor achieves affinity by the interaction between polymer ligand and target. • The sensor shows high response, selectivity in buffers or body fluids. • It could be controlled by "temperature switch", exhibiting reusability to target It is significant to detect lysozyme both in fundamental research and in clinical practice, since its concentration in body fluid is associated with many diseases. In this study, a new kind of sensor for rapid screening the lysozyme was fabricated based on the two-dimensional (2D) polystyrene colloidal crystal array together with the optimized hydrogel containing acrylamide-based functional groups. Distinct hydrogel volume shrink was observed due to the hydrogel crosslink induced by the functional ligand–protein interactions while the protein bound to the sensor. Therefore, the analyte concentration could be accessed by of the lattice spacing of the 2D colloidal crystal array, which was detected by a change in the Debye diffraction ring diameter. The lysozyme concentration could be easily monitored by measuring the diameter of the Debye diffraction ring in the pathophysiologic range. The particle spacing of 2D colloidal crystal hydrogel sensor increased to about 22 nm while lysozyme concentration increased from zero to 1.0 mg/mL, meanwhile the structural color of the sensor blue shifted from red to yellow. The detection limit was confirmed as 1.38 × 10−3 mg/mL. The selective response to other common proteins in body fluids was also exhibited, indicating the great selective response properties to lysozyme. In addition, the 2D colloidal crystal hydrogel sensor was reusable to detect the lysozyme solution reversibly due to its thermal sensitivity. Moreover, the determination of lysozyme in artificial tears and human urine samples by this sensor demonstrated its feasibility in potential clinical analysis diagnosis. [ABSTRACT FROM AUTHOR]

Exosomes are lipid bilayer vesicles released by cells and serve as natural carriers for cell–cell communication. Exosomes provide a promising approach to the diagnosis and treatment of diseases and are considered as an alternative to cell therapy. However, one main restriction in their clinical application is that the current understanding of these vesicles, especially their in vivo behaviors and distributions, remains inadequate. Here, we reviewed the current and emerging methods for in vivo imaging and tracking of exosomes, including fluorescence imaging, bioluminescence imaging, nuclear imaging, X-ray imaging, magnetic resonance imaging, photoacoustic imaging, and multimodal imaging. In vivo imaging and tracking of exosomes by these methods can help researchers further understand their uptake mechanism, biodistribution, migration, function, and therapeutic performance. The pioneering studies in this field can elucidate many unknown exosomal behaviors at different levels. We discussed the advantages and limitations of each labeling and imaging strategy. The advances in labeling and in vivo imaging will expand our understanding of exosomes and promote their clinical application. We finally provide a perspective and discuss several important issues that need to be explored in future research. This review highlights the values of efficient, sensitive, and biocompatible exosome labeling and imaging techniques in disease theranostics. [ABSTRACT FROM AUTHOR]

As environmental problems increase, there is an urgent demand for new eco-friendly materials. Natural rubber latex (NRL) is a natural material extracted from rubber trees. But its dyeing process with chemical dyes might result in contamination and environmental degradation. Here, NRL is composited with a photonic crystal (PhC) structure by spin coating for the first time. The polymethyl methacrylate (PMMA) photonic nanostructure has been embedded into NRL to give it colors and provide it with optical functionalities. Colors of the composite could be designed and controlled by the sizes of the nanocolloids from 180 nm to 295 nm. The colors have strong stability under external stretching. The 3D natural rubber latex photonic crystal (NRLPC) is used as a responsive material to detect volatile organic compounds (VOCs) including formaldehyde, acetone, toluene, xylene and styrene. With its visual color appearance, biocompatibility and flexibility, NRLPC has promising potential in various sensing applications. [ABSTRACT FROM AUTHOR]

The binding ability of acyclic CB[n]-type receptors M1, M2 and macrocyclic CB[7] toward explosive materials was investigated. Acyclic M2 demonstrates an overall better binding and solubilizing ability, and lower fluorescence in the presence of aromatic explosive compounds, suggesting its future application for the detection of harmful explosive materials. [ABSTRACT FROM AUTHOR]

The systematical thermal behaviors of 3⁃azido⁃1,3⁃dinitroazetidine (ADNAZ) was investigated in this research and compared with those of 1,3,3-trinitroazetidine (TNAZ). The results showed that ADNAZ has a low melting temperature at 78 °C. The final mass loss of ADNAZ under atmospheric pressure is 88.2%. Compared to TNAZ, the replacement of gem-dinitro group with gemazidonitro group makes greatly reduce vapor pressure, melting point as well as the thermal decomposition temperature. The in-situ FTIR spectroscopy of ADNAZ proved the strength of nitro group decreases faster than that of azide group, and a carbonyl group (C=O) was formed at the quaternary carbon center on the azetidine skeleton during heating process. TG/DSC–FTIR–MS quadruple technology was applied, finding small molecular fragments from ADNAZ's thermolysis includes H2 (m/z = 2), H2O (m/z = 18), CN (m/z = 26), HCN (m/z = 27), N2 (m/z = 28), NO (m/z = 30), C2H2O (m/z = 42), HN3 (m/z = 43), CO2 (m/z = 44), and NO2 (m/z = 46). A detailed decomposition mechanism was proposed based on the experimental results. [ABSTRACT FROM AUTHOR]

A novel synthetic method of the 1, 3, 5‐trinitro‐2, 2‐bis(trifluoromethyl)‐1,3,5‐triazinane (2) has been successfully developed. In addition to IR, 1H 13C NMR and elemental analysis, compound 2 was characterized by 15N NMR and X‐ray single crystal diffraction. Due to the introduction of trifluoromethyl, the density of compound 2 is up to 2.04 g⋅cm−3 at 298 K, which is consistent with its crystal density (2.059 g⋅cm−3, 296(2) K). Compound 2 exhibits excellent detonation pressures and velocities (P, 45.6 GPa; vD, 9564 m⋅s−1), as good as exceptional impact and friction sensitivities(IS, 22.5 J; FS, >360 J). Some of these values are better than the current benchmark explosives, such as 1, 3, 5‐trinitrodihydro‐1, 3, 5‐triazine (RDX) and cyclo‐1, 3, 5, 7‐tetramethylenene‐2, 4, 6, 8‐tetranitramine (HMX).It is a potential high energy density material. [ABSTRACT FROM AUTHOR]

G-series nerve agents, such as sarin, tabun, and soman, would cause tremendous harm in military and terrorist attacks, so it is necessary to develop a simple method for the rapid and efficient detection of these hazardous substances. We have developed a tunable acetylcholinesterase (AChE)-functionalized two-dimensional photonic crystal (2D PhC) for the detection of a real nerve agent, sarin. In accordance with the 2D PhC previously prepared by our group, the AChE-functionalized 2D PhC was optimized by adjustment of the amount of monomer in the hydrogel, which not only increased the sensitivity of the 2D PhC, with the detection limit decreasing by two orders of magnitude, but also ensured the structural color spanned the whole visible region in the detection range. A linear relationship between the logarithm of the sarin concentration and the particle spacing of the AChE-functionalized 2D PhC was observed from 7.1 × 10-17 to 7.1 × 10-4 mol/L. The AChE-functionalized 2D PhC also responded to mimics of G-series nerve agents, including dimethyl methylphosphonate, diisopropyl methylphosphonate, and isodipropyl methylphosphonate, to various degrees. The proposed 2D-PhC hydrogel has potential for low-cost, trace-level, and on-site monitoring of other G-series nerve agents. Graphical abstract [ABSTRACT FROM AUTHOR]

Abstract With the development of infrared detection technology, the threat of infrared detection technology to military targets in the battlefield is becoming more and more serious. Novel infrared stealth materials are in urgent demand. Photonic crystals are promising infrared stealth materials because they can prohibit the propagation of electromagnetic waves in a certain frequency range. This paper outlines a simple and fast method to fabricate three-dimensional photonic crystals for stealth material. Monodisperse polystyrene colloid microspheres with a particle size of 2 μm were prepared and used in a gas–liquid interface self-assembly to form a three-dimensional photonic crystal infrared stealth material. The infrared absorption peak wavelengths of the material were 3.30 μm and 3.42 μm. The band gap is in good agreement with the photon forbidden band (3.24–3.44 μm) obtained from simulation and calculation using Rsoft software. The material meets the requirements of an infrared stealth material and realizes the modulation of the infrared radiation characteristics of the detectable band of 3–5 μm. The process provides a simple, economical, fast, and efficient new method for the preparation of large diameter, three-dimensional photonic crystal infrared stealth materials. [ABSTRACT FROM AUTHOR]

Using reduced nicotinamide adenine dinucleotide (NADH) as cofactor, CO 2 can be reduced into methanol catalyzed by formate dehydrogenase (FDH), formaldehyde dehydrogenase (F ald DH) and alcohol dehydrogenase (ADH). However, poor stability of soluble enzymes and the stoichiometric consumption of NADH are major restrictions. Herein, the three enzymes were co-immobilized on a hollow fiber membrane (HFM) module, which was then integrated with a photocatalytic NADH regeneration system to constitute a photo−enzyme coupled system (PECS) for the synthesis of methanol. First, the multi-enzyme immobilization process was optimized and the enzyme-bearing membrane was characterized. Then, the influencing factors of PECS were investigated. The results show that using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) and N -hydroxysuccinimide (NHS) as the activators, a total immobilization efficiency of 64.5% could be obtained, which was superior to sequential immobilization. Under the optimum immobilization conditions, the specific activity reached 0.397 mmol g−1 h−1. For the PECS, NADH concentration, pH value and manipulation parameters had great impacts on the synthesis of methanol. With 10 mmol L−1 NAD+ and H 2 O as electron donor, the methanol yield after 5 h could reach 38.6%, 3.81 times that of enzyme-catalyzed system, proving the PECS was feasible for a continuous synthesis of methanol. [Display omitted] • Three dehydrogenases were co-immobilized on hollow fiber membranes (HFMs). • CO 2 was converted to methanol by the photo-enzyme coupled system (PECS). • H 2 O was used as the electron donor that renders the process green and sustainable. • Methanol yield after 5 h reached 38.6% in PECS, 3.81 folds that of enzyme system. [ABSTRACT FROM AUTHOR]

The structure of hydrazinium 3,5-dinitroamine-1,2,4-triazole (HDNAT) was investigated with infrared (IR), mass spectrometry,13C-NMR, scanning electron microscopy (SEM), and X-ray crystallography. The crystal density of HDNAT was determined as 1.91 g/cm3using X-ray diffraction. The crystal belongs to a monoclinic system with the space group P2(1). The thermal decomposition process of HDNAT was investigated via thermogravimetry–differential thermal analysis (TG-DTA) at a heating rate of 10 K/min and differential scanning calorimetry (DSC) under nonisothermal conditions. The decomposition kinetic and thermodynamic parameters were obtained by the Kissinger and Ozawa method. HDNAT can be analyzed by using a C18 high-performance liquid chromatography (HPLC) column with water : acetonitrile : trifluoroacetic acid (97/3/0.1, v/v/v) as the mobile phase and a capacity factor of 1.33. [ABSTRACT FROM PUBLISHER]

We developed a photonic crystal (PhC) sensor for the quantification of 2,4,6-trinitrotoluene (TNT) in solution. Monodisperse (210 nm in diameter) molecularly imprinted colloidal particles (MICs) for TNT were prepared by the emulsion polymerization of methyl methacrylate and acrylamide in the presence of TNT as a template. The MICs were then self-assembled into close-packed opal PhC films. The adsorption capacity of the MICs for TNT was 64 mg TNT/g. The diffraction from the PhC depended on the TNT concentration in a methanol/water (3/2, v/v) potassium dihydrogen phosphate buffer solution (pH = 7.0, 30 mM). The limit of detection (LOD) of the sensor was 1.03 μg. The color of the molecularly imprinted colloidal array (MICA) changed from green to red with an 84 nm diffraction red shift when the TNT concentration increased to 20 mM. The sensor response time was 3 min. The PhC sensor was selective for TNT compared to similar compounds such as 2,4,6-trinitrophenol, 2,4-dinitrotoluene, 2,6-dinitrotoluene, 2-nitromesitylene, 4-nitrotoluene, 2-nitrotoluene, 1,3-dinitrobenzene, methylbenzene, 4-nitrophenol, 2-nitroaniline, 3-aminophenol and 3-nitroaniline. The sensor showed high stability with little response change after three years storage. This sensor technology might be useful for the visual determination of TNT. [ABSTRACT FROM AUTHOR]

The overexploitation of fossil fuels has led to a significant increase in atmospheric carbon dioxide (CO 2) concentrations, thereby causing problems, such as the greenhouse effect. Rapid global climate change has caused researchers to focus on utilizing CO 2 in a green and efficient manner. One of the ways to achieve this is by converting CO 2 into valuable chemicals via chemical, photochemical, electrochemical, or enzymatic methods. Among these, the enzymatic method is advantageous because of its high specificity and selectivity as well as the mild reaction conditions required. The reduction of CO 2 to formate, formaldehyde, and methanol using formate dehydrogenase (FDH), formaldehyde dehydrogenase (F ald DH), and alcohol dehydrogenase (ADH) are attractive routes, respectively. In this review, strategies for overcoming the common limitations of enzymatic CO 2 reduction are discussed. First, we present a brief background on the importance of minimizing of CO 2 emissions and introduce the three bottlenecks limiting enzymatic CO 2 reduction. Thereafter, we explore the different strategies for enzyme immobilization on various support materials. To solve the problem of cofactor consumption, different state-of-the-art cofactor regeneration strategies as well as research on the development of cofactor substitutes and cofactor-free systems are extensively discussed. Moreover, aiming at improving CO 2 solubility, biological, physical, and engineering measures are reviewed. Finally, conclusions and future perspectives are presented. • Common limitations of enzymatic CO 2 reduction and solutions are presented. • Enzyme immobilization techniques on various supports are elaborated and compared. • Cofactor regeneration pathways, substitutes and free systems are discussed. • Biological, physical, engineering measures for improving CO 2 solubility are reviewed. • Perspectives on enzymatic CO 2 reduction to formate/methanol are put forward. [ABSTRACT FROM AUTHOR]

The determination of lactic acid content has a guiding significance for disease diagnosis or food supervision. Herein, a hydrogel-based three-dimensional photonic crystal (PC) sensor for specific detection of lactic acid is introduced. The hydrogel was prepared by one-step copolymerization of N-isopropylacrylamide and acrylamide in the presence of oxamate derivative 2-((6-acrylamidohexyl) amino)-2-oxoacetic acid (AOA). An obvious color change from orange-red to purple and a 45-nm redshift of the reflection peak were obtained in 3 min when lactic acid concentration increased from 0 to 20 mM. The detection limit was confirmed as 0.1 mM, and the prepared sensor can be reused more than 20 times. Moreover, the affinity and selectivity of AOA to lactic acid were proven by both the interaction energy from density functional theory (DFT) study and the comparison to those of pyruvate and propionic acid. This sensor was proven to be cost-effective and convenient with rapid response time, good reusability, and selectivity. [ABSTRACT FROM AUTHOR]

Parkinson's disease (PD) is a common degenerative disease of the central nervous system among the elderly. Istradefylline, an FDA‐approved adenosine A2A receptor antagonist (anti‐PD drug), has good efficacy. However, it has been reported that the double bond of istradefylline is easily converted into cis‐configuration when exposed to an indoor environment or direct light in a dilute solution. In order to find more stable adenosine A2A receptor antagonists with similar pharmacological efficacy to istradefylline, the compounds series I‐1 (12 compounds) was designed by maintaining the xanthine skeleton of istradefylline unchanged and replacing the trans‐double bond with thiazole or benzothiazole and other biologically active heterocyclic compounds. These compounds were synthesized via multi‐step experiment and successfully confirmed through different characterization techniques for their ability to inhibit cAMP formation in A2AAR overexpressing cells. The thiazole derivative of istradefylline (Compound I‐1‐11, I‐1‐12) exhibited significant activity (IC50 = 16.74 ± 4.11 μM, 10.36 ± 3.09 μM), as compared to istradefylline (IC50 = 5.05 ± 1.32 μM). In addition, the molecular docking of benzothiazole derivatives I‐1‐11 and thiazole derivatives I‐1‐12 with higher inhibition rate were carried out and compared with istradefylline. The molecular docking results showed that I‐1‐11 and I‐1‐12 anchored in the same site as that of XAC (3REY) with predicted affinity binding energy −6.63 kcal/mol and − 6.75 kcal/mol, respectively. Validation through dynamics simulation also showed stable interactions, with fluctuations <3 Å and MM/GBSA energy <−20 kcal/mol. Hence, this study could provide a basis for the rational design of adenosine A2A receptor antagonists with better potency. [ABSTRACT FROM AUTHOR]

[Display omitted] • A pH-responsive discoloration photonic crystal sensor was proposed for amniotic fluid recognition. • The sensor showed the high accuracy and sensitivity, rapid response and visual detection. • Compared with pH test paper, a noticeable color difference and extraordinary accuracy were obtained. In this study, we proposed a pH-responsive photonic crystal hydrogel sensor (PCHs) to conveniently and accurately recognize the amniotic fluid from urine of parturient women, which was constituted by three-dimensional polymethyl acrylamide (PMMA) array and optimized hydrogel. PMMA array was self-assembled by 180 nm monodispersed nanoparticles with vertical sedimentation method. The functional hydrogel containing N-acryloyl phenylalanine (APA), acrylamide (AM) and N, N'-methylene bis(acrylamide) (BIS) as co-monomer and crosslinking agent respectively, was photo-polymerized by the precursor under 365 nm UV light. This hydrogel significantly shrank or swelled corresponding to the acidity and alkalinity of the aqueous solution, which resulted in both the reflection peak position (λ max) of the prepared sensor and its structural color changing with the pH value. The λ max of PCHs redshifted from 514 nm to 606 nm in 60 s while the pH value of testing solution increased from 4.5 to 8.0, which exactly covered the pH value of amniotic fluid and urine. Correspondingly, its structure color gradually changed from pale-green to red ensuring their naked-eye determination. Furthermore, an extremely high sensitivity as 26.3 nm/pH of Δ λ max was obtained which was linearly related to pH value. The prepared sensor possessed steady accuracy and extraordinary sensitivity compared with the pH test strip which was generally used in amniorrhexis diagnosis nowadays besides the advantages of the low cost, simple operation, rapid response and visual detection mode. The reliability of this PCHs was further confirmed by the real sample detection which relative standard deviation was below 5.0 %, suggesting its potential clinical applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • Amino-functionalized polyethylene-silica (APS) composite membranes were fabricated. • Silica loading rate was tunable and reusability of APS after 7 washes was over 99%. • Formate dehydrogenase (FDH) immobilized on APS showed greatly enhanced activity. • Reusability was much improved compared to particles or membrane attached FDH. Enzymatic CO 2 conversion represents a highly efficient, energy-conserving, and environmentally sustainable approach to mitigating the increasing pressure caused by huge carbon emissions and generating valuable products. However, several challenges associate with the process including the instability and recovery difficulty of free enzyme, as well as low solubility of CO 2 in mild conditions. Immobilizing enzyme on the amino-functionalized supports presents a viable solution to these issues. Considering the wide application of polymer hollow fiber membranes in the field of CO 2 gas–liquid membrane contactor and the characteristics of hydrophilic, biocompatible, and high specific surface area of silica nanoparticles, the amino-functionalized polyethylene (PE)-silica (APS) composite membranes were fabricated via different routes. The morphologies, the loading rates of modified SiO 2 and reusability of APS membranes were characterized for a crude screening. Following that, seven kinds of APS membranes were used as the carriers of formate dehydrogenase (FDH) that could catalyze the reduction of CO 2 to formate, and their immobilization efficiency and catalytic performance were compared. The results show that 1# and 2# membranes based on carboxyl-modified PE with a loading rate of 5.5 %∼5.6 % and the reusability of above 99 % were more ideal carriers than others. The enzyme activity recovery rate of APS-immobilized FDH (FDH-APS) was separately 367 % and 256 %, proving the intensification action of carriers on the enzymatic reaction. After 10 cycles of use, the relative activity of two kinds of FDH-APS was around 70 % and 78 %, much higher than corresponding particles or membrane attached FDH (25.3 % and 20.4 %). After storage at 4 °C for 20 days, the relative activity of FDH-APS was 82.7 % and 81.0 %, while it was only 61.4 % for free enzyme. [ABSTRACT FROM AUTHOR]

To investigate the thermal decomposition mechanism between Poly(3-nitratomethyl-3- methyloxetane) (PNIMMO) and 2, 4, 6, 8, 10, 12-Hexanitrohexaazaisowurtzitane (CL-20), the thermal decomposition of PNIMMO, CL-20 and PNIMMO+CL-20 mixture under different conditions was studied using differential scanning calorimetry (DSC), thermogravimetric-differential scanning calorimetry-mass spectra-fourier transform infrared spectrometer (TG-DSC-MS/FTIR) and in-situ FTIR experiments. As a result, the exothermic peak temperature of the PNIMMO+CL-20 mixture shifts to lower values under both closed and open circumstances compared to CL-20. Different kinetic parameters and models were obtained for the three decomposition steps in the mixture. The first step follows the random chain scission model (L2) at α <0.5, and the phase boundary controlled reaction model (R3) at α >0.5. The second/third step is between the random chain scission model (L2) and the first-order reaction model (F1) at α <0.5, and conforms to the first-order reaction model (F1) at α >0.5. Thus, the decomposition of PNIMMO controls the initial speed, while the removal of the nitro group in CL-20 controls the later step. Combined with the analysis of gas products and condensed phase, PNIMMO speeds up the N—NO 2 bond breaking in CL-20 but doesn't alter its initial breakdown route. • The thermal decomposition mechanism between PNIMMO and CL-20 is investigated by various techniques. • PNIMMO+CL-20 mixture decomposes in three steps with different kinetic parameters and kinetic models. • PNIMMO doesn't change the initial decomposition pathway of CL-20. • PNIMMO can accelerates the N—NO 2 bond breaking in CL-20 due to incremental heat and H atoms. [ABSTRACT FROM AUTHOR]

Ion mobility spectrometry (IMS) was explored in the selective detection of nitrobenzene compounds in industrial waste water and surface water, and the selectivity was theoretically elucidated with the transformation energy in the product ion formation reaction. A linear detection range of 0.5–50 ppm and a limit of detection (LOD) of 0.1 ppm were found for 2,4,6-trinitrotoluene (TNT). With the IMS as the detection system of molecularly imprinted polymer (MIP) separation technique, the MIP-IMS system was proved to be excellent method to detect trace amount of nitrobenzene compounds in surface water, in which more than 87% of nitrobenzene compounds could be adsorbed on MIPs with 90–105% of recovery. [ABSTRACT FROM AUTHOR]

Highlights: [•] A fluorescence anisotropy approach for detection of Pb2+ was developed. [•] The strategy was based on binding-induced allosteric conformational change of aptamer probe. [•] The sensing mechanism was established by testing the photoinduced electron transfer interaction. [ABSTRACT FROM AUTHOR]

Flash column chromatography prepacked with molecularly imprinted polymers (MIPs) has been successfully used for the extraction of shikimic acid from Chinese star anise. The shikimic acid imprinted polymer with an adsorption capacity of 21.94 µmol g−1dry polymer and imprinting factor of 4.2 was prepared using the dispersion polymerization method. The capacity of the MIP-Flash column was determined as 23.3 mg g−1using a frontal chromatography method when 10 m mol L−1shikimic acid was eluted through the MIP-flash column at 1.7 mL min−1. The crude extract of Chinese star anise loaded on the column was eluted with ethanol/water (40/60, v/v) to remove the impurities, after elution with methanol/water/acetic acid (32/48/20, v/v/v), purified shikimic acid (>95%) was obtained. The MIP-flash column can be reused for at least 4 rounds with capacity lost less than 15%. It was demonstrated that, compared with HPLC, flash column chromatography prepacked with MIPs is a more rapid, feasible, and economical method for the extraction of active ingredients from plants on a large scale based on the technology of molecular imprinting. [ABSTRACT FROM AUTHOR]

Enzymatic conversion of CO 2 to formate is a highly significant pathway for CO 2 utilization, but current level of conversion efficiency remains unsatisfactory due to low solubility of CO 2 under mild conditions. CO 2 -philic materials can significantly augment the reaction by raising local concentration of substrate. Herein, the intercalated Ti 3 C 2 T x , nano-silica (SiO 2) and carbon nitride (CN) with abundant CO 2 adsorption sites were introduced to fabricate Ti 3 C 2 T x based nanocomposites, Ti 3 C 2 T x /SiO 2 /CN (TSCN), for the first time. As the controls, binary composites including Ti 3 C 2 T x /SiO 2 (TS), Ti 3 C 2 T x /CN (TCN) and SiO 2 /CN (SCN) were also studied. For each kind of material, the composition, structure, morphology, and application performance in the enzymatic CO 2 conversion were characterized and influencing factors were investigated. Among these composites, TSCN exhibited the best application performance and the enzyme reaction was accelerated up to 23.9 times that of the blank system. The value could reach as high as 35.3 after polyethyleneimine (PEI) modification. Following that, PEI modified composites were used as carrier of formate dehydrogenase (FDH) and apparent specific activity was up to 2.8 times that of free enzyme, which could retain 88.2% of the initial value after 10 cycles associated with the structural integrity. This work provides new impetus to CO 2 capture and conversion in a clean and mild way that shows bright application prospects. [ABSTRACT FROM AUTHOR]

Efficient regeneration of nicotinamide adenine dinucleotide (NADH) is of great significance for the application of oxidoreductase-catalyzed reactions. Photocatalytic regeneration is advantageous for the utilization of cheap, abundant, and clean solar energy. Graphitic carbon nitride (g-C 3 N 4) has attracted wide attention due to its non-toxicity, wide range of precursors, suitable band gap, and superior chemical and thermal stability. In this work, mesoporous g-C 3 N 4 (MPCN) was prepared using silica with different size as the template. The preparation process of MPCN was optimized and the effect of the template size on the structure and properties of MPCN were investigated. The results demonstrate that the smaller the template size, the larger the specific surface area of MPCN, and thus the better the photocatalytic performance. After optimization, the catalytic activity of MPCN with 7 nm silica as the template (MPCN-7) was 17.4 mM/(g min) and the NADH yield after 40 min was 70.6 %. MPCN-7 was also modified by 3-aminothiophene-2-carbonitrile (ATCN) and polyvinylpyrrolidone (PVP). Under same conditions, the catalytic activity of ATCN-MPCN, PVP-MPCN, and ATCN/PVP-MPCN was upgraded from 10.8 to 49.5, 16.4, 29.2 mM/(g min), respectively. The final yield of NADH rose from 66.9 % (40 min) to 76.3 % (12 min), 72.8 % (25 min) and 82.0 % (15 min). [Display omitted] • Mesoporous carbon nitride with a series of silica as the template was prepared. • The preparation process including mixing method and mass ratio was optimized. • The template size had great impact on structure and catalytic property of catalyst. • Thiophene and polyvinylpyrrolidone modification was studied. • A high coenzyme regeneration yield of 82 % was achieved after 15 min. [ABSTRACT FROM AUTHOR]

To investigate the polymorphic transformation and crystal morphology changes of ε-CL-20 under different thermal stimuli, isothermal and non-isothermal experiments were conducted using a hot stage microscope and in-situ X-ray powder diffraction. It was found that the ε- and γ- phases coexisted at 120 °C (9.727 wt% γ-CL-20), and the ε→γ phase transformation occurred between 115 and 120 °C and reached completion at 130 °C. The ε-CL-20 expanded isotropically in the temperature range of 25 to 115 °C. About a quarter of the ε-CL-20 transformed after being heated at 120 °C for 12 h, whereas almost all of ε-CL-20 transformed after being heated at 150 °C for 12 h. Under the microscope, the expansion of crystal volume, changes of crystal morphology, and phenomena of decomposition were observed during heating. Molecular dynamics simulation and Rietveld refinement were conducted to verify the experimental results. A solid-solid phase transition mechanism is presented. [Display omitted] • The in-situ PXRD was employed for the phase transition temperature of CL-20. • The morphology changes of CL-20 phase transition were observed. • Both isothermal and non-isothermal experiments were conducted. • MD simulation and Rietveld refinement were used to verify the experiments. • A solid-solid phase transition mechanism is presented. [ABSTRACT FROM AUTHOR]

Abstract: Molecularly-imprinted polymers in the form of microspheres were synthesized using the dispersion polymerization protocol; cyromazine was used as dummy template, while methacrylic acid, ethylene glycol dimethacrylate and acetonitrile (MeCN) were used as functional monomer, cross-linker, and porogen, respectively. When compared with the non-imprinted polymer, the molecularly-imprinted polymers (MIPs) showed outstanding affinity toward melamine in MeCN with a maximum binding concentration (B max) of 53.20nmolmg−1 MIPs, imprinting effect of 4.6, and a dissociation constant (K d) of 90.45μM. After optimization of the molecularly-imprinted solid-phase extraction conditions, a new method was developed to determine the melamine in milk and feed with gas chromatography–mass spectrometry. The performance of this method has been evaluated in the tainted milk and feed in terms of recovery, precision, linearity, the limit of detection (LOD) and limit of quantitation (LOQ). Recovery ranged in samples from 93.1 to 101.3% with intra-day and inter-day relative standard deviation values below 5.34%. The LOD and LOQ of melamine in milk and feed were 0.01μgmL−1 (μgg−1) and 0.05μgmL−1 (μgg−1), respectively. [ABSTRACT FROM AUTHOR]

Tetranitrodimerglycoluril(TNDGU) is a newly developed insensitiveenergetic material. Its solubility in methanol, propanone, ethyl ethanoate,and ethanenitrile between 293.15 K and 313.15 K at atmospheric pressurewas investigated by the gravimetric method. The order of the solubilityof TNDGU is ethanenitrile > ethyl ethanoate ≈ propanone> methanol.The solubility of TNDGU increased with an increase of temperature.The enthalpy of dissolution in each solvent was also calculated accordingto a modified van’t Hoff equation; the values are 25.18 kJ·mol–1for methanol, 41.26 kJ·mol–1for propanone, 34.70 kJ·mol–1for ethyl ethanoate,and 36.33 kJ·mol–1for ethanenitrile, respectively. [ABSTRACT FROM AUTHOR]

[Display omitted] • Intercalation and modification of Ti 3 C 2 T x were studied. • The relation between the structure and the application performance of Ti 3 C 2 T x was illustrated. • NH 4 OH/KCl intercalation brought a higher specific surface area and better intensifying effect. • With the addition of 20 mg PEI-Ti 3 C 2 T x , the enzymatic CO 2 conversion was expedited up to 9.2 times. • PEI-Ti 3 C 2 T x exhibited a good reusability. Ti 3 C 2 T x as a typical MXene material has a multilayer structure similar to accordion, whose interlayer spacing and specific surface area can be regulated by intercalation and modification. In this work, the effects of several kinds of cation-containing intercalators including NH 4 OH, KOH and NH 4 OH/KCl on the structure of Ti 3 C 2 T x and its application performance in enzymatic CO 2 conversion were investigated for the first time. The results show that Ti 3 C 2 T x intercalated with NH 4 OH/KCl had larger layer spacing (25.25 Å) and specific surface area (20.85 m2/g), and better enhancing effect. The initial reaction rate was 0.379 mM/h, which was separately 1.04, 1.42, 1.76 and 5.29 times that of Ti 3 C 2 T x /KOH, Ti 3 C 2 T x /NH 4 OH, Ti 3 C 2 T x and the blank system. Following that, Ti 3 C 2 T x /NH 4 OH/KCl was modified by polyethyleneimine (PEI) and dopamine (DA) and the concentration of modifier was optimized. PEI modified Ti 3 C 2 T x /NH 4 OH/KCl (PEI-Ti 3 C 2 T x) was superior to PEI/DA modified that in the N content, CO 2 adsorption capacity and application performance. With the addition of 20 mg PEI-Ti 3 C 2 T x , the initial reaction rate was 0.658 mM/h, which was 1.74 and 9.2 times that of before modification and the blank system, respectively. PEI-Ti 3 C 2 T x also exhibited a good reusability and the initial reaction rate was 89.4% of the initial value after 10 cycles. [ABSTRACT FROM AUTHOR]

Using reduced nicotinamide adenine dinucleotide (NADH) as cofactor, formate dehydrogenase (FDH) can reversely catalyze CO 2 reduction to formic acid. However, the industrialized application of FDH is fairly limited due to its high cost and stoichiometric cofactor consumption. Enzyme immobilization and cofactor regeneration are vital solutions to these problems. Ascribed to the benefits of utilizing a cheap, environmentally friendly, and renewable energy source, photocatalytic NADH regeneration is naturally sustainable and promising. Nonetheless, the rate-matching and compatibility between photocatalysis and enzyme catalysis have not been well revealed. In this study, polyethyleneimine (PEI) modified hollow fiber membrane (HFM) as the enzyme support was in-situ integrated with a visible-light-driven NADH regeneration system using thiophene-modified macroporous graphitic carbon nitride (ATCN-CN) as the catalyst. First, NADH regeneration conditions were regulated to accommodate enzyme catalysis. Then, the photo-enzyme coupled system (PECS) for the sustainable synthesis of formic acid with triethanolamine (TEOA) or H 2 O as electron donor was constructed, and the influencing factors were investigated. At last, the PECS was compared with other methods as well as a system that used FDH immobilized on silica nanoparticles. The results show that the reaction pH, electron donor, and catalyst concentration have a significant impact on NADH regeneration. For the PECS with TEOA as electron donor, the optimal pH value and photocatalyst concentration for formic acid synthesis are 7.0 and 1.2 mg mL−1, respectively. With the initial addition of 1 mmol L−1 NAD+, a formic acid yield of 35.3% was obtained after 5 h, standing out among the reported values. H 2 O as a green and low-cost electron donor meets the desire for low-cost photocatalysis. Although the production of formic acid after 5 h was lower in the PECS with H 2 O as electron donor than in the TEOA system, it was still 14.6 times that of the immobilized enzyme system without cofactor regeneration, and the yield of formic acid could reach 14.8% and 98.3% with 1 or 0.1 mmol L−1 NAD+, validating that current PECS is feasible to a sustainable and green synthesis of solar fuel from CO 2. [Display omitted] • CO 2 was converted to formic acid by the photo-enzyme coupled system (PECS). • The rate-matching and compatibility of photo and enzyme catalysis was studied. • Yield reached 35.3% after 5 h with 1 mmol L−1 NAD+ and triethanolamine (TEOA). • Yield reached 14.8% and 98.3% after 5 h with 1 or 0.1 mmol L−1 NAD+ without TEOA. [ABSTRACT FROM AUTHOR]

Photonic glasses with infrared gaps can be used as surface coating materials to effectively change the infrared radiation characteristics of substrate. In this research, a photonic glass with an infrared broad gap could be prepared easily in thermostatic water bath by a simple and fast baking protocol. The photonic glass prepared had a broad gap from 4.25 to 4.57 μm, centering at 4.45 μm, which was slightly different from the result of numerical simulation due to the existence of the internal disordered structure. The infrared transmission diagram showed that the infrared transmittance of a substrate covered by the photonic glass can be reduced from 80 % to 25 % at infrared atmosphere window of 3∼5 μm, which proved the ability of the material to regulate and control the infrared electromagnetic wave. In addition, the material can significantly restrain the infrared radiation of the substrate at 60 °C, which was expected to achieve stealth under the infrared detection. [ABSTRACT FROM AUTHOR]

Enzymatic conversion of CO 2 into high-added chemicals is advantageous in mild reaction conditions and high specificity, for which enzyme immobilization and cofactor regeneration are often necessary. Although many efforts have been made, unfortunately, the turnover number (TN) of cofactor does not exceed 100 (~1 usually). Here, an integrated process of formate synthesis from CO 2 catalyzed by hollow fiber membrane immobilized enzyme succeeded with a simple UV/TiO 2 photocatalytic coenzyme regeneration was explored. By optimizing the operating conditions and NADH concentration, TN reached 125 after 4.5 h. This process can be extended to the production of methanol and other similar systems. Unlabelled Image • A high-efficiency and sustainable production of formate from CO 2 is achieved. • A HFM bioreactor is coupled with a photocatalytic cofactor regeneration unit. • Special ventilation and liquid circulation greatly accelerate the reaction. • TN and TOF are obviously higher than most of the reported values. • When NADH concentration is 0.01 mM, TN can reach 125. [ABSTRACT FROM AUTHOR]

A colorimetric sulfur dioxide (SO2) gas sensor based on a core–shell composite was developed. The composite was fabricated with a silicon dioxide core and a mesoporous MCM-41 shell (SiO2@MCM-41), and further loaded with a mixture of zinc chloride (ZnCl2), sodium nitroprusside (SNP) and hexamine as an SO2 indicator. The sensing properties of SiO2@MCM-41 toward SO2 were measured in solid powder, discs and a gas detection tube (GDT), respectively. Each of these sensing configurations showed a distinct color change from pale yellow to red, which indicates good potential for naked-eye detection of SO2. The limit of detection (LOD) is 2 ppm for SiO2@MCM-41 discs, which indicates high sensitivity to SO2. The performance of GDT suggested a linear relationship between the SO2 concentration and the response length of the red portions in a range of 100–1000 ppm. This work shows promising potential of SiO2@MCM-41 as an easy, effective and rapid response sensing material for the in situ detection of SO2. [ABSTRACT FROM AUTHOR]

Istradefylline is a selective adenosine antagonist for A2a receptor, and it is used to treat Parkinson's syndrome and improve dyskinesia in the early stage of Parkinson's disease. Istradefylline aqueous solution were preserved in darkness and light respectively, and it was found that Istradefylline aqueous solution were extremely unstable in light. An impurity of Istradefylline was identified by HPLC and further collected by preparative HPLC. The impurity was characterized by NMR and MS and identified as Z‐Istradefylline, a photo degradation product of Istradefylline. The founding of degradation phenomenon makes the research on the stability of Istradefylline aqueous solution absolutely necessary for the quality control of the drug. [ABSTRACT FROM AUTHOR]

The application of fluorescent method to metal ions detection features high sensitivity, simple operation and real‐time monitoring. A 2,7‐dihydroxynaphthalene‐functionalized dimethyl glycoluril (called clip 1) was synthesized, using a relatively simple method. And it is fully characterized by 1H NMR, 13C NMR, HR‐MS and single crystal X‐ray diffraction. The recognition properties of molecular clip 1 were analyzed systematically toward several metal ions using fluorescence spectroscopy, and it was found that molecular clip 1 is selective and sensitive to Fe3+. At the same time, the clip 1 shows good anti‐interference ability when other metal ions existed. The limit detection of Fe3+ is 3×10−7M. The fluorescence of clip 1 was quenched apparently by Fe3+, which was speculated to be caused by ligand–metal charge transfer mechanism (LMCT). As a new fluorescence probe for Fe3+ ion, it may expanded the application of glycoluril molecular clips. [ABSTRACT FROM AUTHOR]

We report the synthesis of a new acyclic CB[n]-type host (1) that features a central glycoluril trimer capped by triptycene sidewalls. Host 1 has good solubility in water (≈ 3 mM) and does not undergo strong self-association (Ks = 480 M−1). We probed the geometry of the complexes by analyzing the complexation induced changes in the 1H NMR spectra and measured the complexation thermodynamics by isothermal titration calorimetry. The conformation of 1 and its packing in the solid state was revealed by single crystal X-ray diffraction measurements. [ABSTRACT FROM AUTHOR]