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The anticancer therapy strategy mediated by tumor-targeting bacteria needs better visualization tools for imaging and monitoring bacteria in vivo. The probiotic strain Escherichia coli Nissle 1917 (EcN), one of the tumor-targeting bacteria, leads to the potential application for cancer therapy. Here, we report the development and application of a live, EcN-based imageable vehicle for noninvasive in vivo bioluminescence imaging in live mice. Firefly luciferase (Fluc) and luciferin-regenerating enzyme (LRE), an enzyme that contributes to stable bioluminescence, were functionally coexpressed in EcN. The recombinant EcN strain expressing the genomically integrated Fluc-LRE cassette was demonstrated to be a valuable tool for generating robust, continuous, and red-shifted bioluminescence for bacterial tracking in vitro and in vivo, thus providing an optical tumor-targeting system for the in vivo study of bacteria-assisted cancer therapy. Additionally, in vivo imaging of the recombinant EcN strain in the mouse intestinal tract indicated the potential of this strain to be used as a tool in the study of gut.

In this work, the saccharides with different structures and molecular weights were evaluated as a plasticizer for starch-based materials, in which the saccharides from monosaccharides, such as gluc...

N2 electrolysis has been impeded by efficient catalysts for key reactions: cathodic nitrogen reduction reaction (NRR) and anodic oxygen evolution reaction (OER). A bifunctional nickel, iron-nanomes...

Capable of building high-quality, complex parts directly from digital models, selective laser sintering (SLS) additive manufacture (AM) is a core method of agile manufacturing. Polyamide 12 is the most commonly and successfully used polymer powders to date in SLS due to the conforming thermal behaviors of this thermoplastic polymer. State of the art technology produces a substantial amount of un-sintered powders after the manufacturing process. Failure to recycle and reuse these aged powders not only leads to economic losses but also is environmentally unfriendly. This is particularly problematic for powders close to the heat-affected zones that go through severe thermal degradations during the laser sintering processes. Limited procedures exist for systematically reusing such extremely aged powders. This work proposes a new process control method to maximize reusability of aged and extremely aged polyamide 12 powders. Building on a previously untapped interlayer heating, preprocessing, and mixing of powder materials, we show how reclaimed polyamide 12 powders can be consistently reprinted into functional samples, with mechanical properties even superior to current industrial norms. In particular, the proposed method can yield printed samples with 18.04 % higher tensile strength and 55.29 % larger elongation at break using as much as 30 % of extremely aged powders compared to the benchmark sample.

Two new 3D fluorescence metal–organic frameworks, namely [Zn2(p-bdc)4(dfdp)2]n (1) and [Cd2(p-bdc)4(dfdp)4]n (2) (p-H2bdc = 1,4-benzenedicarboxylic acid; dfdp = 4,4′-(2,5-difluoro-1,4-phenylene)dipyridine) have been synthesized under solvothermal conditions and structurally characterized by elemental analysis, infrared spectra, TG, UV–Vis spectra, fluorescence spectra, single crystal and powder X-ray diffraction. Compound 1 shows a 3D framework constructed by infinite [Zn2(p-bdc)4]n layer as nodes and the dfdp ligands as connected linkers. Compound 2 reveals a different structure from compound 1 which can be mainly attributed to different coordination numbers of dfdp linkers. Compared with compound 2, UV–vis spectrum of compound 1 is 25 nm red-shifted. Both compounds show strong solid-state luminescence at about 400 nm. Of particular interest is that the quantum yield of compound 1 is 11.73. Two novel 3D fluorescence metal–organic frameworks [Zn2(p-bdc)4(dfdp)2]n (1) and [Cd2(p-bdc)4(dfdp)4]n (2) have been synthesized and structurally characterized. Compound 1 show strong solid-state purple luminescence with 11.73 quantum yield (QY).

A paramagnetic compound, [Co2(p-bdc)4(dfdp)4)]n (p-bdc = 1,4-benzenedicarboxylic acid, dfdp = 4,4′-(2,5-difluoro-1,4-phenylene)dipyridine), has been solvothermally synthesized and fully characterized. The compound displays a 3D twofold interpenetrating framework with pcu nets with point symbol {412·63}. Thermogravimetric analysis indicates the compound has good thermal stability in solid states. The UV–Vis spectrum demonstrates that the compound has two absorption peaks at 320 and 470 nm. Magnetic investigation shows that the compound exhibits regular Curie behavior.

Environmentally friendly and biodegradable hybrid composites of starch/enteromorpha/nano-clay were developed. Enteromorpha was used as cheaper filler since it is a waste from marine pollution, while nano-clay acted as a reinforcing agent. The microstructures and performance of these composites were investigated by SEM, DMA, XRD, TGA and tensile testing. Enteromorpha has a hollow tubular thallus structure with very weak mechanical properties, so it is not expected to have the ability to reinforce the starch matrix even though they have very a good interface. However, the granulated fine particles of enteromorpha can mix well with the starch matrix and reduce weak points. Furthermore, the delaminated clay by water and ultrasonic treatment reinforced the mechanical properties of the starch-based materials. The results showed that the hybrid composite containing up to 40% enteromorpha reinforced with nano-clay still has similar or even slightly better mechanical properties compared with pure starch-based materials. Since all components are hydrophilic natural materials, the interfaces between them are very good, and the composites are environmentally friendly and biodegradable.

This paper reviews the recent development of starch-based materials, including both fundamental and application researches. In order to overcome the weakness of pure starch-based materials, such as lower mechanical properties found in natural polymers and moisture sensitivity, various blends and composites have been developed in the last two decades. In practical, incorporation of any additives is sensitive in developing fully biodegradable starch-based materials. Furthermore, safety issues will be considered as priority regarding any additives for food packaging applications. Based on these concerns, various natural filler and edible reinforce agents, such as natural fibers, starch or cellulous crystals, and laver, have been used in starch-based materials. So-called self-reinforced techniques, reinforcing starch matrix by modified starch particles, have also been used in developing starch-based composites. During developing starch-based foams the unique function of water, acts as both plasticizer and blow agent for starch-based foam, has been systematically studied. So far, various conventional processing techniques such as extrusion, injection, compression molding, casting and foaming, as well as some new techniques such as reactive extrusion, have been adapted for processing starch-based polymeric materials. Various starch-based products have been developed and commercialized. Keywords: Starch, Biodegradable, Edible, Processing, Phase transitions, Foam

Polyamide 12 is one of the most extensively used semi-crystalline polymer materials to date in selective laser sintering (SLS) additive manufacturing, or SLS 3D printing. In this powder-based direct digital manufacturing process, a substantial amount of expensive materials remains un-sintered, recyclable, and reusable. Recently, understanding the mechanisms of degradation and the reusability of reclaimed polyamide 12 powders has attracted increasing industrial and research interests. However, using reclaimed polyamide 12 powder in SLS results in problems with part surface quality such as undesirable part surface finish with poor textures and numerous un-sintered particles. Limited research is available on the improvement of part surface quality. In particular, results barely exist on improving or modifying the surface quality of parts using extremely aged powders – powders that are held close to the heat-affected zones (HAZs) and suffer from severe degradations during the sintering process. To improve the surface quality and to build interrelations between process parameters and surface quality, we propose a novel approach for SLS with (extremely) aged polyamide 12 powders. By combining material preparation, powder and part characterizations, and SLS with customized post-heating, we obtain parts with improved surface quality (e.g., reduced roughness and porosities, and eliminated un-sintered particles). Particularly, parts 3D-printed using the 30%-30%–40% new-aged-extremely-aged powder mixtures exhibit the smoothest and flattest surface with no unmolten particles and nearly zero porosity.

Ca2+-regulated photoproteins responsible for bioluminescence of a variety of marine organisms are single-chain globular proteins within the inner cavity of which the oxygenated coelenterazine, 2-hydroperoxycoelenterazine, is tightly bound. Alongside with native coelenterazine, photoproteins can also use its synthetic analogues as substrates to produce flash-type bioluminescence. However, information on the effect of modifications of various groups of coelenterazine and amino acid environment of the protein active site on the bioluminescent properties of the corresponding semi-synthetic photoproteins is fragmentary and often controversial. In this paper, we investigated the specific bioluminescence activity, light emission spectra, stopped-flow kinetics and sensitivity to calcium of the semi-synthetic aequorins and obelins activated by novel coelenterazine analogues and the recently reported coelenterazine derivatives. Several semi-synthetic photoproteins activated by the studied coelenterazine analogues displayed sufficient bioluminescence activities accompanied by various changes in the spectral and kinetic properties as well as in calcium sensitivity. The poor activity of certain semi-synthetic photoproteins might be attributed to instability of some coelenterazine analogues in solution and low efficiency of 2-hydroperoxy adduct formation. In most cases, semi-synthetic obelins and aequorins displayed different properties upon being activated by the same coelenterazine analogue. The results indicated that the OH-group at the C-6 phenyl ring of coelenterazine is important for the photoprotein bioluminescence and that the hydrogen-bond network around the substituent in position 6 of the imidazopyrazinone core could be the reason of different bioluminescence activities of aequorin and obelin with certain coelenterazine analogues.

To detect γ-Glutamyl Transpeptidase (GGT) activity in vitro and in vivo, a bioluminescence probe with high sensitivity and specificity was well designed and synthesized. This probe can be recognized by GGT and release strong bioluminescence with its further reaction with luciferase. The performance of this probe was demonstrated in vitro and in cells. Finally, we applied the probe for detection of GGT activity in xenograft model.

The prodrug or caged-luciferin strategy affords an excellent platform for persistent bioluminescence imaging. In the current work, we designed and synthesized ten novel pro-substrates for Renilla luciferase by introducing ester protecting groups of different sizes into the carbonyl group of the free luciferin 1. Taking advantage of intracellular esterases, lipases, and nucleophilic substances, the ester protecting groups were hydrolyzed, resulting in the release of a free luciferin and a bioluminescence signal turn-on. Among the tested pro-substrates, the butyryloxymethyl luciferin 7 exhibited low cytotoxicity and a prolonged luminescence signal both in cellulo and in vivo. Therefore, the butyryloxymethyl luciferin 7 can act as a promising substrate for noninvasive extended imaging in diagnostic and therapeutic fields.

A series of new coelenterazine analogs with varying substituents at the C-6 position of the imidazopyrazinone core have been designed and synthesized for the extension of bioluminescence substrates. Some of them display excellent bioluminescence properties compared to DeepBlueC™ or native coelenterazine with both in vitro and in vivo biological evaluations, thus placing these derivatives among the most ideal substrates for Renilla bioluminescence applications.

A comparison study of the phase transition and structure of waxy cornstarch in DMSO and AMIMCl systems was conducted using a differential scanning calorimeter, an optical microscope, a scanning electron microscope, X-ray diffraction and thermogravimetric analysis. A full disruption and dissolution of starch granules was completed in 10 h at room temperature in pure DMSO, which was faster and more effective than that in ionic liquid 1-allyl-3-methylimidazolium chloride (AMIMCl). When dispersed in DMSO/water and AMIMCl/water at various ratios, respectively, different phase transitions were clearly exhibited, and the appearance and crystal structure of starch granules were significantly damaged with an increase in the concentration. Basing on the study of the decomposition temperature change through TGA measurements, a decreased temperature was observed in both DMSO and AMIMCl system, meaning starch degradation occurred with different levels. The huge temperature change from 357 to 328 °C were found in AMIMCl system, which most likely induced the distinct exothermic phenomenon in the DSC observation due to a significant depolymerization of starch.

High-throughput screening (HTS) of ligand library to find new active molecules for G protein-coupled receptors is still a major interest, as well as an actual challenge. Fluorescence polarization (FP) assay portrays an essential role in HTS; however, in many cases, it was restricted by the absence of FP probes, the narrow measurement window, and low signal-to-noise (S/N) ratio. Herein, based on the modification of our previous probe 1 (QFL), we discovered an FP probe 3 (QGGFL) for α1-adrenergic receptors (α1-ARs), which has satisfactory fluorescence intensity, specific binding ability to receptors, and suitable fluorescence properties that were compatible with the filters in the FP system. Meanwhile, an “ELISA-like” strategy was designed for FP-based HTS assay in which proteins were adhered into a solid phase to improve the measurement window and S/N ratio. With fluorescent antagonist QGGFL and the ELISA strategy, we succeeded in establishing the first competitive binding FP assay for α1-AR antagonists as...

A novel bioluminescence probe for mercury(II) was obtained on the basis of the distinct deprotection reaction of dithioacetal to decanal, so as to display suitable sensitivity and selectivity toward mercury(II) over other ions with bacterial bioluminescence signal. These experimental results indicated such a probe was a novel promising method for mercury(II) bioluminescence imaging in environmental and life sciences ex vivo and in vivo.

Bioluminescence-based techniques, such as bioluminescence imaging, BRET and dual-luciferase reporter assay systems, have been widely used to examine a myriad of biological processes. Coelenterazine (CTZ), a luciferin or light-producing compound found in bioluminescent organisms, has sparked great curiosity and interest in searching for analogues with improved photochemical properties. This review summarizes the current development of coelenterazine analogues, their bioluminescence properties, and the rational design of caged coelenterazine towards biotargets, as well as their applications in bioassays. It should be emphasized that the design of caged luciferins can provide valuable insight into detailed molecular processes in organisms and will be a trend in the development of bioluminescent molecules.

Replacement of the methylene group at the C-8 position with an extended electronic conjugation is a new promising method to develop red-shifted coelenterazine derivatives. In this paper, we have described an oxygen-containing coelenterazine derivative with a significant red-shifted (63 nm) bioluminescence signal maximum relative to coelenterazine 400a (DeepBlueC™, 1 ). In cell imaging, the sulfur-containing coelenterazine derivative displayed a significantly (1.77 ± 0.09; P ≤ 0.01) higher luminescence signal compared to coelenterazine 400a and the oxygen-containing coelenterazine derivative exhibited a slightly (0.74 ± 0.08; P ≤ 0.05) lower luminescence signal. It is beneficial to understand further the underlying mechanisms of bioluminescence.

A novel environment-sensitive probe S2 with turn-on switch for Human Ether-a-go-go-Related Gene (hERG) potassium channel was developed herein. After careful evaluation, this fluorescent probe showed high binding affinity with hERG potassium channel with an IC50 value of 41.65 nM and can be well applied to hERG channel imaging or cellular distribution study for hERG channel blockers. Compared with other imaging techniques, such as immunofluorescence and fluorescent protein-based approaches, this method is convenient and affordable, especially since a washing procedure is not needed. Meanwhile, this environment-sensitive turn-on design strategy may provide a good example for the probe development for these targets that have no reactive or catalytic activity.

Two series of novel coelenterazine analogues (alkynes and triazoles) with imidazopyrazinone C-6 extended substitution have been designed and synthesized successfully for the extension of bioluminescent substrates. After extensive evaluation, some compounds display excellent bioluminescence properties compared with DeepBlueC in cellulo, thus becoming potential molecules for bioluminescence techniques.

The adrenal glands consist of an outer cortex and an inner medulla, and their primary purposes include hormone synthesis and secretion. The adrenal cortex produces a complex array of steroid hormones, whereas the medulla is part of the sympathetic nervous system and produces the catecholamines epinephrine and norepinephrine. In the mouse, GATA binding protein (GATA) 4 and GATA6 transcription factors are coexpressed in several embryonic tissues, including the adrenal cortex. To explore the roles of GATA4 and GATA6 in mouse adrenal development, we conditionally deleted these genes in adrenocortical cells using the Sf1Cre strain of animals. We report here that mice with Sf1Cre-mediated double deletion of Gata4 and Gata6 genes lack identifiable adrenal glands, steroidogenic factor 1-positive cortical cells and steroidogenic gene expression in the adrenal location. The inactivation of the Gata6 gene alone (Sf1Cre;Gata6(flox/flox)) drastically reduced the adrenal size and corticosterone production in the adult animals. Adrenocortical aplasia is expected to result in the demise of the animal within 2 weeks after birth unless glucocorticoids are provided. In accordance, Sf1Cre;Gata4(flox/flox)Gata6(flox/flox) females depend on steroid supplementation to survive after weaning. Surprisingly, Sf1Cre;Gata4(flox/flox)Gata6(flox/flox) males appear to live normal lifespans as vital steroidogenic synthesis shifts to their testes. Our results reveal a requirement for GATA factors in adrenal development and provide a novel tool to characterize the transcriptional network controlling adrenocortical cell fates.

As the most convenient and efficient bioluminescence system, the firefly luciferase/luciferin complex has been widely used in life science research and high-throughput screening (HTS). Nonetheless, the interpretation of firefly luciferase-based assay data is often complicated by the occurrence of “false positives,” in part because firefly luciferase (Fluc) is subject to direct inhibition by HTS compounds that might inadvertently act as inhibitors of its catalytic site. Here we report a series of 2-phenylnaphthalenes as Fluc inhibitors with suitable potency both in vitro and in vivo. Besides, our compound 5 showed significant systemic inhibition in transgenic mice. Enzymatic kinetics study reveals that compound 5 is competitive for substrate aminoluciferin and noncompetitive for the second substrate ATP. Furthermore, compound 5 exhibited good performance as a quenching agent in a dual-luciferase reporter assay. We anticipate that these Fluc inhibitors will contribute to the broader utilization of bioluminescence in life science research while circumventing or at least reducing the number of “false positives”.

Quorum sensing (QS) is a cell-to-cell communication system that regulates gene expression as a result of the production and perception of signal molecules called autoinducers (AIs). AI-2 is a QS autoinducer produced by both Gram-negative and Gram-positive bacteria, in which it regulates intraspecies and interspecies communication. The identification of QS inhibitors is considered a promising strategy for the development of anti-virulence drugs with reduced selective pressure for resistance. Here we describe a high-throughput virtual screening approach to identify AI-2 quorum sensing inhibitors on the basis of Vibrio harveyi LuxPQ crystal structure. Seven potent inhibitors with IC50 values in the micromolar range were selected with no effect or low effect on V. harveyi growth rate.

The first dual bioluminescent and chemiluminescent sensor for detecting highly toxic thiophenols has been developed. Such a probe was designed by using a coelenterazine analogue as the luminophore and dinitrophenyl ether as the recognition moiety. It should be noted that this probe displayed good sensitivity and selectivity toward thiophenols, and has been effectively applied for the quantitative detection of thiophenols in aqueous media and complex biological samples.

Biodegradable elastomer poly[(1,4-butylene terephthalate)-co-(1,4-butylene adipate)] foam was successfully prepared using supercritical CO2. The elastomer foam has closed and uniform cell structure with density about 90 g/L. Narrow size distribution with average cell diameter 32 μm were obtained. The foamed balls show rubbery properties and can recover well (>90%) to their original shape quickly after releasing press stress. Cell growth needs to take place at melting state where the migration and orientation of polymer chains are permanently kept without remained force of springback. Some unique phenomena were observed during foaming the elastomer: post-expansion (about 40%) was obtained after removing the foamed samples from a cylinder mold, which results in forming a ball rather than a cylinder like the mold. This phenomenon was explained by the lower glass transition temperature of the elastomer, in which residual CO2 foam continuously in the room temperature; and “memory” of internal strength. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44354.

Quorum sensing (QS) is a cell-to-cell communication that regulates gene expression and coordinates their behavior in accordance with the cell population density as a result of discerning molecules termed autoinducers (AIs). The processes that QS governed include biofilm formation, bacterial virulence, antibiotic production, competence, conjugation, swarming motility and sporulation. Three main QS AIs are acyl-homoserine lactones, AI-2 and AI peptides. The attractive study of QS leads to an expansive number of QS inhibitors and approaches interfering with QS appearing.This review summarized the recent QS inhibitor-related patents published from 2009 to 2012. The authors have analyzed these patents and have provided an overview of QS inhibitors and their application.The main strategies for QS inhibition related to the patents are disruption of the AI synthase, inactivation of the signal molecule, antagonism of the receptor and promotion of immune response to AI. Some of the natural or synthetic QS inhibitors display excellent activity to manipulate bacterial pathogenicity to offer significant potential in clinical therapy. However, more efforts are needed to be conducted to determine this form of communication to guide the development of QS inhibitors. Overall, QS is a suitable target for antimicrobial therapy and QS inhibitors are likely to lead to a renaissance of anti-virulence drugs without tolerance, which is the ultimate goal expected to achieve in this field.

ObjectiveInnate immunity drives numerous cardiovascular pathologies. Vein bypass grafting procedures are frequently accompanied by low-grade wound contamination. We hypothesized that a peri-graft innate immune challenge, via an outside-in route, augments inflammatory responses, which subsequently drive a component of negative vein graft wall adaptations; moreover, adipose tissue mediates this immune response.MethodsThe inferior vena cava from a donor mouse was implanted into the common carotid artery of a recipient mouse utilizing a validated cuff technique (9-week-old male C57BL/6J mice). Slow-release low-dose (5 μg) lipopolysaccharide (LPS) (n = 9) or vehicle (n = 9) was applied peri-graft; morphologic analysis was completed (day 28). In parallel, vein-grafted mice received peri-graft LPS (n = 12), distant subcutaneous LPS (n = 6), or vehicle (n = 12), then day-1 and -3 harvest of grafts and adipose tissue for cytokines and toll-like receptor (TLR) signaling mRNA expression (qRT-PCR).ResultsAll recipient mice survived, and all vein grafts were patent. Acute low-dose local LPS challenge enhanced vein graft lumen loss (P = .04) and tended to augment intimal hyperplasia (P = .06). The surgical trauma of vein grafting universally upregulated key pro- and anti-inflammatory mediators within the day-1 graft wall, but varied on TLR signaling gene expression. Local and distant LPS accentuated these patterns until at least postoperative day 3. LPS challenge enhanced the inflammatory response in adipose tissue (locally > distantly); local LPS upregulated adipose TLR-4 dramatically.ConclusionsPerivascular and distant inflammatory challenges potentiate the magnitude and duration of inflammatory responses in the early vein graft wall, negatively modulating wall adaptations, and thus, potentially contribute to vein graft failure. Furthermore, surgery activates innate immunity in adipose tissue, which is augmented (regionally > systemically) by LPS. Modulation of these local and distant inflammatory signaling networks stands as a potential strategy to enhance the durability of vascular interventions such as vein grafts.Clinical RelevanceVein graft failure is traditionally considered as a process driven by luminal hemodynamic forces and endothelial injury. We report that the “outside-in” mechanism of local perivascular and distant inflammatory challenges potentiate the magnitude and duration of inflammatory responses in the early vein graft wall, negatively modulating wall adaptations, and thus potentially contribute to vein graft failure. Modulation of these inflammatory signaling networks (eg, extension of antibiotic administration beyond standard wound prophylaxis regimens) stands as a potential strategy to enhance the durability of vascular interventions such as vein grafts.