Intracellular Polysaccharides of Eurotium cristatum Exhibited Anticolitis Effects in Association with Gut Tryptophan Metabolism.

This study is to investigate the protective effects of Eurotium cristatum intracellular polysaccharides (ECIP) on dextran sodium sulfate (DSS)-induced ulcerative colitis (UC). The oral administration of ECIP could downregulate the disease activity index (DAI) and ameliorate the colonic shortening, immune stress, and damage caused by DSS. In addition, ECIP treatment increased the colonic contents of SCFAs including acetic, propionic, and butyric acids in UC mice. Targeted and untargeted metabolic analysis suggested that ECIP dramatically altered the tryptophan metabolism in the feces of UC mice and promoted the conversion of tryptophan into indole metabolites including indolepyruvate and indole-3-acetic acid (IAA) and indolealdehyde (IAId). Moreover, ECIP observably increased the content of colonic IL-22 and stimulated the relative concentration and relative expression of tight junction molecules in mRNA and proteins levels. Conclusively, consumption of ECIP can improve colon damage and its related effects of UC by promoting the production of IAA and IAId to reinforce intestinal barriers.

DNA-Programmed Lipid Nanoreactors for Synthesis of Carbohydrate Mimetics by Fusion of Aqueous Sub-attoliter Compartments.

Lipid nanoreactors are biomimetic reaction vessels (nanoreactors) that can host aqueous or membrane-associated chemical and enzymatic reactions. Nanoreactors provide ultra-miniaturization from atto- to zeptoliter volumes per reaction vessel with the major challenge of encoding and spatio-temporal control over reactions at the individual nanoreactor or population level, thereby controlling volumes several orders of magnitude below advanced microfluidic devices. We present DNA-programmed lipid nanoreactors (PLNs) functionalized with lipidated oligonucleotides (LiNAs) that allow programming and encoding of nanoreactor interactions by controlled membrane fusion, exemplified for a set of carbohydrate mimetics with mono- to hexasaccharide azide building blocks connected by click-chemistry. Programmed reactions are initiated by fusion of distinct populations of nanoreactors with individually encapsulated building blocks. A focused library of triazole-linked carbohydrate-Cy5 conjugates formed by strain-promoted azide-alkyne cycloadditions demonstrated LiNA-programmed chemistry, including two-step reaction schemes. The PLN method is developed toward a robust platform for synthesis in confined space employing fully programmable nanoreactors, applicable to multistep synthesis for the generation of combinatorial libraries with subsequent analysis of the molecules formed, based on the addressability of the lipid nanoreactors.

Room-temperature watt-level and tunable ∼3 µm lasers in Ho3+/Pr3+ co-doped AlF3-based glass fiber.

A room-temperature watt-level continuous-wave-output power mid-infrared fiber laser operating at $\lambda\sim 3\; \unicode{x00B5}{\rm m}$ is demonstrated using a ${{\rm Ho}^{3 +}}/{{\rm Pr}^{3 +}}$ co-doped ${{\rm AlF} _3}$ based glass fiber as a gain fiber. This fixed-wavelength laser had maximum output power of 1.13 W with a slope efficiency of 10.3% and a long-term operating stability of ${\gt}{40}\;{\min }$ without any additional packaging or active thermal management. A fiber laser with tunability from 2.842 to 2.938 µm showed a maximum output power of 110 mW.

Near-infrared ratiometric self-assembled theranostic nanoprobe: imaging and tracking cancer chemotherapy.

We have developed a novel near-infrared ratiometric fluorescent theranostic nanoprobe. Upon reaction with glutathione, it releases a near-infrared fluorophore and chemotherapy drug. Notably, this nanoprobe can selectively kill HeLa and HepG-2 cancer cells over normal HUVEC cells with negligible side effects. Furthermore, this nanoprobe has been successfully applied to real-time fluorescence tracking and imaging cancer therapy in mice.

Azo-based near-infrared fluorescent theranostic probe for tracking hypoxia-activated cancer chemotherapy in vivo.

A novel azo-based near-infrared fluorescent theranostic probe was synthesized, which is selectively activated under hypoxic conditions, resulting in the release of an active anticancer drug and a near-infrared fluorophore turn-on. Notably, the probe has been applied successfully to real-time visualization of drug delivery in 4T1, HepG2 cells, and mice.

A novel hydrosoluble near-infrared fluorescent probe for specifically monitoring tyrosinase and application in a mouse model.

A novel hydrosoluble near-infrared (NIR) fluorescent probe that could specifically identify tyrosinase has been successfully constructed and applied for imaging of tyrosinase in living cells and zebrafish. Notably, the probe has been successfully applied to the diagnosis of melanoma in a xenogeneic mouse model.

Near-infrared fluorescence probe for hydrogen peroxide detection: design, synthesis, and application in living systems.

Using fluorescent probes to detect endogenous hydrogen peroxide, which is associated with many diseases in the human body, remains an essential technique. Cyanine fluorochromes are a class of dyes that have attracted much attention and are widely used in the synthesis of fluorescent probes. In this article, a novel near-infrared (NIR) fluorescence probe for the detection of hydrogen peroxide was constructed and successfully applied to imaging endogenous hydrogen peroxide in vivo. Notably, probe 1 was designed by connecting 4-(bromomethyl)benzeneboronic acid pinacol ester as the sensing unit to the IR-780 hemicyanine skeleton, which exhibits excellent properties like NIR fluorescence emission over 700 nm. Probe 1 has satisfactory sensitivity to hydrogen peroxide with a low detection limit of 0.14 µM (S/N = 3), attributed to a responding mechanism that leads to the oxidation of phenylboronic acid pinacol ester and thereby releases fluorophore 2. Moreover, probe 1 displays excellent selectivity towards hydrogen peroxide over other substances. Taking advantage of these properties, the probe proved to be cell-permeable. Based on the results of N-acetylcysteine and rotenone together, probe 1 is capable of clearly visualizing endogenously produced hydrogen peroxide in living HepG2 cells and mice. The superior performance of the probe, as a reliable chemical tool, makes it of great potential application for exploring the role played by hydrogen peroxide in biological systems.

Preparation of a Near-Infrared Fluorescent Probe Based on IR-780 for Highly Selective and Sensitive Detection of Bisulfite-Sulfite in Food, Living Cells, and Mice.

A near-infrared fluorescent probe was designed and synthesized for the detection of bisulfite-sulfite in food, living HeLa cells, and mice. The probe is a stable hemicyanine skeleton based on IR-780, which produces a distinct color and fluorescence change before and after reaction with bisulfite and shows excellent analytical performance, such as high sensitivity with a detection limit of 0.37 µM and high selectivity toward bisulfite over other substances. More importantly, the probe determined bisulfite in real food samples (crystal sugar and red wine) with superior recoveries (96.7-106.1%) and has been successfully used to monitor bisulfite in living HeLa cells. Notably, the probe was applied to image bisulfite in BALB/c mice in vivo for the first time. Owing to its biocompatibility, this probe provides a desired method to study the metabolism of bisulfite in cells and shows substantial potential usage in other biosystems and in vivo imaging studies.

Near-Infrared Fluorescent Probes for Hypoxia Detection via Joint Regulated Enzymes: Design, Synthesis, and Application in Living Cells and Mice.

Hypoxia detection is emphasized with attention due to tumor and related diseases diagnosis, which could provide useful methods for exploring the mechanism of hypoxic tumor. Herein, we report two unprecedented hypoxia-sensitive probes that specifically switch-on their near-infrared fluorescence signals in the presence of hypoxia up-regulated enzymes (nitroreductase and cytochrome P450 reductase). The probes were designed by featuring the decomposition of IR-780 coupled to hypoxia activatable p-nitrobenzyl or azo moiety, which exhibit near-infrared fluorescence emission, high sensitivity, selectivity, stable photostability, and low cytotoxicity. Besides, the joint use of two probes could differentiate the 4T1 and HepG2 cells lines through fluorescence signals successfully. More importantly, applied to monitor hypoxia in 4T1 tumor-bearing BALB/c mice, the two probes have ideal biodistribution with passive accumulation and fast clearance, and there is negligible organ damage by hematoxylin and eosin staining analysis. To the best of our knowledge, there is no fluorescent probe for hypoxia detection via joint hypoxia regulated enzymes reported so far. This method may be of great potential use in cancer and other relevant diseases diagnosis.

In Vivo Fluoride Ion Detection and Imaging in Mice Using a Designed Near-Infrared Ratiometric Fluorescent Probe Based on IR-780.

A ratiometric near-infrared fluorescence probe based on IR-780 is developed and applied to fluoride anion (F-) detection in potable water and white flour as well as fluorescence imaging in living cells and mice. The proposed probe not only displays a linear ratiometric (F740/F690 nm) fluorescence response but also possesses near-infrared wavelengths to F- with a detection limit of 0.2 µM. Moreover, the designed probe displays high selectivity toward F-, which makes it feasible for F- detection in potable water and white flour. More importantly, applied to monitor F- in living HepG2 cells and male BALB/c mice, the probe indicates good biocompatibility and low cytotoxicity. However, no study for F- detection has been reported by a ratiometric NIR fluorescent probe so far. We expect that this probe with superior properties has great potential for use in F- detection in biological systems and in vivo studies.

Benzoyl Peroxide Detection in Real Samples and Zebrafish Imaging by a Designed Near-Infrared Fluorescent Probe.

A novel near-infrared fluorescence off-on probe, (E)-3,3-dimethyl-1-propyl-2-(2-(6-(2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzyloxy)-2,3-dihydro-1H-xanthen-4-yl)vinyl)-3H-indolium (1), is developed and applied to benzoyl peroxide (BPO) detection in real samples and fluorescence imaging in living cells and zebrafish. When arylboronate as the recognition unit is connected to a stable hemicyanine skeleton, the probe is readily prepared, which exhibits superior analytical performance, such as near-infrared fluorescence emission over 700 nm and high sensitivity with a low detection limit of 47 nM. Upon reaction with BPO, phenylboronic acid pinacol ester is oxidized, followed by hydrolysis and 1,4-elimination of o-quinone methide to release fluorophore. In addtion, the probe displays high selectivity toward BPO over other common substances, which makes it of great potential use in quantitative and simple detection of BPO in wheat flour and antimicrobial agent. More importantly, the probe has been successfully demonstrated for monitoring BPO in living HeLa cells and zebrafish. The probe with superior properties could be of great potential use in other biosystems and in vivo studies.