Latest ArticlesFormaldehyde (HCHO) is a common indoor gaseous pollutant, and long-term exposure to it may cause serious damage to the human immune system. Photocatalytic degradation of HCHO is a promising technique. However, most photocatalysts have the disadvantage of rapid recombination of photo-generated electron-hole pairs. In this work, the recombination of photogenerated electron holes was proposed to inhibit through the piezoelectric effect. A two-dimensional (2D) piezoelectric material, 2H-MoS2, was selected to investigate the catalytic performance for HCHO degradation by the synergy of the piezoelectric and photocatalysis properties. The results show that the piezoelectric effect can induce the polarization in 2H-MoS2 and inhibit the recombination of photogenerated electron-hole pairs, thus improving the photogeneration of hydroxyl radicals for HCHO degradation. Therefore, the piezoelectric-photo-catalysis synergistic effect based on density functional theory (DFT) calculation was proposed to elucidate the HCHO degradation performance. This work could provide important guidance for the development of effective catalysts for HCHO degradation and the application of 2D piezoelectric materials.
Deep eutectic solvents (DESs) have drawn considerable attention as a new type of green solvent since they were reported. Subsequent studies have shown that DESs have the potential to be used as "designable" solvents, which means that the precursors of DESs with different structures and properties can be screened to customize DESs for specific functions. Researchers have found that during the sample preparation process involving DESs, the specific properties of some "smart" DESs can be switched by directing external driving forces, leading to a reversible phase transition of the target solution. These "smart" DESs are called switchable deep eutectic solvents (SDESs). The advent of SDES simplifies the sample pretreatment steps, reduces the use of organic solvents, and makes solvents easy to recycle, which matches the concept of green and sustainable chemistry. Compared with the number of previous experimental studies, the reviews and summaries on SDESs are rare. Therefore, this review made a summary of the concept and research progress of SDESs based on some related works in the past decade, including composition and type, characterization, switching mechanism, etc. It is expected to provide a certain reference and guidance for the subsequent in-depth research of SDESs in the analytical sample pretreatment.
Photodynamic therapy (PDT) agents may accumulate in skin and cause severe skin cytotoxicity. We report a pro-guest-based supramolecular strategy to selectively activate PDT in the reactive oxygen specie (ROS) overexpressed microenvironment, which is often existing in tumor and inflammatory tissues. PDT agents methylene blue (MB) and basic blue 17 (BB17) are used as model drugs. When encapsulated by acyclic cucurbit[n]uril (CB[n]), the efficacy of PDT agents is significantly inhibited. By contrast, in the presence of ROS (H2O2) and pro-guest, PDT agents are displaced and reactivated to show a dramatically enhanced PDT efficacy in cells.
The first assembly of a conjugation-ready hexasaccharide from the capsular glycan of C. jejuni. strain BH0142 has been accomplished. The synthesis features the efficient preparation of 6-deoxy-d-ido-heptopyranosyl fluoride donors proceeding from allyl α-d-C-glucopyranoside by a C1-to-C5 switch strategy with radical dehydroxymethylative fluorination as a key step, stereocontrolled construction of 1,2-trans-α-d-ido-heptopyranosidic bonds and of 1,2-cis-α-d-galactopyranosidic linkages. The obtained target oligosaccharide sets a solid foundation for making structurally-defined multivalent glycoconjugate vaccine candidates against C. jejuni. infections.
Heme proteins play various important roles in a variety of physiological and pathological processes. Surfactant assemblies have drawn great attention in fabricating fluorescent sensors to detect and identify proteins. In this study, an acetylpyrene fluorophore containing imidazole HP-1 was synthesized, and it could be well modulated by an anionic surfactant sodium dodecyl sulfate (SDS). The selected ensemble based on HP-1/SDS assemblies exhibited selective fluorescence sensing performance towards the heme proteins, including neuroglobin (Ngb), myoglobin (Mb) and cytochrome c (Cyt c). Besides, phospholipid DMPC vesicles as membrane models were particularly explored the association process between the heme protein Mb and membrane. The present work showed that Mb induced the lysis of DMPC liposomes visualized by transmission electron microscopy and optical microscope.
An unprecedent [4 + 3] cycloaddition of furoketenimines with furocarbenoids has been disclosed for the divergent and efficient synthesis of cycloheptafuran and cycloheptapyrrole scaffolds. Zinc chloride acted as promoters for both the formation of these two transient intermediates from isocyanides and ene-yne-ketones, and the subsequent construction of seven-membered ring. Three rings and five bonds were constructed successively in this three-component one-pot domino reaction.
As for the emerging and cut edge spatially resolved metabolomics, mass spectrometry imaging (MSI) is a powerful tool that can map thousands of metabolites from bio-tissue sections without chemical labels. However, the stability, sensitivity and spatial resolution of MSI are always limited by the performance of its ionization probe. Herein, two types of probes (fine probe (P-100) and large probe (P-200)) were designed and characterized to perform air-flow assisted desorption electrospray ionization (AFA-DESI) MSI analysis for spatially resolved metabolomics. It was determined that the spray introduced by P-100 was homogenous and stable under the spray solvent at a flow rate of 5-10µL/min, while P-200 can endure a high flow rate of up to 10-30µL/min. Moreover, the MSI images were acquired by AFA-DESI-MSI with P-100 from rat brain tissue section and with P-200 from whole-body tissue section of mouse, and these results presented unambiguous tissue structure with the distribution information of numerous metabolites. Furthermore, the spatially resolved metabolomic analysis of tumor tissue was successfully realized to discover the tumor associated biomarkers. As the key parts of AFA-DESI-MSI system, it has been demonstrated that the designed probs have excellent performance for spatially resolved metabolomics, and it will further promote its application in life science, and drug research and development.
Hepatotoxicity is a serious problem faced by clinical drugs, and long-term administration or overdose may lead to liver failure and even death of patients. Therefore, developing a reliable detection method for the early diagnosis and therapy of drug-induced liver injury (DILI) has significant meaning. Near-infrared fluorescence (NIRF) and photoacoustic (PA) dual-modality tomography probes can be used for imaging with high sensitivity and high-resolution of disease-related markers in deep tissues. Here, we developed a novel Cys-activated NIRF and PA dual-modality imaging probe (CDR) for early diagnosis of DILI, for the first time. The organic molecular probe CDR could respond rapidly to Cys, resulting in the absorption peak red-shifted from 560 nm to 725 nm, which also leads to the activation of the PA725 signal and NIRF765 signal. In addition, the new probe CDR could be used for NIRF/PA imaging of exogenous and endogenous Cys level in live cells and mice. More importantly, CDR has also been successfully used for in situ detection of Cys in early DILI mice and evaluate the therapeutic effect of NAC. Therefore, the CDR might become a powerful tool to research the physiological effect of Cys and evaluate the degree of DILI.
With increasing attention to personalized healthcare, miniaturized and easily implementable devices are desired for point-of-care testing (POCT). Herein, hydrophilic patterns were designed on freestanding TiO2 nanotube arrays (TiNTs) as nanoreactors for a naked-eye colorimetric assay. With a high aspect ratio, TiNTs can provide a long observation length combined with a limited volume. Moreover, by combining the photocatalytic property of TiO2 and spatiotemporal controllability of light, hydrophilic nanoreactors were fabricated with minimal volume, and thus the indicator and analyte are limited in a confined void by the hydrophobic surroundings, thus allowing a higher sensitivity for sensing. We believe the proposed sensing platform could provide a promising strategy in developing POCT devices for routine health monitoring.
Nanomedicines have shown great promise in cancer therapy, but are challenged by limited drug loading, safety concerns of drug carriers, and complexity of function integration. Recently, carrier-free nanomedicines produced by supramolecular assembly of small-molecule therapeutic functionalities and their conjugates were proposed to address these issues. These nanomedicines achieve very high drug loading, enhanced tumor accumulation and improved therapeutic efficiency, and avoid carrier-related safety problems. In this review article, the applications of these nanomedicines in chemotherapy, photodynamic therapy, photothermal therapy as well as combination therapies will be reviewed. The concept of nanomedicine design and mechanism of supramolecular assembly will be discussed. Finally, future perspectives of carrier-free supramolecular nanomedicines for cancer therapy will be highlighted.