Latest ArticlesIn recent twenty years, aggregation-induced emission (AIE), due to its excellent application prospect, has aroused widespread interests. The development of novel and easy to make AIE luminogens (AIEgens) is an attractive subject. For this purpose, it is very important to study the structure-property relationship of AIEgens. Because azine derivatives are easy to synthesis and some of them have nice AIE properties, herein, a series of azine derivatives (ADs) were employed as models to study the influence of different functional groups, electronic effects and structures on the AIE properties of azine derivatives. The AIE mechanism were studied by single crystal analysis, density functional theory (DFT) calculations and so on. The results indicated that the o-hydroxyl aryl substituted azine compounds could show good AIE properties. Meanwhile, the AIE properties of o-hydroxyl aryl substituted azine compounds were also influenced by the electronic effects of the aryl groups in the azine compounds. The o-hydroxyl groups could form intramolecular hydrogen bond with imine group, which play key role to restrict the intramolecular rotation of the aryl groups and act as base stone for the AIE process of this kind compounds. The HOMO-LUMO energy gaps of o-hydroxyl substituted azine are smaller than other homologous compounds, which is agree with the proposed AIE mechanism. Finally, thanks to the AIE properties, the o-hydroxy-substituted azines could be used as efficient Al3+ and Cu2+ fluorescent chemosensors in different conditions. In addition, test strips based on AD10 has been prepared, which can conveniently detect Cu2+ in industrial wastewater. This research supplied a way for the design of novel easy to make AIEgens through simple azine derivatives.
Photocatalytic oxidative desulfurization (PODS) over efficient earth-abundant catalysts to obtain clean fuel oil is of great importance for the environmental protection. In this work, a series of Ce-doped MIL-125-NH2 photocatalysts were successfully prepared via a simple in-situ doping method and exhibited superior PODS performance of dibenzothiophene (DBT) under mild reaction conditions. The 1.0 mol% Ce/MIL-125-NH2 catalyst achieved 100% sulfur removal within 22 min at 30 ℃ under visible light illumination, which is mainly attributed to the high surface area and the formation of Ce-Ti-oxo clusters due to electronic coupling. The valence transformation of Ce4+/Ce3+ and Ti4+/Ti3+ redox mediators could not only expose abundant Lewis acid sites, but also promote the separation and transfer of photogenerated charges. In addition, increasing the reaction temperature has been demonstrated to be effective in promoting the PODS performance. Additionally, a thermo-enhanced PODS mechanism was proposed over Ce/MIL-125-NH2, demonstrating the great potential of thermal energy to promote the desulfurization activity.
Mitochondria are critical for tumor growth and metastasis. A number of traditional antitumor drugs have poor water solubility and must penetrate multiple cellular barriers to reach the mitochondria. Because mitochondria have a unique transmembrane potential and an inner membrane with a low permeability, it is difficult for most drugs to enter mitochondria. In recent years, mitochondria-targeted delivery systems that use functional peptides to modify drugs have received increasing attention. Introducing functional peptides can change the original physicochemical properties of drugs and actively target mitochondria. Functional peptide-drug conjugates (PDCs, peptide-drug conjugates) can decompose and release drugs over time or due to certain stimuli in tumors. This preserves the biological activity of the drug while increasing intratumor uptake through the enhanced permeability and retention effect (EPR, the enhanced permeability and retention effect). In this review, we focus on the direction of cancer therapy and review the application of different functional peptides in the mitochondria-targeted tumor treatments reported in recent years.
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.
We report the Lewis acid catalysis of aryldiazonium salts, and their Lewis acidity applications in photogeneration of aryl radicals under additive-, photocatalyst- and transition metal-free conditions. In this visible light-mediated transformation, the Lewis acidic character of aryldiazonium salts enables access to the photoactive charge transfer complex with dichalcogenides. The usefulness and versatility of this new protocol are demonstrated through the chalcogenation of a variety of aryldiazonium salts.
Intracellular pH homeostasis is foundation of maintaining normal physiological functions. More and more evidences show that intracellular pH fluctuations were usually associated with many diseases (such as cancer, epilepsy and neurodegenerative diseases). It is very important to develop in situ real-time determination of pH. In recent years, it has been verified that pH can regulate the isomerization process of spiropyran. Thus, we report a pH fluorescent probe BSL, which is a closed loop spiropyran structure by coupling benzothiazole derivatives with indole salts. We utilizes the process of spiropyran isomerization as the trigger of excited state intramolecular proton transfer (ESIPT) effect, and adjust the process of spiropyran isomerization through pH, and then the molecular transformation from enol to ketone (enol: 525 nm, ketone: 677 nm) through the ESIPT effect. This process achieved accurate measurement of pH. The probe BSL showed sensitive and reversible fluorescence response to pH in vitro. Ultimately, BSL was successfully applied to detect pH fluctuations in cell oxidative stress model.
Point-of-care testing (POCT) technology is highly desirable for clinical diagnosis, healthcare monitoring, food safety inspection, and environment surveillance, because it enables rapid detection anywhere, anytime, and by anyone. Electrochemiluminescence (ECL) has been widely used in chemo-/bio analysis due to its advantages such as high sensitivity, simplicity, rapidity and easy to control, and is now attracting increasing attention for POCT applications. However, to realize the accurate on-site quantitation, it is still challenging to develop portable devices which can precisely collect, analyze, transmit and display the ECL signals. This review will focus on how to develop a portable ECL device by summarizing recent examples and analyzing their key components part by part. Then the possible solutions to the existing challenges in the development and applications of portable ECL devices are summarized and discussed in detail, followed by offering future perspectives. We attempted to provide an appealing viewpoint to inspire interested researchers to comprehend and explore portable ECL sensing systems for practical applications and even commercialization.
Lanthanide coordinated multicolor fluorescent polymeric hydrogels (MFPHs) are quite promising for various applications because of their sharp fluorescence bands and high color purity. However, few attempts have been carried out to locally regulate their fluorescence switching or shape deforming behaviors, but such studies are very useful for patterned materials with disparate functions. Herein, the picolinate moieties that can sensitize Tb3+/Eu3+ luminescence via antenna effect were chemically introduced into interpenetrating double networks to produce a robust kind of lanthanide coordinated MFPHs. Upon varying the doping ratio of Tb3+/Eu3+, fluorescence colors of the obtained hydrogels were continuously regulated from green to orange and then red. Importantly, spatial fluorescence color control within the hydrogel matrix could be facilely realized by controlled diffusion of Tb3+/Eu3+ ions, producing a number of 2D hydrogel objects with local multicolor fluorescent patterns. Furthermore, the differential swelling capacities between the fluorescent patterned and non-fluorescent parts led to interesting 2D-to-3D shape deformation to give well-defined multicolor fluorescent 3D hydrogel configurations. Based on these results, bio-inspired synergistic color/shape changeable actuators were demonstrated. The present study provided a promising strategy to achieve the local fluorescence and shape control within lanthanide coordinated hydrogels, and is expected to be expanded for fabricating useful patterned materials with disparate functions.
Pt-modified amorphous alloy (Pt@PdNiCuP) catalyst exhibits excellent electro-catalytic activity and high experimental durability for hydrogen evolution reaction (HER). However, the physical origin of the catalytically active remains unclear. In this paper, we constructed a distance contribution descriptor (DCD) for the feature engineering of machine learning (ML) potential, and calculated the Gibbs free energies (ΔGH) of 46,000 *H binding sites on the Pt@PdNiCuP surface by ML-accelerated density functional theory (DFT). The relationship between ΔGH and DCD revealed that in the H-Pt distance region of 2.0–2.5 Å where the parabolic tail and disordered scatters coexist, the H-metal bonding configuration is mainly the bridge- or hollow- bonding type. The contribution analysis of DCD indicates that the joint effect of Pt, Pd and Ni atoms determines the catalytical behavior of amorphous alloy, which agrees well with experimental results. By counting atomic percentages in different energy intervals, we obtained the atomic ratio for the best catalytic performance (Pt:Pd:Ni:Cu:P = 0.33:0.17:0.155:0.16:0.185). Projected density of states (PDOS) show that H 1s orbital, Pt 5d orbital, and Pd 4d orbital form a bonding state at −2 eV. These results provide new ideas for designing more active amorphous alloy catalysts.
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.