Latest ArticlesMetal-based catalysts with different site sizes (e.g., metal nanoparticles (NPs) and single atom catalysts (SACs)) demonstrated outstanding catalytic activities in versatile Fenton-like reactions. However, the surface/structural instability is a critical issue, which will result in rapid passivation in Fenton-like reaction and fail in long-term operation. The catalytic stability of the catalysts with different metal sizes considering versatile peroxides (H2O2, peroxymonosulfate (PMS), and peroxodisulfate (PDS)) should be analyzed. In addition, strategies for catalyst regeneration and recyclability improvement are also important to realize the metal-based catalysts for practical applications. In this review, catalytic stability of catalysts with different metal sizes in the backgrounds of versatile peroxides and water matrixes in Fenton-like reactions were first evaluated. Regeneration of metal catalytic sites with different methods were also reviewed. Finally, major challenges and development of methods concerning the stability and regeneration of metal catalytic sites with different sizes were discussed to understand the future researches of metal catalytic sites in Fenton-like reactions.
Derivatives of piperazine, which is one of the most important heterocycles, are often used as linkers to connect active substructures that show promising bioactivities, especially in the field of agrochemicals. From 2000 to 2022, many piperazine-containing compounds were found to exhibit excellent activities against fungi, bacteria, insects, plant viruses, and weeds and have also been used as plant growth regulators. Currently, the development of novel pesticides to prevent the invasion of crop pathogens and ensure the quality and yields of crops is still needed. We herein investigated and summarized the role that piperazine plays in the discovery of pesticides to provide a comprehensive summary of the broad activities of piperazine derivatives in agricultural applications and offer a potential reference for novel pesticide design using piperazine-containing compounds. Moreover, structure–activity relationships (SARs) analyses of bioactive piperazine-containing compounds are also discussed for a deeper understanding.
Exosomes offer ideal biomarkers for liquid biopsies. However, high-efficient capture of exosomes has been proven to be extreme challenging. Here, we report a soluble pH-responsive host-guest-based nanosystem (pH-HGN) for homogeneous isolation of exosomes around physiological pH. The pH-HGN consists of two specifically functionalized modules. First, a pH-responsive module, poly-dimethylaminoethyl methacrylate, provides homogeneous capture circumstances and sharp pH-triggered self-assembly separation in aqueous solution to improve capture efficiency and reduce nonspecific adsorption. Second, a host-guest module, poly-acrylamide azobenzene and β-cyclodextrin linked with exosomes-specific antibody, could act as the "cleavable bridge" to specific capture and subsequent rapid release of captured exosomes through host-guest interaction between β-cyclodextrin and AAAB moieties. The pH-HGN offered high capture efficiencies for exosomes from two different cell lines, which were 90.2% ± 0.28% and 87.0% ± 4.6% for H1299 and MCF-7 cell-derived exosomes, respectively. The purity of isolated exosomes was (1.49 ± 0.71) × 1011 particles/μg, which was 4.1 times higher compared with the gold standard ultracentrifugation (UC) method. Furthermore, the isolated exosomes via the pH-HGN can preserve well integrity and biological activity. The developed pH-HGN was further successfully applied to differentiate lung cancer patients from healthy persons. These findings indicated that pH-HGN is a promising strategy in exosomes-based research and downstream applications.
As a representative of chronic wounds, the long-term high levels of oxidative stress and blood sugar in chronic diabetic wounds lead to serious complications, making them the biggest challenge in the research on wound healing. Many edible natural biomaterials rich in terpenes, phenols, and flavonoids can act as efficient antioxidants. In this study, okra extract was selected as the main component of a wound dressing. The okra extracts obtained via different methods comprehensively maintained the bioactivity of multiple molecules. The robust antioxidant properties of okra significantly reduced intracellular reactive oxygen species production, thereby accelerating the wound healing process. The results showed that okra extracts and their hydrogel dressings increased cell migration, angiogenesis, and re-epithelization of the chronic wound area, considerably promoting wound remodeling in diabetic rats. Therefore, okra-based hydrogels are promising candidates for skin regeneration and wider tissue engineering applications.
High-performance and low-cost gas sensors are highly desirable and involved in industrial production and environmental detection. The combination of highly conductive MXene and metal oxide materials is a promising strategy to further improve the sensing performances. In this study, the hollow SnO2 nanospheres and few-layer MXene are assembled rationally via facile electrostatic synthesis processes, then the SnO2/Ti3C2Tx nanocomposites were obtained. Compared with that based on either pure SnO2 nanoparticles or hollow nanospheres of SnO2, the SnO2/Ti3C2Tx composite-based sensor exhibits much better sensing performances such as higher response (36.979), faster response time (5 s), and much improved selectivity as well as stability (15 days) to 100 ppm C2H5OH at low working temperature (200 ℃). The improved sensing performances are mainly attributed to the large specific surface area and significantly increased oxygen vacancy concentration, which provides a large number of active sites for gas adsorption and surface catalytic reaction. In addition, the heterostructure interfaces between SnO2 hollow spheres and MXene layers are beneficial to gas sensing behaviors due to the synergistic effect.
Thiophenol (PhSH) is an important raw material for organic synthesis, while its high toxicity to organisms makes it an environmental pollutant. Therefore, it is crucial to accurately detect PhSH and explore its metabolic process in the living system. Herein, a near-infrared (NIR) fluorescent probe TEM-FB was developed for sensing PhSH with a turn-on fluorescent signal at 719 nm and a large Stokes shift (198 nm) based on generating the intramolecular charge transfer (ICT) process. TEM-FB shows high specificity and significant sensitivity towards PhSH (detection limit: 10 nmol/L) via the aromatic nucleophilic substitution mechanism. Furthermore, it was successfully applied to image PhSH in multiple cell lines and in zebrafish. Notably, we revealed the oxidative stress process caused by PhSH and demonstrated that the hydrogen peroxide (H2O2) in cells would alleviate the poisonousness from exogenous PhSH for the first time. This work provides a promising bioimaging tool for monitoring PhSH in living systems and visualizing the process of oxidative stress induced by PhSH.
By considering the exceptional properties of supramolecular, noble metals (NM) and magnetic nanoparticles (NPs), we successfully synthesized a novel magnetic, metals and supramolecular composite. Briefly, the Fe3O4@SiO2 core-shell spheres were first modified with gold (Au) and palladium (Pd) NPs and then with mono-6-thio-β-cyclodextrin (SH-β-CD). The synthesized Fe3O4@SiO2-Au-Pd@SH-β-CD nanocomposite shows a good magnetic response (42.3 emu/g). The nanocomposite showed good performance for the reductive degradation of rhodamine B (RhB) and 4-nitrophenol (4-NP). The calculated rate constant (k) values for the reduction of 4-NP and RhB were 0.062± 0.02 s−1 and 0.027± 0.01 s−1, respectively. The high catalytical performance was supposed to be due to the host-guest interaction of β-CD and also due to the NM synergic effect. The nanocomposite structural and chemical morphology was investigated by various spectroscopic techniques. Furthermore, the catalyst was recycled six times and it maintains morphology, chemical nature, and high magnetic behavior, as demonstrated by FTIR and TEM analysis of the recycled catalyst. These results demonstrate a very efficient, cost-effective, and recyclable catalyst in the field of catalysis technology development.
In clinic, the combination of intravenous pembrolizumab (PD-1 monoclonal antibody) with oral Lenvatinib (LEN) exhibited an enhanced synergistic benefit for cancer therapy. However, the clinical outcomes were always limited by the problems of inconsistent pharmacokinetic profiles of two drugs, lower drug accumulation in tumor and obvious side effects during the combination therapy. Here, in situ-forming thermosensitive hydrogels based on PLGA-PEG-PLGA triblock copolymers were prepared for local administration of anti-PD1 and LEN (P&L@Gel) to improve therapeutic efficacy and safety. After peritumoral or surgical resection site injection, the significant increased concentrations of both drugs in tumor were observed with the local sustained release of P&L@Gel. In comparison with the group of intraperitoneal anti-PD1 plus oral LEN (P-ip&L-po), significantly higher tumor inhibition efficiency on CT26 tumor models could be obtained in P&L@Gel group, even at the dose of one-eighth of the former, same tumor-inhibition effects could be achieved. The enhanced antitumor efficacy of P&L@Gel group was probably associated with the 2.2 folds of increased level of CD8+ T cells and the polarization of tumor associated macrophage from M2 to M1 along with the increased drug accumulation. Moreover, compared with the obvious side effects of P-ip&L-po group, no significant changes of PLT, ALT and UA in blood, as well as IL-1α and IL-1β in mice paws were observed between P&L@Gel group and untreated group. These results suggested that local administration of anti-PD1 and LEN with thermosensitive hydrogel could offer a potential strategy for tumors or tumor postoperative adjuvant treatment.
Circularly polarized light (CPL) is an inherently chiral entity and is regarded as one of the possible deterministic signals that led to the evolution of homochirality in earth. Thus, CPL as an external physical field has been widely used in a technique known as absolute asymmetric synthesis, because a product enriched in one enantiomer is formed from racemic precursor molecules without the intervention of a chiral catalyst. In this review, we retrospect the historical research of CPL-induced absolute asymmetric synthesis, including chiral organic molecules, helical polymers, supramolecular assemblies, noble metal nanostructures. However, based on these results, we concluded that the chiral photon-matter interaction is very faint due to the arrangement of molecular bonds giving rise to chiral features, is over a smaller distance than the helical pitch of CPL, leading extremely small enantiomeric excess for product. Therefore, we highlight the recently emerged technology called superchiral field, in which the superchiral far-field and near-field could enhance the dissymmetry of optical field and near-field, respectively. In sum, we hope this review could bring some enlightenment to researchers and further improve the enantioselectivity of CPL-induced absolute asymmetric synthesis.
The threat to public health from bacterial infections has led to an urgent need to develop simpler, faster and more reliable bacterial detection methods. In this work, we developed a universal dual-recognition based sandwich fluorescence resonance energy transfer (FRET) sensor by using specific aptamer-modified quantum dots (Aptamer-QDs) as energy donor and lectin concanavalin A (Con A) modified gold nanoparticles (Con A-AuNPs) as energy acceptor to achieve rapid and sensitive detection of Escherichia coli (E. coli) within 0.5 h. In the presence of the target E. coli, the energy donor of Aptamer-QDs and acceptor of Con A-AuNPs were close to each other, causing changes of FRET signals. Based on the constructed FRET sensor, a linear detection range of from 102 cfu/mL to 2 × 108 cfu/mL with the detection limit of 45 cfu/mL for E. coli was achieved. Furthermore, the FRET sensor was applied to detect E. coli in the milk and orange juice with the detection limit of 300 cfu/mL and 200 cfu/mL, respectively and recovery rate from 83.1% to 112.5%. The strategy holds great promise in pathogenic bacteria detection due to its rapid and sensitivity.
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