Latest ArticlesEfficient oral delivery of drugs treating brain diseases has long been a challenging topic faced by the drug delivery community. Fortunately, polyester nanoparticles offer certain solutions to this problem. This review article firstly describes the main obstacles faced by oral administered brain targeting, including: (1) instability in the gastrointestinal tract; (2) poor penetration of the intestinal mucosa and epithelium; (3) blood clearance; and (4) restriction by the BBB. Then the key factors influencing brain-targeting efficiency of orally administered polyester nanoparticles are also discussed, such as size, shape and surface properties. Finally, recent brain-targeting delivery strategies using oral polyester nanoparticles as carriers and their effects on brain drugs transport are reviewed, and the delivery 'as a whole' strategy of polyester nanoparticles will provide new insight for oral brain-targeting delivery. And by combination of multiple strategies, both the stability and permeability of polyester nanoparticles can be greatly improved for oral brain drug delivery.
The first example of the microfluidic chips (MFCs) consisting of centimeter-level 3D channels with high-density and large-volume fabricated by femtosecond laser micromachining were utilized to develop a time-saving, economical and hazardless flow synthesis process, and its advantages have been proved by in situ formation of aryldiazonium salts and subsequent borylation with bis(pinacolato)diboron. There are several important advantages in our 3D MFC-based flow synthesis technology, including the following: (1) the reaction temperature was altered from ice bath to room temperature; (2) the residence time was reduced by 10 times; (3) the yield was greatly improved, that is, several arylboronates were successfully obtained with higher yield compared to traditional batch process. Therefore, it can be envisioned that a novel, simplified flow synthetic protocol will be developed toward green organic synthesis via MFCs.
Hypoxia is a typical characteristic of hepatocellular carcinoma (HCC), which causes tremendous obstacles to tumor treatments. Current first-line treatment may further deteriorate tumor hypoxia. For example, Lenvatinib, a receptor tyrosine kinase inhibitor (RTKI), suppresses tumor growth via blocking vascular endothelial growth factor (VEGF) signaling, and can also inhibit angiogenesis, thus limiting oxygen supply to tumor sites. Therefore, alleviating tumor microenvironment (TME) hypoxia holds great potential for enhancing the therapeutic effect of RTKI. Here, nanoparticle-stabilized oxygen microcapsules, a stable and biocompatible oxygen-loaded delivery system, are successfully prepared through interfacial polymerization of polydopamine nanoparticles. The microcapsules with a large loading capacity of oxygen in the core show excellent bioavailability and dispersity, which could effectively improve the hypoxic TME when they serve as oxygen delivery vehicles. Synergetic treatments of Lenvatinib and oxygen microcapsules could induce the transition of “cold tumor” in an immune-suppressed state to “hot tumor” in an immune-activated state by improving tumor hypoxic TME and reducing angiogenesis in HCC. It is revealed that combined treatments of oxygen microcapsules and Lenvatinib could polarize tumor-associated macrophages (TAMs) to anti-tumor M1 cells and activate T cell-mediated anti-tumor immune responses. The results suggest that synergetic therapy using oxygen microcapsules and Lenvatinib could alleviate the hypoxic TME and enhance the therapeutic performance of RTKI, demonstrating a promising anti-tumor strategy for enhanced therapy of HCC.
The manganese-catalyzed dehydrogenative coupling between methanol and amines for the synthesis of ureas and polyureas is described. Importantly, catalytic efficiency can be improved by the newly synthesized MACHO ligands. Furthermore, this highly atom-economical protocol demonstrates a broad substrate scope with good functional group tolerance, producing H2 as the sole byproduct. Mechanistic studies disclose that formamide is formed through manganese-catalyzed formylation of amine with methanol. Subsequent dehydrogenation affords a transient isocyanate, which is attacked by another equivalent of amine to provide the final product.
The effective materials and methods for detection and separation of pesticides are urgently needed because most of pesticides show very harmful influence on life and environment. As a new kind of macrocyclic host compound, pillar[n]arenes show very good performance in the detection and separation of pesticides, especially for paraquat (PQ). For the pesticide detection and separation materials, their structures determine performance. Therefore, this review summarizes the recent progress of pillar[n]arenes-based materials for detection and separation of pesticides covering single/multi-pillar[n]arenes, pillar[n]arenes-based polymers, frameworks, composites, nanomaterials, etc. The structure-performance relationships of these materials have been discussed according to the cavity size, the synergistic or collaboration effect, the structure of the polymer or framework, the substrate of the composites and the size of nanomaterials and so on. Based on these, we also look forward to the future and point out the possible way for improving the pesticides detection sensitivity and separation efficiency of this kind of materials.
Anti-infection and neovascularization at the wound site are two vital factors that accelerate diabetic wound healing. However, for a wound healing dressing, the two functions need to work at different sites (inner and outer), giving big challenges for dressing design. In this study, we fabricated a novel sodium alginate/chitosan (SA/CS) Janus hydrogel dressing by the assembly of SA hydrogel loaded with silver nanoparticles (AgNPs) and CS hydrogel impregnated with l-arginine loaded sodium alginate microspheres (ArgMSs) based on electrostatic interactions to combine the two functions. The outer SA-AgNP hydrogel could prevent infection while avoiding the deposition of AgNPs in the wound site, and the inner CS-ArgMS hydrogel on the wound surface could realize the sustained release of l-arginine and promote vascular regeneration. The composition, morphology and swelling/degradation of the SA-AgNP/CS-ArgMS hydrogel were characterized systematically. l-Arginine release behavior has been tested and SA-AgNP/CS-ArgMS hydrogel has been confirmed for excellent biocompatibility. Antibacterial and angiogenesis assays demonstrated the antibacterial and angiogenesis characteristics of the SA-AgNP/CS-ArgMS hydrogel. Finally, in vivo diabetic wound healing assay demonstrated that the SA-AgNP/CS-ArgMS hydrogel could significantly accelerate re-epithelialization, granulation tissue formation, collagen deposition and angiogenesis, thereby resulting in enhanced diabetic wound healing
Aqueous zinc ion batteries (AZIBs) with the merits of low cost, low toxicity, high safety, environmental benignity as well as multi-valence properties as the large-scale energy storage devices demonstrate tremendous application prospect. However, the explorations for the most competitive manganese-based cathode materials of AZIBs have been mainly limited to some known manganese oxides. Herein, we report a new type of cathode material NH4MnPO4·H2O (abbreviated as AMPH) for rechargeable AZIBs synthesized through a simple hydrothermal method. An in-situ electrochemical strategy inducing Mn-defect has been used to unlock the electrochemical activity of AMPH through the initial charge process, which can convert poor electrochemical characteristic of AMPH towards Zn2+ and NH4+ into great electrochemically active cathode for AZIBs. It still delivers a reversible discharge capacity up to 90.0 mAh/g at 0.5 A/g even after 1000th cycles, which indicates a considerable capacity and an impressive cycle stability. Furthermore, this cathode reveals an (de)insertion mechanism of Zn2+ and NH4+ without structural collapse during the charge/discharge process. The work not only supplements a new member for the family of manganese-based compound for AZIBs, but also provides a potential direction for developing novel cathode material for AZIBs by introducing defect chemistry.
Traditional treatment processes cannot completely remove phosphonates in circulating cooling water by one-step method. Herein, we designed peroxymonosulfate/UV irradiation/hydrated zirconium oxide (PMS/UV/HZO) coupling process to enhance the phosphonates removal. In particular, nitrilotris-methylenephosphonic acid (NTMP) removal efficiency by PMS/UV/HZO process was much higher than that of PMS/UV process, UV/HZO process and other processes in comparison experiments. Specifically, almost 97.2% NTMP in water was degraded, and the total phosphorous (TP) reduced from 9.3 mg/L to 0.26 mg/L at pH 7 within 180 min. TP removal efficiency still reached above 90% after 5 cycles adsorption-desorption of HZO. Moreover, Cl¯, NO3¯ and SO42¯ ions all had negligible effect on NTMP removal. During the process, NTMP was first destroyed to form phosphates and other intermediates by the reactive oxygen species (ROS), then phosphates were in situ immobilized via HZO adsorption. Sulfate radical (SO4•−) has been confirmed to be the major ROS in the reaction system by quenching experiment and electron paramagnetic resonance (EPR) characterization. And the excellent selective adsorption capacity of HZO for phosphate produced was attributed to the strong inner-sphere coordination between H2PO4¯/HPO42¯ and Zr-OH on the surface of HZO. These results suggest that PMS/UV/HZO process is a promising technique for enhanced phosphonates decontamination.
Staphylococcus aureus wall teichoic acids (WTAs) are attractive targets for antibacterial vaccine development. In this study, three core glycosylated WTA structure, including α-1,4-GlcNAc, β-1,4-GlcNAc and β-1,3-GlcNAc modified ribitol phosphates containing a linker are chemically synthesized and conjugated with tetanus toxin (TT) carrier protein as vaccine candidates. In vivo immunological studies demonstrate that the synthesized glycosylated WTAs display high immunogenicity and all conjugates provoke strong immune responses and elicit high levels of specific IgG antibodies against the GlcNAc-modified WTA. Furthermore, antibodies elicited by the vaccine candidates remain the capability to recognize S. aureus cells and display significant opsonophagocytic activity to clear S. aureus. This study demonstrates that the core structure of glycosylated WTAs are effective antigens for constructing anti-S. aureus vaccines to prevent and control S. aureus infections.
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