Latest ArticlesBiomacromolecules are attractive in biomedical applications as therapeutic agents and potential drug carriers due to their natural active components, good biocompatibility, and high targeting. However, their large relative molecular weight, complex structure, susceptibility to degradation, and poor stability limit their usefulness. Nanotechnology can address these issues by improving the therapeutic value, bioavailability, permeability, and absorption of biomacromolecules while regulating their retention time in the body. Especially, compelling evidence has been reported that supercritical fluid (SCF) technology has emerged as an alternative that maintains the integrity of biomacromolecules and reduces environmental contamination. In this review, we highlight a set of unique nanosizing strategies based on SCF technology for biomacromolecular nanomedicine, and extensively discuss their characteristics and mechanisms. In particular, the protein-based, nucleic acid-based, and polysaccharide-based nanomedicine preparations via SCF technology and their biomedical applications are summarized, and the potential for industrial production of biomacromolecular drugs is also considered. We further provide perspectives on the opportunities and challenges in this excellent field of biomacromolecular drugs nanotechnology.
Due to the advantages of renewable, low pollution and wide distribution of biomass resources, it is selected as the electrode material for supercapacitors. For carbon-based electrode materials, specific surface area and pore structure have a great influence. Exploring and summarizing the influence of activation on pore structure will greatly broaden this field. Based on the activation mechanism of activator, this paper summarizes the latest progress of biomass activation applied to supercapacitors, including traditional physical and chemical activation methods and non-traditional methods such as biological activation method, self-activation method, template assisted activation method and green activator activation. Finally, the challenges, strategies and prospects for the future development of biomass-derived carbon material activation are pointed out. In summary, this review will help researchers choose appropriate strategies to design biomass-derived carbon electrode materials for supercapacitors, thereby promoting the application of biomass materials.
Constructing composited electrode material is considered to be an efficient strategy to improve their electrochemical performance. It can accelerate the charge transfer speed of ions and enhance the conductivity of electrode. Meanwhile, the formation of the hybrid structure can largely avoid the aggregation of two dimensional materials and increase the electrochemical active area of the electrode. In this work, we synthesize NiMoSSe electrode materials on nickel foam by a facile hydrothermal avenue. The prepared composite shows a specific capacitance of 1035 C/g at 1 A/g due to the synergistic effect between MoS2 and MoSe2 phases. In addition, the devices are assembled with NiMoSSe samples, which offers an energy density of 82.71 Wh/kg at a power density of 2700 W/kg.
Molecular ferroelectrics have attracted much attention because of their excellent piezoelectricity, mechanical workability, and second harmonic effect. Here, we successfully prepared two molecular ferroelectrics 1,5–3.2.2-HdabcniX (X = ClO4−, 1; ReO4−, 2) by reactions of a quasi-spherical amine 1,5-diazabicycle[3.2.2]nonane (1.5–3.2.2-dabcn) with HX aqueous solution. Compounds 1 and 2 undergo high-temperature phase transitions at 381 K (1) and 396 K (2). Before and after the phase transition, they crystallize in the polar point group mm2, and the centrosymmetric point groups mmm and 4/mmm, respectively. According to Aizu rules, these two compounds experience mmmFmm2 and 4/mmmFmm2 type ferroelectric phase transitions, respectively. The ferroelectricity of both compounds is well expressed in their polycrystalline film at room temperature with low coercive voltages of 13 V for 1 and 25 V for 2. Using piezoelectric force microscopy (PFM), the 180° anti-parallel ferroelectric domains and the reversible polarization switching can be clearly observed in 1 and 2. This high-temperature molecular ferroelectric material has great application potential in flexible materials, biomechanics, intelligent wearables and other fields.
The physicochemical properties of transition metal dichalcogenides (TMDs) are highly related to their structures and usually stable in air. However, under certain conditions they could be transformed into different structures due to oxidation. Considering this, various materials with fascinating structures have been explored by oxidation strategies, which possess novel properties and great potential in various applications such as solar batteries, hydrogen evolution reaction (HER) catalysts, and field effect transistors (FET). In this review, we systematically summarize the atomic structures of TMD oxidized variants and the corresponding fabrication approaches. Utilizing various characterization methods, the chemical components of TMD oxidized variants are illustrated. Furthermore, we expound the promising applications of the oxidized variants. This review is expected to provide a new insight for preparing precise materials at the atomic level through corresponding oxidation strategies.
Hybrid metal-organic framework (MOF) derivatives play a significant role in the novel catalyst development in energy conversion reactions. Here, we demonstrated the low-temperature fully fluorinated zeolitic imidazole framework (ZIF) coupled with a three-dimensional open framework Prussian blue analog (PBA) with combined advantages for electrocatalytic oxygen evolution reaction (OER) in water splitting reaction. The spectroscopic analysis and the electrochemical studies revealed the combined advantages of efficient electronic effect and active site synergism. Because of good conductivity improvement by N-doped carbon derived from ZIF and the high electrochemical surface area and active site exposure from PBA derivatives, good catalytic performance was obtained on the optimal catalyst of CoNi ZIF/CoFe-PBA-F-300, which required a low overpotential of 250 mV to reach 10 mA/cm2 loaded on the glassy carbon electrode, with Tafel slope of 47.4 mV/dec, and very high dynamic and steady stability. In addition, the multi-component with the mixed structure from highly polar metal fluorides promoted the easy formation of the active phase as revealed by the post-sample analysis. The current results showed a novel composite catalyst materials development from the hybrid MOF derivatives, which would be promising in the electrolysis of water oxidation reactions and energy-relevant catalysis reactions.
Molecular dielectric switches constitute a type of intelligent materials that are highly coveted for their distinctive advantages of switchable dielectric responses, lightweight, and mechanical flexibility. Two-dimensional (2D) hybrid perovskites have demonstrated excellent promise for assembling dielectric switches, in which the dynamic motions of organic moieties afford driving force to trigger switchable dielectric phase transition. Here, we successfully assembled a new lead-free hybrid double perovskite, (CHA)4CuBiBr8 (1, CHA = cyclohexylammonium), adopting a typical 2D structural motif, which shows dielectric anisotropy and bistable behaviors during the reversible phase transition near Tc = 378 K (the Curie temperature). That is, its dielectric constants could be switched and tuned between high-dielectric and low-dielectric states. Structure analyses reveal that the ordered-disordered transformation of the organic CHA+ moiety and distortion of inorganic framework account for its phase transition. This result will stimulate further exploration of molecular dielectric switches in this 2D environmentally friendly family.
The exploration of advanced materials through rational structure/phase design is the key to develop high-performance lithium-ion capacitors (LICs). However, high complexity of material preparation and difficulty in quantity production largely hinder the further development. Herein, Cu5FeS4-x/C (CFS@C) heterojunction with rich sulfur vacancies has successfully achieved from natural bornite, presenting low cost-effective and bulk-production prospect. Density functional theory (DFT) calculations indicate that rich vacancies in bulk phase can decrease band gap of bornite and thus improve its intrinsic electron conductivity, as well as the heterojunction spontaneously evokes a built-in electric field between its interfacial region, largely reducing the migration barrier from 1.27 eV to 0.75 eV. Benefited from these merits, the CFS@C electrodes deliver outperformed lithium storage performance, e.g., high reversible capacity (822.4 mAh/g at 0.1 A/g), excellent cycling stability (up to 820 cycles at 2 A/g and 540 cycles at 5 A/g with respective capacity retention of over or nearly 100%). With CFS@C as anode and porous carbon nanosheets (PCS) as cathode, the assembled CFS@C//PCS LIC full cells exhibit high energy/power density characteristics of 139.2 Wh/kg at 2500 W/kg. This work is expected to offer significant insights into structure modifications/devising toward natural minerals for advanced energy-storage systems.
In recent years, the emerging two−dimensional material−MXenes has attracted widespread attention in the field of photocatalysis due to its high conductivity, suitable Fermi level, tunable elemental composition, and excellent photoelectric properties. The zero−dimensional quantum dots (MQDs) derived from 2D MXenes not only inherit the characteristics of MXenes but also exhibit better performance due to the quantum size effect. Based on the above excellent physical and chemical properties, MQDs are often used as co−catalysts of photocatalysts, and show excellent co−catalytic properties. At the same time, compared with other cocatalysts (precious metals, metal oxides, metal sulfides), it has the advantages of low cost and high conductivity. Therefore, understanding the status of MQDs in the field of photocatalysis is crucial for their further development. In this review, we summarized the synthesis and modification methods of MQDs in recent years, as well as their photocatalytic applications in H2 production, CO2 reduction, N2 fixation, pollutant degradation, and other aspects. In addition, the challenges and prospects faced by MQDs are also proposed, providing theoretical guidance for the further development of MQD−based photocatalysts.
Immunosuppressive microenvironments present critical problems in clinical chemotherapy. To regulate the tumor immune microenvironment for enhancing antitumor effect, a combination of immune checkpoint inhibitors (ICIs) with chemotherapeutics has been applied clinically. In this study, miriplatin (MiPt), the lipidic derivative of 5-fluorouracil (Fu-OA), as well as the programmed death ligand 1 (PD-L1) target siRNA (siPD-L1) were integrated into Lip-Pt/Fu@siPD-L1 nanoparticles (NPs) for chemo-immunotherapy. In vitro results showed that Lip-Pt/Fu@siPD-L1 NPs could exhibit effective siRNA gene silencing and promote the phagocytosis of tumor cells by macrophages. Furthermore, in vivo results revealed that Lip-Pt/Fu@siPD-L1 NPs showed significantly higher anti-tumor efficiency than that of the physical mixing of MiPt, 5-fluorouracil, and Lip@siPD-L1 NPs (delivery of siPD-L1 by liposomes). The best anti-tumor efficiency of Lip-Pt/Fu@siPD-L1 NPs resulted from the synergistic immunotherapeutic effects of MiPt and siPD-L1 based on the inhibition of CD47 expression and the downregulation of PD-L1 in tumor cells, which elicited a robust anti-tumor immune response through the activation of macrophage phagocytosis and immune checkpoint inhibition. The Lip-Pt/Fu@siPD-L1 NPs provide a potential strategy for tumor chemo-immunotherapy.