The large‐dimensional and rigid ceramic bulks fabricated by high‐temperature solid‐phase reaction and sintering have never been considered for possibly entering and circulating within the blood ...vessels for biomedical applications, especially on combating cancer. Here, it is reported for the first time that MAX ceramic biomaterials exhibit unique functionalities for dual‐mode photoacoustic/computed tomography imaging and are highly effective for in vivo photothermal ablation of tumors upon being exfoliated into ultrathin nanosheets within atomic thickness (MXene). As a paradigm, 2D ultrathin tantalum carbide nanosheets (Ta4C3 MXenes) with nanosized lateral sizes are successfully synthesized based on a two‐step liquid exfoliation strategy of MAX phase Ta4AlC3 by combined hydrofluoric acid (HF) etching and probe sonication. The structural, electronic, and surface characteristics of the as‐exfoliated nanosheets are revealed by various characterizations combined with first‐principles calculations via density functional theory. Especially, the superior photothermal‐conversion performance (efficiency η of 44.7%) and in vitro/in vivo photothermal ablation of tumor by biocompatible soybean phospholipid‐modified Ta4C3 nanosheets are systematically revealed and demonstrated. Based on the large family members of MXenes, this work may offer a paradigm that MXenes can achieve the specific biomedical applications (here, theranostic) providing that their compositions and nanostructures are carefully tuned and optimized to meet the strict requirements of biomedicine.
A novel MXene‐based nanotheranostic agent, Ta4C3 nanosheets, is successfully synthesized based on a two‐step liquid exfoliation strategy of the MAX phase Ta4AlC3 by combined HF etching and probe sonication. By the strong X‐ray attenuation capability and high near‐infrared optical absorbance of Ta4C3‐soybean phospholipid nanosheets, largely enhanced in vivo X‐ray computed tomography and photoacoustic dual‐mode imaging of tumors after intravenous administration are achieved.
Membrane fouling is a recognized obstacle for the application of ultrafiltration (UF) for drinking water treatment. In this study, ultraviolet/persulfate (UV/PS) oxidation was employed as a ...pretreatment to control membrane fouling caused by natural organic matter (NOM) in surface water. The effects of UV/PS pretreatment on amounts and characteristics of NOM were investigated in terms of dissolved organic carbon, fluorescent spectrum, molecular weight distribution and hydrophobicity. UF membrane fouling during filtration of raw and pre-oxidized water was compared with transmembrane pressure development, and the fouled membranes were further characterized using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The results indicate that NOM was considerably degraded and partially mineralized (∼58%) by UV/PS pretreatment at a PS dose not exceeding 0.6 mM and a UV irradiation time within 120 min, which was attributed to the generation of sulfate and hydroxyl radicals. The fluorescent compounds in NOM were almost completely degraded (>98%) by the UV/PS pretreatment at a PS dose of 0.4 mM, except for tyrosine-like proteins (∼80%). Moreover, UV/PS pretreatment decreased the ratio of macromolecular compounds and increased the hydrophilic fractions, resulting in reduced NOM adhesion to the membrane. Hence, irreversible fouling by NOM was significantly retarded (∼75%) by the UV/PS pretreatment due to reduction in NOM, and more importantly by preferential degradation of fluorescent, macromolecular and hydrophobic compounds. Fouling control performance was considerably improved at increased PS doses and extended UV irradiation time.
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•UV/PS pre-oxidation was applied to retard UF membrane fouling by NOM.•UV/PS substantially degraded and partially mineralized NOM (<58%) in surface water.•Hydrophobic and fluorescent fractions of NOM were preferentially degraded by UV/PS.•NOM fouling was notably retarded (∼75%) by UV/PS, particularly at higher doses.•Fouling control was due to reduced NOM and improved characteristics.
•The fouling of ceramic hollow fiber membrane were systematically studied.•The interface free energy was calculated by XDLVO theory.•The anti-fouling properties of ceramic and polymer membrane were ...compared.•The ceramic hollow fiber membrane showed excellent anti-fouling performance.
Membrane fouling is a prevalent problem faced by all membrane-based applications, which is affected by membrane features, foulant properties and solution chemistry conditions. Here in this study, we explored the fouling behaviors induced by three typical organic matters (Humic acid (HA), Sodium alginate (SA) and Bovine Serum Albumin (BSA)) during the filtration process of two self-made ceramic hollow fiber MF membranes (denoted as Titania and Alumina, respectively), and compared with that of one commercial PVDF MF membrane. Extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory was employed to investigate the interfacial energy between foulants and different membranes. The results indicated that the anti-fouling ability of the three membranes followed the order: Titania > Alumina > PVDF. Further, it was found that regardless of the membrane features, increase of solution pH improved the interfacial free energy and thus mitigating membrane fouling. The addition of Na+ decreased the fouling tendency of HA and SA, but enhanced the fouling behavior by BSA, while Ca2+ can enhance all the fouling tendency of HA/SA/BSA. Co-existence of different organic matters resulted in a more complex fouling variation, which can not be well described with XDLVO theory. Our research is expected to provide a fundamental reference for MF membrane selection in practical application.
Sulfamethoxazole (SMX), a typical sulfonamide antibiotic, has been widely detected in secondary wastewater effluents and surface waters. In this work we investigated the oxidative degradation of SMX ...by commonly used oxidants of chlorine, ozone and permanganate. Chlorine and ozone were shown to be more effective for the removal of SMX (0.05-5.0mg/L), as compared with permanganate. Higher pH enhanced the oxidation of SMX by ozone and permanganate, but decreased the removal by chlorine. Moreover, the ozonation of SMX was significantly influenced by the presence of humic acid (HA), which exhibited negligible influence on the oxidation by chlorine and permanganate. Fairly lower mineralization of SMX occurred during the oxidation reactions, with the highest dissolved organic carbon (DOC) removal of 13% (for ozone). By using LC-MS/MS, 7, 5 and 5 oxidation products were identified for chlorine, ozone and permanganate and possible transformation pathways were proposed. It was shown that different oxidants shared some common pathways, such as the cleavage of SN bond, the hydroxylation of the benzene ring, etc. On the other hand, each of the oxidants also exhibited exclusive degradation mechanisms, leading to the formation of different transformation products (TPs). This work may provide useful information for the selection of oxidants in water treatment processes.
Gallium and gallium-based alloys, typical types of liquid metals with unique physiochemical properties, are emerging as a next generation of functional materials in versatile biomedical applications. ...However, the exploration of their biomedical performance is currently insufficient, and their intrinsic low oxidative resistance is a key factor blocking their further clinical translation. Herein, we report on the surface engineering of liquid metal-based nanoplatforms by an inorganic silica nanoshell based on a novel but facile sonochemical synthesis for highly efficient, targeted, and near-infrared (NIR)-triggered photothermal tumor hyperthermia in the NIR-II biowindow. The inorganic silica-shell engineering of liquid metal significantly enhances the photothermal performance of the liquid metal core as reflected by enhanced NIR absorption, improved photothermal stability by oxidation protection, and abundant surface chemistry for surface-targeted engineering to achieve enhanced tumor accumulation. Systematic in vitro cell-level evaluation and in vivo tumor xenograft assessment demonstrate that (Arg-Gly-Asp) RGD-targeted and silica-coated nanoscale liquid metal substantially induces phototriggered cancer-cell death and photothermal tumor eradication, accompanied by high in vivo biocompatibility and easy excretion out of the body. This work provides the first paradigm for surface-inorganic engineering of liquid metal-based nanoplatforms for achieving multiple desirable therapeutic performances, especially for combating cancer.
Cancer stem cells (CSCs) are responsible for tumor progression, recurrence, and drug resistance. To identify genetic vulnerabilities of colon cancer, we performed targeted CRISPR dropout screens ...comprising 657 Drugbank targets and 317 epigenetic regulators on two patient-derived colon CSC-enriched spheroids. Next-generation sequencing of pooled genomic DNAs isolated from surviving cells yielded therapeutic candidates. We unraveled 44 essential genes for colon CSC-enriched spheroids propagation, including key cholesterol biosynthetic genes (HMGCR, FDPS, and GGPS1). Cholesterol biosynthesis was induced in colon cancer tissues, especially CSC-enriched spheroids. The genetic and pharmacological inhibition of HMGCR/FDPS impaired self-renewal capacity and tumorigenic potential of the spheroid models in vitro and in vivo. Mechanistically, HMGCR or FDPS depletion impaired cancer stemness characteristics by activating TGF-β signaling, which in turn downregulated expression of inhibitors of differentiation (ID) proteins, key regulators of cancer stemness. Cholesterol and geranylgeranyl diphosphate (GGPP) rescued the growth inhibitory and signaling effect of HMGCR/FDPS blockade, implying a direct role of these metabolites in modulating stemness. Finally, cholesterol biosynthesis inhibitors and 5-FU demonstrated antitumor synergy in colon CSC-enriched spheroids, tumor organoids, and xenografts. Taken together, our study unravels novel genetic vulnerabilities of colon CSC-enriched spheroids and suggests cholesterol biosynthesis as a potential target in conjunction with traditional chemotherapy for colon cancer treatment.
Organic–inorganic hybrid perovskites have created enormous expectations for low-cost and high-performance optoelectronic devices. In prospect, future advancements may derive from reaping novel ...electrical and optical properties beyond pristine perovskites through microscopic structure design and engineering. Herein, we report the successful preparation of two-dimensional inverse-opal perovskite (IOP) photonic films, featuring unique nanostructures and vivid colors. Further compositional and structural managements promise optical property and energy level tunability of the IOP films. They are further functionalized in solar cells, resulting in colorful devices with respectable power conversion efficiency. Such concept has not been previously applied for perovskite-based solar cells, which could open a route for more versatile optoelectronic devices.
In this letter, a novel sext‐band bandpass filter (BPF) using two split‐type multiple‐mode resonators is proposed. The filter is composed of two sets of resonators which are respectively designed to ...realize Filter 1 with two passbands and Filter 2 with quad passbands. Then the two BPFs are combined by parallel coupling feed lines for sext‐band responses, and each of the six centre frequencies in the proposed sext‐band BPF is able to be controlled due to the design freedom. To validate the design and analysis, a prototype filter has been fabricated with six passbands centred at 1.88/2.59/3.48/5.26/5.82/6.75 GHz. The measured result of the fabricated filter agrees well with the simulation, which shows that the proposed structure is a good candidate for sext‐band BPF designs and validates the proposed design flow well.
A novel sext‐band bandpass filter (BPF) using two split‐type multiple‐mode resonators is proposed. To validate the design and analysis, a prototype filter has been fabricated with six passbands centered at 1.88/2.59/3.48/5.26/5.82/6.75 GHz.
Aeromonas hydrophila is an important water-borne pathogen that leads to a great economic loss in aquaculture. Along with the abuse of antibiotics, drug-resistant strains rise rapidly. In addition, ...the biofilms formed by this bacterium limited the antibacterial effect of antibiotics. Bacteriophages have been attracting increasing attention as a potential alternative to antibiotics against bacterial infections. Five phages against pathogenic A. hydrophila, named N21, W3, G65, Y71 and Y81, were isolated. Morphological analysis by transmission electron microscopy revealed that phages N21, W3 and G65 belong to the family Myoviridae, while Y71 and Y81 belong to the Podoviridae. These phages were found to have broad host spectra, short latent periods and normal burst sizes. They were sensitive to high temperature but had a wide adaptability to the pH. In addition, the phages G65 and Y81 showed considerable bacterial killing effect and potential in preventing formation of A. hydrophila biofilm; and the phages G65, W3 and N21 were able to scavenge mature biofilm effectively. Phage treatments applied to the pathogenic A. hydrophila in mice model resulted in a significantly decreased bacterial loads in tissues. Five A. hydrophila phages were isolated with broad host ranges, low latent periods, and wide pH and thermal tolerance. And the phages exhibited varying abilities in controlling A. hydrophila infection. This work presents promising data supporting the future use of phage therapy.
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