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Metal selenides have aroused significant attention in the realm of efficient ion storage attributed to their exceptional chemical and physical properties, whereas their utilization in sodium-ion batteries (SIBs) is hindered by poor rate performance and cycle stability that originated from their substantial volume expansion throughout Na+ insertion/extraction procedures. This work proposes a productive approach to preserve the structure of the FeSe2 anode via in situ coating nitrogen-doped carbon (NC). The powerful interfacial interaction between FeSe2 micro-nanorods and NC facilitates fast Na+/e− transport kinetics and ensures excellent structural stability of FeSe2@NC. Consequently, FeSe2@NC exhibits a capacity of 379.2 mA h g−1 at a high current density of 10 A g−1 and up to 100% reversible capacity over 1000 cycles at 5 A g−1. Furthermore, the invertible Na+ storage mechanism of FeSe2@NC is investigated by ex situ methods. When FeSe2@NC is used as the anode and Na3V2(PO4)2F3@reduced graphene oxide is used as the cathode to assemble a full battery, it also exhibits a capacity of 167.2 mA h g−1 even after 1000 cycles at 1 A g−1. These exemplary results underscore the potential application value of FeSe2@NC in fast-charging SIBs. [ABSTRACT FROM AUTHOR]

Hierarchical nanosheet-based MoS2–NiS nanotubes coated with N-doped carbon (MNS-HNT@NC) composites were fabricated using a template-assisted hydrothermal and post-sulfidation strategy. The composite, with a tube-like structure, is mainly constructed by ultrathin MoS2–NiS nanosheets. Such hierarchical nanosheet-based nanotubes possess high surface-to-volume ratios, which can release mechanical stress during Na ion insertion/extraction and shorten the pathways for Na ion/electron transport. Furthermore, the internal void space in the nanotube can effectively accommodate the large volume change of the electrode, thereby alleviating structural collapse of the electrode. On the other hand, abundant lattice defects and the internal electric field induced by the heterostructure of MoS2 and NiS boost the Na ion intercalation kinetics. In addition, the MoS2 and NiS nanocrystals uniformly dispersed in the composite can act as mutual spacers, thereby avoiding aggregation during cycling. The MNS-HNT further coated with N-doped carbon can reduce contact resistance and restrict the large volume change, preventing electrode pulverization. Benefiting from these advantages and using an ether-based electrolyte, MNS-HNT@NC, as anode for SIBs, delivers a considerable specific capacity (707 mA h g−1 at 0.1 A g−1), high initial coulombic efficiency of 94%, stable long-term cycling stability (391 mA h g−1 maintained after 700 cycles at 2 A g−1) and superior rate performance (342 mA h g−1 at 10 A g−1). [ABSTRACT FROM AUTHOR]

Developing economical, efficient and stable bifunctional catalysts for hydrogen production from seawater is of great significance for hydrogen utilization. Herein, sulfur doped iron oxide nanosheet arrays supported on nickel foam (FeOx–Ni3S2@NF) are prepared by a one-pot solvothermal reaction. Owing to the high intrinsic activity of FeOx–Ni3S2, the large catalytic specific surface area of nanosheet arrays and the fast charge transportation capability achieved by the self-supporting configuration, the FeOx–Ni3S2@NF electrode delivers excellent catalytic performance in alkaline simulated seawater (1 M KOH + 0.5 M NaCl). Impressively, a low overpotential of 120 mV at 50 mA cm−2 with a Tafel slope of 57 mV dec−1 for the hydrogen evolution reaction and an overpotential of 470 mV at 200 mA cm−2 with a Tafel slope of 62 mV dec−1 for the oxygen evolution reaction are achieved. More importantly, the voltage is only 1.5 V at 50 mA cm−2 for continuous overall water splitting for 100 h at 200 mA cm−2 with negligible decay in alkaline simulated seawater with almost 100% Faraday efficiency. This work provides a simple and universal strategy to prepare highly efficient bifunctional catalytic materials, promoting the development of Earth-abundant materials to catalyse seawater splitting to produce high-purity hydrogen. [ABSTRACT FROM AUTHOR]

We have prepared a type of magnetic mesoporous nanomaterial with aggregation-induced emission properties (Fe3O4@mSiO2@TPA@BA, hence abbr. FSTB) to detect and remove cyanide ions (CN−) under magnetic conditions. FSTB has a large specific surface area and improved fluorescence performance to identify CN−, and its superparamagnetic behavior plays an important role in removing CN−. The magnetic sensor FSTB shows excellent selectivity and anti-interference for the detection of CN− in aqueous solutions. It is obvious from the equation LOD = 3δ/S that the limit of detection (LOD) of FSTB for CN− is significantly lower than the permissible level of CN− in drinkable water recommended by the World Health Organization. Therefore, the magnetic sensor FSTB has a wide range of applications for detecting and removing harmful CN−. [ABSTRACT FROM AUTHOR]

Much attention has been paid to the fabrication of two-dimensional (2D) nanomaterials as therapeutics for nanomedicine in recent years owing to their special physicochemical characteristics. These fascinating physicochemical properties alongside their diverse biomedical applications drive us to give a review of the present endeavors of interest in these 2D nanomaterials. In this review, the up-to-date research advances of the preparation, biocompatibility and biodegradation behaviors of 2D nanomaterials including transition-metal dichalcogenides (TMDs), transition metal oxides (TMOs), black phosphorus (BP) nanosheets, metal–organic frameworks (MOFs), 2D boron (B), boron nitride (BN), layered double hydroxides (LDHs), 2D nanoscale metals, and other kinds of 2D nanomaterials are introduced. The in vitro and in vivo bio-compatibility, including their degradation assessments from the aspects of a redox reaction, enzymes, pH, and the cell environment, etc., of the above categories of 2D nanomaterials are discussed in detail. Finally, the prospects and challenges of the development of 2D nanomaterials aiming for biomedical applications are summarized. [ABSTRACT FROM AUTHOR]

CO2 microbubbles (MBs) were explored as smart agent in suppressing tumors. CO2 MBs can be massively produced from the decomposition of an effervescent disintegrant in water. However, the explosive decomposing of the effervescent disintegrant in water will extremely limit its therapeutic applications. The short retention duration of CO2 MBs in blood and the tiny quality of MBs that can leak into tumor sites also severely decrease the tumor therapy efficiency. In this research, a multifunctional poly(lactic-co-glycolic acid) (PLGA)-based solid implant was facilely in situ constructed within tumors based on the liquid–solid phase transition of hydrophobic PLGA/effervescent disintegrant/doxorubicin (DOX) (denoted as PED) oleosol, to effectively control the decomposition of the effervescent disintegrant and increase the accumulation of MBs in the tumor site. The formed PED implant could simultaneously function as a high intensity focused ultrasound (HIFU) enhancement agent and a drug delivery platform featured with HIFU-responsive DOX and spontaneous MBs releasing characteristics. Without HIFU treatment, the hydrophobic PLGA will prevent the contacting of effervescent disintegrant or DOX with water. Under HIFU treatment, water could easily diffuse into the PED implant and thus DOX release, effervescent disintegrant decomposition and CO2 release will be switched on. These CO2 MBs can oscillate with the external focused ultrasound and enhance the mechanical and cavitation effect of focused ultrasound, resulting in an enhanced tumor HIFU ablation towards a VX2 tumor-bearing New Zealand White rabbit. Importantly, it is difficult for effervescent disintegrant and DOX to enter the bloodstream in quantity, therefore, the utilization of CO2 MBs and DOX can be increased and the in vivo biosafety of the implant can be guaranteed. The developed PED implant features easy fabrication, low cost, and excellent in vivo hemo-/histo-compatibility, and holds promising potential for future clinical translation for localized tumor therapy. [ABSTRACT FROM AUTHOR]

Exploring a plasmid DNA (pDNA)/small interfering RNA (siRNA) delivery vector with excellent biocompatibility and high gene transfection efficiency still remains a great challenge. In this research, generation 5 (G5) dendrimer-entrapped gold nanoparticles (Au DENPs) partially modified with polyethylene glycol monomethyl ether (mPEG) were designed as non-viral pDNA/siRNA delivery vectors. The pDNA that can encode luciferase (Luc) or enhanced green fluorescent protein (EGFP) and the Bcl-2 siRNA that can knockdown the expression of the Bcl-2 protein were successfully packaged by the partially PEGylated Au DENPs and effectively delivered into HeLa cells. The length of the surface conjugated mPEG chains and the composition of the entrapped Au NPs were systematically altered to explore their influences on the structure, cytotoxicity, and pDNA or siRNA delivery efficiency. We show that the modified mPEG and entrapped Au NPs can significantly improve the encoding of Luc and EGFP or silence the Bcl-2 protein expression, and the {(Au0)50-G5.NH2-mPEG2K} DENPs display the best DNA or siRNA delivery efficiency among all the designed partially PEGylated Au DENPs. The Luc transfection efficiency of the {(Au0)50-G5.NH2-mPEG2K} was about 292 times higher than that of the G5.NH2 dendrimers at an N/P ratio of 5 : 1, and the Bcl-2 protein was silenced to 15% using the {(Au0)50-G5.NH2-mPEG2K} as a vector relative to the expression level transfected using the G5.NH2 dendrimers (100%). With enhanced pDNA/siRNA transfection efficiency and less cytotoxicity, the PEGylated Au DENPs may hold great promise to be used in pDNA and siRNA delivery applications. [ABSTRACT FROM AUTHOR]

We report here a facile approach to assembling low generation poly(amidoamine) (PAMAM) dendrimer-stabilized gold nanoparticles (Au DSNPs) onto electrospun polymer nanofibrous mats for catalytic applications. In this study, Au DSNPs formed using amine-terminated generation 2 PAMAM dendrimers as stabilizers were assembled onto electrospun polyacrylic acid (PAA)/polyvinyl alcohol (PVA) nanofibrous mats either through electrostatic interactions or through the covalent 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC) coupling reaction. The assembly of Au DSNPs with a mean diameter of 5.4 nm onto the electrospun nanofibrous mats was characterized via different techniques. The catalytic activity of the Au DSNP-assembled nanofibrous mats was evaluated by the transformation of 4-nitrophenol to 4-aminophenol. We show that both approaches enable the efficient assembly of Au DSNPs onto nanofiber surfaces and the as prepared Au DSNP-containing nanofibers formed via both approaches have excellent catalytic activity and reusability. However, the Au DSNP-assembled nanofibers via electrostatic physical interactions display a much higher catalytic activity than those formed via the chemical assembly approach. The facile dendrimer-mediated assembly approach to modifying electrospun nanofibers may be used to fabricate other composite nanofiber systems for applications in catalysis, sensing, and biomedical sciences. [ABSTRACT FROM AUTHOR]

Endoscopic tattooing is a localization technique that is particularly important for identifying gastrointestinal lesions for follow-up and subsequent treatment. However, the dyes currently used for endoscopic tattooing have a short tattooing time, high cost, and many side effects. Herein, we designed and prepared polydopamine (PDA) nanoparticles modified with polyvinylpyrrolidone (PVP) for endoscopic tattooing using a physical encapsulation method. PDA has good stability and high adhesion properties, and its stability was further enhanced after PVP modification. In vitro and in vivo tests demonstrated that PDA/PVP has good biosafety. Endoscopic tattooing with PDA/PVP in a porcine model showed that the dye could be stabilized in the digestive tract for at least 60 days. Furthermore, our research results demonstrated that PDA/PVP has excellent reactive oxygen species (ROS) and reactive nitrogen species (RNS) scavenging ability and can promote wound healing. Overall, the strategy proposed herein will lead to the use of an innovative dye for endoscopic tattooing of gastrointestinal lesions.

Developing economical, efficient and stable bifunctional catalysts for hydrogen production from seawater is of great significance for hydrogen utilization. Herein, sulfur doped iron oxide nanosheet arrays supported on nickel foam (FeO x -Ni 3 S 2 @NF) are prepared by a one-pot solvothermal reaction. Owing to the high intrinsic activity of FeO x -Ni 3 S 2 , the large catalytic specific surface area of nanosheet arrays and the fast charge transportation capability achieved by the self-supporting configuration, the FeO x -Ni 3 S 2 @NF electrode delivers excellent catalytic performance in alkaline simulated seawater (1 M KOH + 0.5 M NaCl). Impressively, a low overpotential of 120 mV at 50 mA cm -2 with a Tafel slope of 57 mV dec -1 for the hydrogen evolution reaction and an overpotential of 470 mV at 200 mA cm -2 with a Tafel slope of 62 mV dec -1 for the oxygen evolution reaction are achieved. More importantly, the voltage is only 1.5 V at 50 mA cm -2 for continuous overall water splitting for 100 h at 200 mA cm -2 with negligible decay in alkaline simulated seawater with almost 100% Faraday efficiency. This work provides a simple and universal strategy to prepare highly efficient bifunctional catalytic materials, promoting the development of Earth-abundant materials to catalyse seawater splitting to produce high-purity hydrogen.

We have prepared a type of magnetic mesoporous nanomaterial with aggregation-induced emission properties (Fe 3 O 4 @mSiO 2 @TPA@BA, hence abbr. FSTB) to detect and remove cyanide ions (CN - ) under magnetic conditions. FSTB has a large specific surface area and improved fluorescence performance to identify CN - , and its superparamagnetic behavior plays an important role in removing CN - . The magnetic sensor FSTB shows excellent selectivity and anti-interference for the detection of CN - in aqueous solutions. It is obvious from the equation LOD = 3 δ / S that the limit of detection (LOD) of FSTB for CN - is significantly lower than the permissible level of CN - in drinkable water recommended by the World Health Organization. Therefore, the magnetic sensor FSTB has a wide range of applications for detecting and removing harmful CN - .

Cancer cell metastasis causes 90% of cancer patient death. Detection and targeted capture of cancer cells in vitro are of paramount importance. The development of novel nanodevices for cancer cell capture applications, however, still remains a great challenge. Here we report a facile approach to fabricating multifunctional dendrimer-modified electrospun cellulose acetate (CA) nanofibers for targeted cancer cell capture applications. In this study, hydrolyzed electrospun CA nanofibers with negative surface charge were assembled layer-by-layer with a bilayer of poly(diallyldimethylammonium chloride) (PDADMAC) and polyacrylic acid (PAA) via electrostatic interactions. Thereafter, amine-terminated generation 5 poly(amidoamine) dendrimers pre-modified with folic acid (FA) and fluorescein isothiocyanate were covalently conjugated onto the bilayer-assembled nanofibers via the 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride coupling reaction, followed by acetylation to neutralize the remaining dendrimer surface amines. The formation of electrospun CA nanofibers, assembly of the PDADMAC/PAA bilayer onto the CA nanofibers, and the dendrimer modification on the nanofibers were characterized via different techniques. The formed dendrimer-modified CA nanofibers were then used to capture cancer cells overexpressing FA receptors. We show that the bilayer self-assembly and the subsequent dendrimer modification do not appreciably change the fiber morphology. Importantly, the modification of FA-targeted multifunctional dendrimers renders the CA nanofibers with superior capability to specifically capture cancer cells (KB cells, a model cancer cell line) overexpressing high-affinity FA receptors. The approach to modifying electrospun nanofibers with multifunctional dendrimers may be extended to fabricate other functional nanodevices for capturing different types of cancer cells.