Cellular Uptake Mechanism of an Inorganic Nanovehicle and Its Drug Conjugates: Enhanced Efficacy Due To Clathrin-Mediated Endocytosis

We present the mechanism for the cellular uptake of layered double hydroxide (LDH) nanoparticles that are internalized into MNNG/HOS cells principally via clathrin-mediated endocytosis. The intracellular LDHs are highly colocalized with not only typical endocytic proteins, such as clathrin heavy chain, dynamin, and eps15, but also transferrin, a marker of the clathrin-mediated process, suggesting their specific internalization pathway. LDHs loaded with an anticancer drug (MTX−LDH) were also prepared to confirm the efficacy of LDHs as drug delivery systems. The cellular uptake of MTX was higher in MTX−LDH-treated cells than in MTX-treated cells, giving a lower IC50 value for MTX−LDH than for MTX only. The inhibition of the cell cycle was greater for MTX−LDH than for MTX only. This result clearly shows that the internalization of LDH nanoparticles via clathrin-mediated endocytosis may allow the efficient delivery of MTX−LDH in cells and thus enhance drug efficacy

Hybridization of Layered Titanium Oxides and Covalent Organic Nanosheets into Hollow Spheres for High-Performance Sodium-Ion Batteries with Boosted Electrical/Ionic Conductivity and Ultralong Cycle Life

While development of a sodium-ion battery (SIB) cathode has been approached by various routes, research on compatible anodes for advanced SIB systems has not been sufficiently addressed. The anode materials based on titanium oxide typically show low electrical performances in SIB systems primarily due to their low electrical/ionic conductivity. Thus, in this work, layered titanium oxides were hybridized with covalent organic nanosheets (CONs), which exhibited excellent electrical conductivity, to be used as anodes in SIBs. Moreover, to enlarge the accessible areas for sodium ions, the morphology of the hybrid was formulated in the form of a hollow sphere (HS), leading to the highly enhanced ionic conductivity. This synthesis method was based on the expectation of synergetic effects since titanium oxide provides direct electrostatic sodiation sites that shield organic components and CON supports high electrical and ionic conductivity with polarizable sodiation sites. Therefore, the hybrid shows enhanced and stable electrochemical performances as an anode for up to 2600 charge/discharge cycles compared to the HS without CONs. Furthermore, the best reversible capacities obtained from the hybrid were 426.2 and 108.5 mAh/g at current densities of 100 and 6000 mA/g, which are noteworthy results for the TiO2-based material

Phase Transformation from Brucite to Highly Crystalline Layered Double Hydroxide through a Combined Dissolution–Reprecipitation and Substitution Mechanism

We propose the phase transformation of magnesium hydroxide (brucite) to magnesium–aluminum hydroxide (layered double hydroxide: LDH) utilizing solid state brucite and aqueous aluminum­(III) as precursors in order to obtain highly crystalline and large-sized LDH. Under a hydrothermal reaction at 150 °C, the brucite was partially dissolved, and aqueous aluminum precipitated in the form of boehmite within 1.5 h. Then, the precipitated aluminum migrated into the brucite framework to transform the crystal phase of brucite to LDH within 2.3 h of reaction. Time-dependent X-ray diffraction, scanning electron microscopy and high-resolution transmission electron microscopy analyses showed the time-dependent evolution of LDH from brucite. The transformed LDH exhibited crystal growth along the <i>ab</i>-plane direction first followed by crystal growth along the <i>c</i>-axis. Quantitative analysis utilizing inductively coupled plasma-optical emission spectroscopy for both the solid part and supernatant confirmed that the phase transformation was mediated by both dissolution–reprecipitation and isomorphous substitution in the solid state. The solid-state magic angle spin nuclear magnetic resonance spectroscopy for ²⁷Al indicated that the crystal growth of phase-transformed LDH was accompanied by local ordering around Al­(III) in LDH

Bioluminescence-induced photocatalysis on semiconducting oxide nanosheets

A novel semiconductor photocatalytic reaction system employing a photo-emitting enzyme as an internal light source is pro-posed in the present study. The system completely overturns common sense that conventional photocatalytic reactions must require irradiation from an external light source. A horseradish peroxidase (HRP) catalyzing oxidative bioluminescence reaction of luminol in the presence of H2O2 and manganate nanosheets (MNSs) with a narrow bandgap were utilized for an internal light source and semiconductor photocatalysts, respectively, and both of them coexisted in a same reactant solution. In other words, nano-sized light sources were highly dispersed in the solution, resulting in photo-excitation of MNSs over the entire solution. Photo-activated MNSs simultaneously caused oxidation and reduction, where platinum hexachloride anions (PtCl62-) were utilized as a model substance to be reacted photocatalytically. According to X-ray absorption near edge spectroscopy (XANES) of MNSs after the photocatalytic reaction, the anions were mainly transformed into solid phases of PtO2 and/or Pt(OH)4 by reacting with holes in MNSs. In contrast, a control experiment without HRP, i.e. a dark experiment, did not leave any evidence for photocatalytic reaction of PtCl62-. The detailed mechanism and the advantages/disadvantages of the proposed unique system are explained.</p

Surface-Modified Wrinkled Mesoporous Nanosilica as an Effective Adsorbent for Benzene, Toluene, Ethylbenzene, and Xylene in Indoor Air

Surfactant-extracted spherical porous silica nanoparticles with wrinkled structures were synthesized, and their adsorption performance was altered by grafting three organosilanes: n-octyltriethoxysilane, hexadecyltrimethoxysilane, and triethoxyphenylsilane onto their surface. The surface-modified silica nanoparticles were used to capture frequently detected hazardous indoor air chemicals. The physical and chemical properties of the samples were characterized using thermogravimetric analysis, Fourier transform infrared spectroscopy, N2 adsorption–desorption experiments, field-emission scanning electron microscopy, and high-resolution transmission electron microscopy. Although the organosilane surface modification did not significantly change the surface areas and pore structures of porous silica nanoparticles, the capacities of the surface-modified porous silica nanoparticles for capturing benzene, toluene, ethylbenzene, and xylene (BTEX) molecules from air were considerably higher than those of pristine porous silica nanoparticles. The dispersion forces between adsorbates and adsorbents were the primary factor that affected the absorption capacity of the surface-modified porous silica nanoparticles. Consequently, the BTEX capturing potential of surface-modified mesoporous silica featuring a long alkyl chain was high because of the relatively high dispersion force between adsorbates and the adsorbent

Synergistic Inorganic/Inorganic Hybrid Approach for Fabricating a BTX Gas Adsorbent with High Performance and Thermal Stability

Adsorption is an effective strategy for the removal of volatile organic compounds (VOCs), which are among the main sources of severe environmental and health issues, such as global warming and respiratory diseases, respectively. Although carbon-based adsorbents, such as activated carbon, are currently widely adopted as the most promising candidates for the removal of VOCs, their thermal instability and poor recyclability remain major issues. Here, we present the synthesis of the novel hybrid adsorbent, wherein a layered double hydroxide (LDH) is introduced into mesoporous graphene (MG). The inorganic LDH played a critical role in improving the thermal stability of the hybrid LDH@MG material in the adsorption–desorption performance of VOCs. Moreover, it blocked internal micropores that can irreversibly capture VOCs in the carbon struts, resulting in enhanced adsorption recyclability of the hybrid. In the toluene adsorption–desorption cycle experiments at high temperatures, the initial chemisorption capability showed only slight degradation during the three repeated cycles in the hybrid, while it decreased significantly to 30% in the rare MG adsorbent. These results suggest that the hybridization of LDH and MG can be an effective strategy to alleviate the structural and thermal instability of carbon-based absorbents when applied for practical industrial applications

DNA Core@Inorganic Shell

A chemically well-defined Bio Core@Inorganic Shell nanohybrid, which consists of rationally designed DNA molecule core with a size of ∼100 nm and spherical inorganic nanoshell with an overall thickness of ∼10 nm reassembled with exfoliated layered metal hydroxide (MH nanosheets), is prepared. The DNA encapsulation and its release, due to the pH-dependent solubility of the MH nanoshell, plays a crucial role in maximizing the stability of base sequence-manipulated and probe-functionalized DNA molecules with designed information. The present DNA Core@MH Shell nanohybrid can provide wide bioinspired applications converged with nanotechnology, such as an advanced gene delivery system and a biomedical diagnostics, tracing/collection/sensing system for DNA-based information

Interconnected Vanadyl Pyrophosphate Nanonetworks as a Flexible Electrode for High-Voltage and Long-Life Li-Ion Supercapacitors

Engineering vanadium-based materials with high conductivity, superior redox performance, and high operating voltage has attracted widespread attention in energy storage devices. Herein, we demonstrated a simple and feasible phosphorization technique to design three-dimensional (3D) network-like vanadyl pyrophosphate ((VO)2P2O7) nanowires on flexible carbon cloth (CC) (VP-CC). The phosphorization process enabled the VP-CC to increase the electronic conductivity, and the interconnected nano-network of VP-CC opens pathways for fast charge storage during the energy storage processes. Specifically, the 3D VP-CC electrodes and LiClO4 electrolyte designed as a Li-ion supercapacitor (LSC) demonstrate a maximum operating window of 2.0 V with a superior energy density (Ed) of 96 μWh cm–2, power density (Pd) of 10,028 μW cm–2, and outstanding cycling retention (98%) even after 10,000 cycles. In addition, a flexible LSC assembled utilizing VP-CC electrodes with a PVA/Li-based solid-state gel electrolyte exhibits a high capacitance value of 137 mF cm–2 and excellent cycling durability (86%) with a high Ed of 27 μWh cm–2 and Pd of 7237 μW cm–2. Considering excellent energy storage features, the highly conductive vanadium-based material has been utilized as an ideal electrode for various flexible/wearable energy storage devices with superior performance

Data_Sheet_1_Layered Double Hydroxide Nanomaterials Encapsulating Angelica gigas Nakai Extract for Potential Anticancer Nanomedicine.DOC

<p>We prepared hybrids consisting of Angelica gigas Nakai (AGN) root or flower extract and layered double hydroxide (LDH) for potential anticancer nanomedicine, as decursin species (DS) in AGN are known to have anticancer activity. Dimethylsulfoxide solvent was determined hybridization reaction media, as it has affinity to both AGN and LDH moiety. In order to develop inter-particle spaces in LDH, a reversible dehydration-rehydration, so-called reconstruction route, was applied in AGN-LDH hybridization. Quantitative analyses on AGN-LDH hybrids indicated that the content of DS was two times more concentrated in the hybrids than in extract itself. Using X-ray diffraction, FT-IR spectroscopy, scanning electron microscopy, and zeta-potential measurement, we found that AGN extract moiety was incorporated into inter-particle spaces of LDH nanoparticles during the reconstruction reaction. Time-dependent DS release from hybrids at pH 7.4 (physiological condition) and pH 4.5 (lysosomal condition) exhibited a pH-dependent release of extract-incorporated LDH hybrids. An anticancer activity test using HeLa, A549, and HEK293T cells showed that the AGN-LDH hybrid, regardless of extract type, showed enhanced anticancer activity compared with extract alone at an equivalent amount of DS, suggesting a nanomedicine effect of AGN-LDH hybrids.</p