Nonaqueous Lyotropic Liquid-Crystalline Phases Formed by Gemini Surfactants in a Protic Ionic Liquid

The aggregation behaviors of three Gemini surfactants [(C_<i>s</i>H_2<i>s</i>-α,ω-(Me₂N⁺C_<i>m</i>H_2<i>m</i>+1Br^–)₂, <i>s</i> = 2, <i>m</i> = 10, 12, 14] in a protic ionic liquid, ethylammonium nitrate (EAN), have been investigated. The polarized optical microscopy and small-angle X-ray scattering (SAXS) measurements are used to explore the lyotropic liquid crystal (LLC) formation. Compared to the LLCs formed in aqueous environment, the normal hexagonal and lamellar phases disappear. However, with increasing the surfactant concentration, a new reverse hexagonal phase (H_II) can be mapped over a large temperature range except for other ordered aggregates including the isotropic solution phase and a two-phase coexistence region. The structural parameters of the H_II are calculated from the corresponding SAXS patterns, showing the influence of surfactant amount, alkyl chain length, and temperature. Meanwhile, the rheological profiles indicate a typical Maxwell behavior of the LLC phases formed in EAN

Targeting Chemophotothermal Therapy of Hepatoma by Gold Nanorods/Graphene Oxide Core/Shell Nanocomposites

Nanographene oxide (NGO) are highly suitable to be the shells of inorganic nanomaterials to enhance their biocompatibility and hydrophilicity for biomedical applications while retaining their useful photonic, magnetic, or radiological functions. In this study, a novel nanostructure with gold nanorods (AuNRs) encapsulated in NGO shells is developed to be an ultraefficient chemophotothermal cancer therapy agent. The NGO shells decrease the toxicity of surfactant-coated AuNRs and provide anchor points for the conjugation of hyaluronic acid (HA). The HA-conjugated NGO-enwrapped AuNR nanocomposites (NGOHA-AuNRs) perform higher photothermal efficiency than AuNRs and have the capability of targeting hepatoma Huh-7 cells. NGOHA-AuNR is applied to load doxorubicin (DOX), and it exhibits pH-responsive and near-infrared light-triggered drug-release properties. Chemophotothermal combined therapy by NGOHA-AuNRs-DOX performs 1.5-fold and 4-fold higher targeting cell death rates than single chemotherapy and photothermal therapy, respectively, with biosafety to nontargeting cells simultaneously. Furthermore, our strategy could be extended to constructing other NGO-encapsulated functional nanomaterial-based carrier systems

Ultrahigh Sensitivity of Au/1D α‑Fe₂O₃ to Acetone and the Sensing Mechanism

Hematite (α-Fe₂O₃) is a nontoxic, stable, versatile material that is widely used in catalysis and sensors. Its functionality in sensing organic molecules such as acetone is of great interest because it can result in potential medical applications. In this report, microwave irradiation is applied in the preparation of one-dimensional (1D) α-FeOOH, thereby simplifying our previous hydrothermal method and reducing the reaction time to just a few minutes. Upon calcination, the sample was converted to porous α-Fe₂O₃ nanorods, which were then decorated homogeneously by fine Au particles, yielding Au/1D α-Fe₂O₃ at nominally 3 wt % Au. After calcination, the sample was tested as a potential sensor for acetone in the parts per million range and compared to a similarly loaded Pt sample and the pure 1D α-Fe₂O₃ support. Gold addition results in a much enhanced response whereas Pt confers little or no improvement. From tests on acetone in the 1–100 ppm range in humid air, Au/1D α-Fe₂O₃ has a fast response, short recovery time, and an almost linear response to the acetone concentration. The optimum working temperature was found to be 270 °C, which was judged to be a compromise between the thermal activation of lattice oxygen in hematite and the propensity for acetone adsorption. The surface reaction was investigated by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), and a possible sensing mechanism is proposed. The presence of Au nanoparticles is believed to promote the dissociation of molecular oxygen better in replenishing O vacancies, thereby increasing the instantaneous supply of lattice oxygen to the oxidation of acetone (to H₂O and CO₂), which proceeds through an adsorbed acetate intermediate. This work contributes to the development of next-generation sensors, which offer ultrahigh detection capabilities for organic molecules

Temperature-Dependent Abnormal and Tunable p‑n Response of Tungsten Oxide–Tin Oxide Based Gas Sensors

We observed the sensing response of temperature-dependent abnormal p–n transitions in WO₃–SnO₂ hybrid hollow sphere based gas sensors for the first time. The sensors presented a normal n-type response to ethanol at elevated temperatures but abnormal p-type responses in a wide range of operation temperatures (room temperature to about 95 °C). By measuring various reducing gases and applying complex impedance plotting techniques, we demonstrated the abnormal p-type sensing behavior to be a pseudo-response resulting from the reaction between target gas and adsorbed water on the material surface. The temperature-controlled n–p switch is ascribed to the competition of intrinsic and extrinsic sensing behaviors, which resulted from the reaction of target gas with adsorbed oxygen ions and protons from adsorbed water, respectively. The former can modulate the intrinsic conductivity of the sensor by changing the electron concentration of the sensing materials, while the latter can regulate the conduction of the water layer, which contributes to the total conductivity as an external part. The hollow and hybrid nanostructures facilitated the observation of extrinsic sensing behaviors due to its large-area active sites and abundant oxygen vacancies, which could enhance the adsorption of water. This work might give new insight into gas sensing mechanisms and opens up a promising way to develop practical temperature and humidity controllable gas sensors with little power consumption based on the extrinsic properties

Three-Dimensional Co₃O₄@NiMoO₄ Core/Shell Nanowire Arrays on Ni Foam for Electrochemical Energy Storage

In this work, we report a facile two-step hydrothermal method to synthesize the unique three-dimensional Co₃O₄@NiMoO₄ core/shell nanowire arrays (NWAs) on Ni foam for the first time. The Co₃O₄ nanowires are fully covered by ultrathin mesoporous NiMoO₄ nanosheets. When evaluated as a binder-free electrode for supercapacitors in a 2 M KOH aqueous solution, the Co₃O₄@NiMoO₄ hybrid electrode exhibits a greatly enhanced areal capacitance of 5.69 F cm^–2 at a high current density of 30 mA cm^–2, nearly 5 times that of the pristine Co₃O₄ electrode (1.10 F cm^–2). The energy density of the hybrid electrode is 56.9 W h kg^–1 at a high power density of 5000 W kg^–1. In addition, the Co₃O₄@NiMoO₄ hybrid electrode also exhibits good rate capability and cycling stability, which would hold great promise for electrochemical energy storage

Encapsulating Gold Nanoparticles or Nanorods in Graphene Oxide Shells as a Novel Gene Vector

Surface modification of inorganic nanoparticles (NPs) is extremely necessary for biomedical applications. However, the processes of conjugating ligands to NPs surface are complicated with low yield. In this study, a hydrophilic shell with excellent biocompatibility was successfully constructed on individual gold NPs or gold nanorods (NRs) by encapsulating NPs or NRs in graphene oxide (GO) nanosheets through electrostatic self-assembly. This versatile and facile approach remarkably decreased the cytotoxicity of gold NPs or NRs capping with surfactant cetyltrimethylammonium bromide (CTAB) and provided abundant functional groups on NPs surface for further linkage of polyethylenimine (PEI). The PEI-functionalized GO-encapsulating gold NPs (GOPEI-AuNPs) were applied to delivery DNA into HeLa cells as a novel gene vector. It exhibited high transfection efficiency of 65% while retaining 90% viability of HeLa cells. The efficiency was comparable to commercialized PEI 25 kDa with the cytotoxicity much less than PEI. Moreover, the results on transfection efficiency was higher than PEI-functionalized GO, which can be attributed to the small size of NPs/DNA complex (150 nm at the optimal w/w ratio) and the spherical structure facilitating the cellular uptake. Our work paves the way for future studies focusing on GO-encapsulating, NP-based nanovectors

Low-Temperature H₂S Detection with Hierarchical Cr-Doped WO₃ Microspheres

Hierarchical Cr-doped WO₃ microspheres have been successfully synthesized for efficient sensing of H₂S gas at low temperatures. The hierarchical structures provide an effective gas diffusion path via well-aligned micro-, meso-, and macroporous architectures, resulting in significant enhancement in sensing response to H₂S. The temperature and gas concentration dependence on the sensing properties elucidate that Cr dopants remarkably improve the response and lower the sensor’ operating temperature down to 80 °C. Under 0.1 vol % H₂S, the response of Cr-doped WO₃ sensor is 6 times larger than pristine WO₃ sensor at 80 °C. We suggest the increasing number of oxygen vacancies created by Cr dopants to be the underlying reason for enhancement of charge carrier density and accelerated reactions with H₂S

Real-time RT-PCR analysis of retinal expression of inflammatory cytokines: VEGF, MCP1, ICAM1 and TNFα.

<p>Values on y-axis represent fold change in mRNA levels compared to WT (normalized as 1). *P<0.01 (vs. DM Ren2+vehicle group). WT, wildtype, DM/NDM, diabetic/nondiabetic. N = 5.</p

Representative retinal micrographs of wildtype (WT) Sprague–Dawley rats, non-diabetic (NDM) Ren2 rats, and diabetic (DM) Ren2 rats treated with vehicle, aliskiren or aliskiren+HRP (A).

<p>INL: inner nuclear layer; IPL: inner plexiform layer; RGC: retinal ganglion cell layer. Quantitative measurement of cell density in RGC layer in the central (B) and peripheral (C) retinas of wildtype (WT) Sprague–Dawley rats, non-diabetic (NDM) Ren2 rats, and diabetic (DM) Ren2 rats treated with vehicle, aliskiren or aliskiren+HRP. N = 4. *p<0.01 (vs. WT).</p

In situ cell death detection in the retina.

<p>A, Apoptotic cells were detected in-diabetic (NDM) Ren2 rats (a & b), diabetic (DM) Ren2 rats treated with vehicle (c & d), and aliskiren (e & f). ONL: outer nuclear layer; INL: inner nuclear layer; RGC: retinal ganglion cell layer. B, Quantitative measurement of apoptotic cells detected by TUNEL assay. #p<0.01 (vs. wildtype (WT) Sprague–Dawley rats); $p<0.01 (vs. NDM Ren2 and WT); *p<0.01 (vs. NDM Ren2 and DM Ren2+ vehicle).</p