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Synergistic therapeutic effect through the intracellular co-delivery of chemotherapy and biomacromolecule drugs is a novel strategy for improving tumor treatment effectiveness. A triblock copolymer, poly(acrylic acid)-poly(N, Ndiisopropylaminoethyl methacrylate)-poly(N-vinylcaprolactam) (PAA-PDPA-PNVCL), was designed and synthesized for the construction of smart responsive drug carriers. The structure of the polymers was verified by nuclear magnetic resonance spectroscopy (¹H-NMR) and fluorescence spectrophotometer (FL). The transmittances of the polymer solutions under different pH values or temperatures were measured by ultraviolet-visible spectroscopy (UV-Vis). Results showed that the polymer had excellent pH responsiveness and a low critical solution temperature (LCST), which could self-assemble into vesicles with PAA as hydrophilic shell, PDPA as hydrophobic intermediate layer and PNVCL as hydrophilic cavity. Then, the PAA shell layer was crosslinked with disulfide bonds through amide reaction, to improve the structural stability of vesicles and meanwhile introduce the reduction sensitivity. The changes of the particle size, Zeta potential, and morphology of the vesicle under different conditions were studied by dynamic light scattering (DLS) and transmission electron microscopy (TEM). Results showed that the shell-crosslinked vesicles were uniformly sized spherical structure with good pH value and reduction responsiveness. Their drug encapsulation effect and in-vitro release behavior under different pH values and glutathione (GSH) concentrations were studied by UV-Vis and FT-IR. Results showed that the carriers could achieve zoned and co-loading of hydrophobic small molecule drug (doxorubicin (DOX)) and hydrophilic macromolecular protein drug model (bovine serum protein (BSA)). The hydrophobic layer of PDPA and the crosslinked layer of PAA provided dualblockade for drug leakage. The leakage of drugs under normal physiological conditions was low, and the release of DOX and BSA could only be triggered under simulated tumor microenvironment, that is, weak acid and high concentration of GSH conditions. The smart responsive drug carriers constructed in this paper are expected to achieve co-delivery of chemotherapy and biomacromolecule drugs, which have potential application value to the clinical treatment of tumors. [ABSTRACT FROM AUTHOR]

The organic semiconductor poly(3-hexylthiophene) (P3HT) film prepared by the spin-coating method is optimized by dichlorobenzene (o-DCB) solvent added with chloroform (CF). The organic electrochemical transistor (OECT) is obtained using the optimized P3HT film as the channel layer and ion gel as the electrolyte layer. The effect of CF on the roughness and molecular order of P3HT film is inverstigated by atomic force microscopy, UV-visible spectroscopy and Raman spectroscopy. The effect of CF optimization on the electrical properties of the material is studied with a semiconductor parametric analyzer. Results show that CF introduction reduces the roughness of P3HT film and improves the order degree of P3HT molecular arrangement. The CF-optimized OECT exhibits significant synaptic excitatory pulse current characteristics under the stimulation of −0.5 V and −1.0 V electric pulses. Compared to the device without CF optimization, the amplitude of conductance regulation is increased by about twice and 16 times, respectively, along with the improved retention performance. The simulation results show that the accuracy of the neural network based on the CF-optimized OECT in recognizing MNIST（Modified National Institute of Standards and Technology） handwritten digits is increased from 73.6% to 92.7%. This device is expected to play an important role in large-scale neuromorphic computing applications. [ABSTRACT FROM AUTHOR]

One of the most effective methods for improving the storage density of resistive random access memories (RRAMs) is to fabricate 3D vertical stacking devices. By using BP-DDAT(DDAT: S-1-dodecyl-S ′-(α,α′-dimethyl-α′ ′- aceticacid)trithiocarbonate) as a key 2D template and reversible addition-fragmentation chain transfer (RAFT) reagent, a novel poly(N-vinylcarbazole) covalently functionalized black phosphorus derivative (BP-PVK) is successfully synthesized and well-characterized by infrared spectroscopy, X-ray electron spectroscopy and UV-Vis absorption spectroscopy. The environmental stability and solubility of BP nanosheets are greatly improved. Using BP-PVK as active layer, a double-layer vertically stacked RRAM memory device (17×17 stripe array) with a configuration of Al/BP-PVK/Al/BP-PVK/Al is fabricated. The as-fabricated device shows good bistable electrical switching and non-volatile rewritable performance at room temperature, with an ON/OFF current ratio exceeding 10³, higher production yield of the memory devices and structural uniformity. [ABSTRACT FROM AUTHOR]

Poly(3,4-ethylenedioxythiophene) (PEDOT) is used in organic-inorganic heterojunction based ultraviolet (UV) photodetector due to its good environmental stability, high conductivity and special photoelectric characteristics. The commonly used methods for depositing PEDOT films include solution spin coating, electrochemical polymerization, vacuum evaporation and immersion. In this paper, PEDOT film on the surface of fluorine doped tin oxide (FTO) coated glass conductive glass is obtained by solid-state polymerization, using 2,5-dibromo-3,4-ethylenedioxythiophene (DBEDOT) as monomer. The PEDOT film modified FTO was combined with zinc oxide nano arrays (ZnO NRs) modified FTO to fabricate the organic-inorganic heterojunction based UV photodetector, and the performance of UV photodetection ability was studied. The materials were characterized by ultraviolet-visible spectroscopy (UV-Vis), Fourier-transfer infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and X-ray powder diffractometry (XRD). The photo-responsivity, response speed and stability of the UV photodetector were examined in detail through current-voltag (I-V), current-time (I-t) and Tafel curves at zero bias voltage under UV irradiation (365 nm, 0.32 mW/cm²). Results showed that the PEDOT film had a large flake structure, which was conducive to the good contact of ZnO NRs to build a better p-n heterojunction. Furthermore, the introduction of PEDOT film effectively solved the problems of short carrier life, high recombination rate of hole-electrons and slow light response speed of ZnO NRs. In a word, the PEDOT film enhanced the optoelectronic performance of ZnO NRs, which possessed high responsivity of 15.34 mA/W, fast response time of 0.159 s/0.162 s (rise time/fall time) under UV irradiation (365 nm, 0.32 mW/cm²) and good stability. [ABSTRACT FROM AUTHOR]

Polyvinylidene fluoride (PVDF) and tetrabutyl titanate (TBOT) are dissolved in a mixed solvent of N, N'- dimethylformamide (DMF) and acetone to electrospun into a fiber membrane. Then, TBOT contained in the electrospun fiber membrane was reduced to titanium dioxide (TiO2) by a one-step hydrothermal method at 150 °C. The PVDF fiber membrane material with TiO2 grown in situ on the surface and inside of the fiber was obtained. The morphology and structure of TiO2 grown on PVDF fibers in situ were determined by scanning electron microscopy (SEM), thermal gravity (TG), X-ray diffractometer (XRD) and Fourier infrared absorption spectroscopy (FT-IR). Then, the degradation effect of the composite film on the three organic dyes (rhodamine B, methyl orange and methylene blue) was tested by UV-visible spectroscopy. Finally, the gravity-driven method was used to separate the oil-water mixture, and the contact angle of the composite membrane to water and oil was tested to explore the oil-water separation effect of the composite membrane. Results show that the composite membrane has a good degradation effect on organic dyes such as rhodamine B, methyl orange, methylene blue. The composite membrane also has good lipophilic and hydrophobic properties. It is separated by a mixture of carbon tetrachloride and water. The composite membrane can effectively realize oil-water separation, and the oil-water separation efficiency can be as high as 98.2%. [ABSTRACT FROM AUTHOR]

Organic filters in conventional sunscreens generally have poor photo stability and can easily penetrate through stratum corneum and dermis into the blood vessel, thus causing potential health-threatening issues. Polydopamine (PDA) nanoparticles can be formed by self-polymerization of dopamine. Inspired by its excellent anti-ultraviolet, free radical scavenging and adhesion properties, the titanium dioxide (TiO2) precursor is prepared by the sol-gel method and blended with dopamine hydrochloride to prepare PDA-TiO2 hybrid nanoparticles. Infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet-visible absorption spectroscopy (UV-Vis), thermogravimetric analysis (TGA) and skin penetration experiments were used to characterize the basic structures and properties of nanoparticles. Under the synergistic effect of PDA and TiO2, the particles have highly efficient UV protection. By simply adjusting the reaction material ratio, it was found that the more dopamine content, the better UV absorption effect was obtained, and it showed better UV absorption performance than small particle size PDA. Therefore, PDA-TiO2 (1/10) (m (DA)∶m(TiO2)=1∶10) had the best UV absorption effect. The PDA-TiO2 (1/10) was introduced as the sole active ingredient to formulating sunscreen, whose sun protection factor (SPF) values could reach 33.7, which can meet daily sun protection needs. Most importantly, PDA had good bioadhesion and can effectively prevent the penetration of PDA-TiO2 hybrid nanoparticles. The thickness of the stratum corneum of the human body was about 15—20 μm. Upon comparing the PDA-TiO2 with commercially available benzophenone small molecule sunscreens, it was found that the skin permeability of PDA-TiO2 was significantly reduced. The penetration depth was 9 —17 μm, mainly distributed in the upper and middle parts of the stratum corneum of the skin. It is not easy to enter the human body and will not pose a potential threat to skin health. The commercially available benzophenone sunscreen small molecules had a skin penetration of 18 —35 μm, indicating that they penetrate the stratum corneum to reach the living epidermis and enter the human body. Therefore, the prepared nanoparticles have excellent UV resistance and biocompatibility, ensuring their excellent performance and safe use in sunscreens. [ABSTRACT FROM AUTHOR]

Quaternized chitosan/nano-zinc oxide (QAC/ZnO) hybrid colloidal particles were prepared by the self-assembly of quaternized chitosan (QAC), L-cysteine (L-cys) and the precursor of nano-zinc oxide Zn(CH3COO)2·2H2O. The chemical composition of QAC/ZnO hybrid colloidal particles was determined by Fourier transform-infrared spectroscopy (FT-IR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and thermogravimetic analysis(TG). The morphology and particle size of the hybrid colloidal particles were investigated in detail by means of Zeta potential analyzer, nanoparticle size analyzer and transmission electron microscopy (TEM). The ultraviolet transmittance, oxidation resistance, photocatalytic activity and cytotoxicity of the hybrid colloidal particles were studied by UV-Vis spectroscopy and the in vitro cell experiments. The results show that spherical QAC/ZnO hybrid colloidal particles can be successfully prepared by the selfassembly of QAC, L-cys and the precursor of nano-zinc oxide, and the size of the hybrid colloidal particles can be controlled by the concentration of nano-zinc oxide precursor. QAC/ZnO hybrid colloidal particles have good ultraviolet shielding property, excellent antioxidant property and low cytotoxicity. Moreover, the photocatalytic activity of the QAC/ZnO hybrid colloidal particles are significantly reduced in comparison with ZnO. It is expected to be used in cosmetics as an ultraviolet absorbent. [ABSTRACT FROM AUTHOR]