RSC Advances

Xue, Wenchao; Li, Hua; Dugnani, Roberto; Rehman, Hafeez Ur; Zhang, Chunmei; Chen, Yujie; Liu, Hezhou

doi: 10.1039/c8ra00175hpmid: 35541253

In this study, a lead zirconate titanate (PZT)/in situ polymerized polyurethane (PU) composite with three-dimensional (3D) reduced graphene oxide (rGO) as the conductive phase was prepared and the potential of 3D rGO to enhance the damping properties was investigated. The conductivity and damping properties of the composite were systematically investigated. The results show that the conductive threshold of the composite is reached at a very low rGO content of about 0.7 wt% by using the 3D rGO structure. The best damping performance of the piezoelectric damping composite is achieved at the conductive threshold, where the loss factor is 0.22 (almost 41%) higher and the temperature range where tan δ ≥ 0.3 is 13.2 °C (almost 84%) wider than those of the PU matrix. A composite consisting of only PU and rGO sheets without the 3D structure was prepared for comparison. The conductive threshold of this composite is more than 0.9 wt% and the highest tensile strength is 5.63 MPa when the rGO content is 0.6 wt%, indicating that the 3D structure reduces the use of the conductive phase and does not significantly affect the tensile strength of the matrix.

Li, Ping; Qi, Bing; Li, Kun; Xu, Junwei; Liu, Meili; Gu, Xuenan; Niu, Xufeng; Fan, Yubo

doi: 10.1039/c8ra00145fpmid: 35541231

Besides the particle size and surface performance, the shape also plays a key role in drug delivery systems. Red blood cells are the most abundant blood cells in the human body, and are excellent oxygen carriers, due to their unique biconcave discoid shape. In this study, red blood cell (RBC)-like Fe3O4/TbLa3(Bim)12/poly(lactic-co-glycolic acid) (PLGA) composite particles, with magnetic response and bioimaging functions, were prepared by electrospraying. Various electrospraying parameters, such as solvent, PLGA concentration, collecting distance and solution flow rate were investigated in detail to attempt to obtain RBC-like composite particles. The size distribution, morphology, structure, and hydrophobicity–hydrophilicity of particles were characterized. The results revealed the RBC-like Fe3O4/TbLa3(Bim)12/PLGA composite particles exhibited a strong green fluorescence and good magnetic behavior even when incubated with cells. Furthermore, the intensity of the magnetization and fluorescence can be adjusted by changing the contents of Fe3O4 and TbLa3(Bim)12. The effect on cell viability of the RBC-like Fe3O4/TbLa3(Bim)12/PLGA composite particles was evaluated in A549 cells and RBCs, and it was determined to have low cytotoxicity and excellent blood biocompatibility, suggesting that it is a promising candidate for application in drug delivery, targeting and tracking.

Zhan, Xibing; Cai, Xiqing; Zhang, Junying

doi: 10.1039/c7ra13375hpmid: 35541255

A novel cross-linker polymethyl(ketoxime)siloxane (PMKS) with dense pendant reactive groups based on polymethylhydrosiloxane (PMHS) was synthesized via dehydrocoupling reaction. The novel PMKS cross-linker was applied to a hydroxyl-terminated polydimethylsiloxane (HPDMS) matrix to prepare a series of novel RTV silicone rubbers. The chemical structure of PMKS and curing reaction between HPDMS and PMKS by hydrolytic condensation were verified by IR spectroscopy and 1H NMR. Thermal stability and mechanical properties of these novel RTV silicone rubbers have been studied by means of thermal gravimetric analysis (TGA) and universal tensile testing machine, respectively. The results displayed that a pronounced enhancement effect of the novel cross-linker PMKS on thermal stabilities and mechanical properties of RTV silicone rubbers as compared with the traditional cross-linking agent of methyltris(methylethylketoximino)silane (MTKS). Subsequently, the degradation residues were also characterized by FT-IR and X-ray photoelectron spectrometer (XPS). It was found that the striking enhancements in thermal properties and improvements on mechanical properties could be the synergistic effect of the T-type branched structure of PMKS cross-linker, in situ formation of dense PMKS phase in the chain network by self-crosslinking and the uniform distribution of PMKS cross-linker in the HPDMS matrix.

Lin, Hsi-Kuei; Li, Jia-Xing; Wang, Hao-Cheng; Su, Yu-Wei; Wu, Kaung-Hsiung; Wei, Kung-Hwa

doi: 10.1039/c8ra01532epmid: 35541234

In photovoltaic devices, more effective transfer of dissociated electrons and holes from the active layer to the respective electrodes will result in higher fill factors and short-circuit current densities and, thus, enhanced power conversion efficiencies (PCEs). Planar perovskite photovoltaics feature an active layer that can provide a large exciton diffusion length, reaching several micrometers, but require efficient carrier transport layers for charge extraction. In this study, we employed two nanocomposite carrier transfer layers—an electron transport layer (ETL) comprising [6,6]phenyl-C61-butyric acid methyl ester (PC61BM) doped with the small molecule 4,7-diphenyl-1,10-phenanthroline (Bphen), to enhance the electron mobility, and a hole transfer layer (HTL) comprising poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) doped with molybdenum disulfide (MoS2) nanosheets, to enhance the hole mobility. We used ultraviolet photoelectron spectroscopy to determine the energy levels of these composite ETLs and HTLs; atomic force microscopy and scanning electron microscopy to probe their surface structures; and transmission electron microscopy and synchrotron grazing-incidence small-angle X-ray scattering to decipher the structures of the ETLs. Adding a small amount (less than 1%) of Bphen allowed us to tune the energy levels of the ETL and decrease the size of the PC61BM clusters and, therefore, generate more PC61BM aggregation domains to provide more pathways for electron transport, leading to enhanced PCEs of the resulting perovskite devices. We used quantitative pump-probe data to resolve the carrier dynamics from the perovskite to the ETL and HTL, and observed a smaller possibility of carrier recombination and a shorter injection lifetime in the perovskite solar cell doubly modified with carrier transport layers, resulting in an enhancement of the PCE. The PCE reached 16% for a planar inverted perovskite device featuring an ETL incorporating 0.5 wt% Bphen within PC61BM and 0.1 wt% MoS2 within PEDOT:PSS; this PCE is more than 50% higher than the value of 10.2% for the corresponding control device.

Silva, O. Fernando; de Rossi, Rita H.; Correa, N. Mariano; Silber, Juana J.; Falcone, R. Darío

doi: 10.1039/c8ra01482epmid: 35541230

The present work shows the synthesis of a new type of catanionic surfactant, ModCD14–BHD, which involves an anionic amphiphilic cyclodextrin and the cationic benzyl-n-hexadecyldimethylammonium (BHD). It is obtained from the simple association of the cationic surfactant benzyl-n-hexadecyldimethylammonium chloride (BHDC) and β-cyclodextrin (β-CD) monosubstituted with an alkenyl succinate group (Mod-β-CD14). ModCD14–BHD form unilamellar vesicles spontaneously in water, while the individual components (BHDC and Mod-β-CD14) do not. The vesicles were character-ized by dynamic light scattering (DLS), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and 1H NMR techniques. We suggest that the formation of an inclusion complex between some of the cyclodextrins units and the long hydrocarbon moiety of the cationic surfactant play a crucial role in the vesicles formation. Besides, some or the cavities are available to interact with an external guest. We think that the new surfactant molecule has properties that may lead to important applications in biomedical and pharmaceutical sciences.

Wei, Qingshuo; Mukaida, Masakazu; Ding, Wuxiao; Ishida, Takao

doi: 10.1039/c8ra01776jpmid: 35541245

In this study, we demonstrate that conducting polymers could be ideal materials for continuously managing humidity in a wide range of enclosed spaces. We demonstrate a simple battery-driven humidity control unit to manage the humidity in a closed environment and studied humidity-responsive nanocapsules using Zn-coordinated lipid nanovesicles. This study not only promises new applications for conducting polymers but also provides an easy approach for fabricating chambers with a controlled environment, which are often used by physicists, chemists, and biologists.

Uma, Kasimayan; Chen, Shih-Wen; Arjun, Nadarajan; Pan, Guan-Ting; Yang, Thomas C.-K.

doi: 10.1039/c7ra13260cpmid: 35541225

A process for the photo deposition of noble Ag nanoparticles on a core–shell structure of SiO2@α-Fe2O3 nanocomposite spheres was performed to produce a CO photo oxidation catalyst. The structural analyses were carried out for samples produced using different Ag metal nanoparticle weight percentages on SiO2@α-Fe2O3 nanocomposite spheres by X-ray diffraction (XRD), field emission-scanning electron microscopy (FE-SEM), UV-vis spectroscopy, Raman spectroscopy and Fourier transform infrared spectroscopy (FTIR). A computational study was also performed to confirm the existence of the synergic effect of surface plasmon resonance (SPR) for different weight percentages of Ag on the SiO2@α-Fe2O3 nanocomposites. The mechanism for CO oxidation on the catalyst was explored using diffuse reflectance infrared Fourier transform spectroscopy (DRFIT). The CO oxidation results for the Ag (2 wt%)-SiO2@α-Fe2O3 nanocomposite spheres showed 48% higher photocatalytic activity than α-Fe2O3 and SiO2@α-Fe2O3 at stable temperature.

Gu, Jiangjiang; Li, Xinle; Hu, Donghua; Liu, Yanfeng; Zhang, Guiyang; Jia, Xudong; Huang, Wenyu; Xi, Kai

doi: 10.1039/c8ra01085dpmid: 35541280

Carbon dots (CDs) have sparked tremendous attention due to their unique properties and vast potential in diverse fields. Herein, we report a green and cost-effective hydrothermal route for the synthesis of a series of CDs from readily available organics solvents. Since the organics were completely recyclable after the separation of CDs, this method holds immense potential for the large-scale synthesis of CDs. We found the DMF-CDs and DMAc-CDs possessed amphiphilicity and the diameter of amphiphilic DMF-CDs was ca. 3.5 nm with a narrow distribution. Moreover, these amphiphilic CDs emitted blue light under UV irradiation (365 nm) and the quantum yield could reach more than 30%. Due to their good solubility in organic solvent, DMF-CDs were successfully imbedded into polymers (i.e., PS and PMMA), which revealed their potential in painting, coating, and optical devices. In addition, benefiting from high quantum yield and low cytotoxicity, the DMF-CDs in aqueous media were used as fluorescent probes in living cells, which demonstrated their great potential in bio-imaging.

Alam, M. M.; Asiri, Abdullah M.; Uddin, M. T.; Islam, M. A.; Rahman, Mohammed M.

doi: 10.1039/c8ra01734dpmid: 35541273

A reliable xanthine (XNT) chemical sensor was fabricated using a facile wet-chemical method (by co-precipitation) to prepare ZnO/Al2O3/Cr2O3 nanoparticles (NPs) in an alkaline medium at low temperature. Powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR) and ultraviolet-visible spectroscopy (UV-vis) were implemented for detailed characterization of the NPs. To fabricate the working electrode as a XNT chemical sensor probe, a glassy carbon electrode (GCE) with a 0.0316 cm2 surface area was coated with an ethanolic slurry of the prepared ZnO/Al2O3/Cr2O3 NPs to make a thin layer and used to analyse XNT in a phosphate buffer system. To evaluate the analytical performances of the XNT chemical sensor, the calibration curve of XNT was plotted as the relationship of current versus the concentration of XNT. The plotted calibration curve was found to be linear over the LDR (linear dynamic range) of 0.05 nM to 5.0 μM. The assembled XNT electrochemical sensor exhibited the highest sensitivity (70.8861 μA μM−1 cm−2), the lowest detection limit (1.34 ± 0.07 pM), good reproducibility performance with high accuracy and long-term stability with standard results under ambient conditions. This is a simple route to selectively detect XNT with wet-chemically prepared co-doped ZnO/Al2O3/Cr2O3 nanomaterials using a reliable electrochemical method at a large scale for safety within healthcare fields.

Liu, Min; Yu, Xia; Li, Ming; Liao, Naixuan; Bi, Anyao; Jiang, Yueping; Liu, Shao; Gong, Zhicheng; Zeng, Wenbin

doi: 10.1039/c8ra00946epmid: 35541260

Magnesium ions (Mg2+) play essential roles in various physiological and pathological processes, its abnormal homeostasis in cells is related to many diseases, such as diabetes, neuromuscular disorders, hypertension and other cardiovascular disorders. Investigation on the regulation of magnesium in cellular processes has attracted considerable interest in the past several decades. Among those reported strategies, fluorescent imaging technology has become a powerful and cost-effective tool for the real-time monitoring of magnesium distribution, uptake and trafficking, due to its superior features of high sensitivity and non-invasiveness, as well as excellent spatial and temporal fidelity. Herein, we critically summarize the progresses in the intracellular magnesium detection with fluorescent imaging probes. Our discussion focuses on the recent contributions concerning fluorescent imaging probes for mapping magnesium in biological processes. All the candidates are organized according to their acceptor structures. The sensing mechanisms of fluorescent probes are also highly taken into account. Challenges, trends and prospects of fluorescent imaging technology in magnesium detection are also set forth.