Search

Cisplatin (CDDP) is a widely used chemotherapeutic drug with proven efficacy for treating tumors. However, its use has been associated with severe side effects and eventually leads to drug resistance, thus limiting its clinical application in patients with ovarian cancer (OC). Herein, we aimed to investigate the success rate of reversing cisplatin resistance using a synthetic, multitargeted nanodrug delivery system comprising a Mn-based metal-organic framework (Mn-MOF) containing niraparib (Nira) and CDDP alongside transferrin (Tf) conjugated to the surface (Tf-Mn-MOF@Nira@CDDP; MNCT). Our results revealed that MNCT can target the tumor site, consume glutathione (GSH), which is highly expressed in drug-resistant cells, and then decompose to release the encapsulated Nira and CDDP. Nira and CDDP play a synergistic role in increasing DNA damage and apoptosis, exhibiting excellent antiproliferation, migration, and invasion activities. In addition, MNCT significantly inhibited tumor growth in tumor-bearing mice and exhibited excellent biocompatibility without side effects. Furthermore, it depleted GSH, downregulated multidrug-resistant transporter protein ( MDR ) expression, and upregulated tumor suppressor protein phosphatase and tensin homolog ( PTEN ) expression, consequently reducing DNA damage repair and reversing cisplatin resistance. These results indicate that multitargeted nanodrug delivery systems can provide a promising clinical approach to overcoming cisplatin resistance. This study provides an experimental basis for further investigation into multitargeted nanodrug delivery systems to reverse cisplatin resistance in patients with OC.

Reactive oxygen species (ROS)-based anticancer therapy methods were heavily dependent on specific tumor microenvironments such as acidity and excess hydrogen peroxide (H 2 O 2 ). In this work, an acidity-sensitive nanotheranostic agent (FePt@MnO)@DSPE-PEG5000-FA (FMDF NPs)  was successfully constructed for MR imaging guided ferroptosis chemodynamic therapy (FCDT) of cancer. The FMDF NPs could specifically target folic acid (FA) receptor-positive tumor cells (HeLa etc.) and induce ferroptosis efficiently by rapidly releasing active Fe 2+ to catalyze intracellular H 2 O 2 into ROS based on Fenton reaction. On the other hand, the Mn 2+ could also be released due to acidity  and further coordinate with GSH to enhance the longitudinal-transverse relaxivity (T 1 /T 2 -weighted MR imaging), which could obviously strengthen the contrast distinction between solid tumors and the surrounding tissue to accurately real-time monitor the tumor location. Furthermore, the in vivo anticancer study revealed that the growth of solid tumor models could be suppressed remarkably after treating with FMDF NPs and no obvious damage to other major organs. Therefore, the FMDF NPs were competent simultaneously as an enhanced imaging diagnosis contrast agent and efficient therapy agent for promoting more precise and effective treatment in the bionanomedicine field.

Drug-loaded nanoparticles can be specifically uptaken by tumor cells to realize active targeting due to the conjugated ligands or antibodies on their surface. However, some non-cancerous cells express non-specific receptors or antigens on their surface, which can react with the ligands or antibodies conjugated on the nanoparticle surface and then result in non-specific uptake of the nanoparticles by non-cancerous cells. In order to reduce the non-specific uptake of nanoparticles by non-cancerous cells, in this study, we proposed a pH-sensitive polymer based precise tumor targeting strategy and synthesized superparamagnetic iron oxide nanoparticle (SPION) encapsulated albumin nanoparticles (AN) with conjugation of folic acid (FA) and mPEG-DCA (SPION-AN-FA@mPEG), in which mPEG can shield FA, avoiding the non-specific recognition by normal cells under physiological conditions, and can be shed to expose FA in tumor microenvironments. The pH-sensitivity of mPEG-DCA was verified by HPLC characterization and 1H-NMR spectroscopy. The graft density and length of mPEG-DCA were optimized via the cellular uptake of SPION-AN-FA@mPEG measured by flow cytometry analysis. The r2 value and r2/r1 ratio of the optimized SPION-AN-FA@mPEG (i.e., SPION-AN-FA@mPEG4) are 168.6 mM-1 s-1 and 42.8, respectively, which are both much higher than that of the commercial contrast agent Resovist®. The in vitro T2-weighted MR images and in vivo MRI performance demonstrate that our SPION-AN-FA@mPEG4 nanoparticles can be used as an effective T2-weighted MRI contrast agent.

Abstract Wound dehiscence is a surgical complication and its management is inevitable because 25% to 35% of patients suffered from post laparotomy wound dehiscence. The excellent biodegradability and biocompatibility of chitosan and alginate have provided ample space for future developments in biomedical applications. Hence, the present work is directed towards the synthesis of robust biofilm made up of chitosan (CS), zinc oxide (ZnO) nanoparticles and Alginate (Alg). Chitosan and alginate were used for their pore forming ability, and ZnO is for its antibacterial action. The proposed biofilm was characterized with different characterization techniques such as Fourier Transform Infrared (FTIR) spectroscopy, UV–vis spectroscopy, X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Transmission Electron microscopy (TEM) analyses. FTIR results inferred the strong interaction between the three components. The surface morphology of ZnO-CS/Alg. biofilm was exhibited as the spherical shaped nanoparticles which are firmly anchored on the polymer matrix. TEM analysis also confirmed the formation of biofilm. The XRD analysis confirmed the presence of ZnO in the biopolymer. The line broadening suggests that the crystallize size is in few nanometers. The average crystallite size was estimated as 50 nm using Scherrer formula. The antibacterial activity of the biofilm was successfully established against bacterial pathogens. Therefore, the developed materials have a potential play as antimicrobial role for the abdominal wound healing and biomedical fields. Graphical Abstract Unlabelled Image Highlights • Synthesis of robust biofilm made up of chitosan, ZnO nanoparticles and Alignate • Biopolymers were used for their pore forming ability, and ZnO is for its antibacterial action. • Microscopic and spectroscopic analysis also confirmed the formation of biofilm. • Developed materials have played for antimicrobial and abdominal wound site healing. [ABSTRACT FROM AUTHOR]

Abstract: Two unique ZnI‐containing MOFs {[ZnI8ZnII3(H2O)x(HL)12](OH)2⋅13 H2O}n (x=6, 1; x=2, 2) (HL=tetrazole monoanion) with high‐nuclearity Zn‐cages were prepared successfully. These Zn‐cages are constructed from [ZnI8] clusters with multi‐centered ZnI−ZnI bonds and ZnII ions. [ZnI8] clusters in 1 and 2 display Oh and D4h symmetry, respectively. Importantly, eight [ZnI8] clusters and six ZnII ions form a large [Zn70] nanocage in 1. To our knowledge, this is the first MOF based on polynuclear Zn‐cages consisting of ZnI and ZnII ions. Compared with reported ZnI‐species, 1 and 2 display high thermal and solvent stabilities. Theoretical investigations based on DFT calculations uncover that effective 4s‐4s orbital overlap and electron delocalization through these a1g+t1u molecular orbitals on [ZnI8] clusters lead to considerable aromatic stabilization, which can explain well the intrinsic stability of 1 and 2. Interestingly, 1 can behave as a luminescent probe to detect the toxic CrVI ions in aqueous. [ABSTRACT FROM AUTHOR]

ZnO and Al-doped ZnO ceramics with high density and fine grain size were prepared using a two-step sintering method. ZnO ceramics with a grain size of 1.2 μm and a density greater than 99% were obtained. The kinetic window for a ZnO nanoparticle TSS process was determined in this study. Dense AZO ceramics with homogeneous Al distribution were obtained using a high sintering temperature ( Tst) of 1323 K and a low sintering temperature ( Tnd) of 1273 K. The activation energies for ZnO and AZO nanoparticle grain growth were determined to be 169 ± 18 kJ/mol and 374 ± 36 kJ/mol, respectively. [ABSTRACT FROM AUTHOR]

Abstract: Compounds LiNi1−x Sb x O2 (x=0, 0.1, 0.15, 0.2, 0.25) were synthesized by the two-step calcination method. The structural and morphological properties of the products were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). XRD analysis confirms that the uniform solid solution has been formed in the as-prepared compounds without any impurities. It is shown that the crystal lattice parameters (a, c) of the Sb-doped compounds are bigger than those of pure LiNiO2 and the Sb-doped compound with x=0.2 consists of spherical-like nanoparticles with a mean grain size of 50nm. The electrochemical performances of as-prepared samples were studied via galvanostatic charge–discharge cycling tests. The compound with x=0.2 exhibits excellent capacity retention during the charge–discharge processes due to its reinforced structural stability, and a discharge capacity of 102.4mAh/g is still obtained in the voltage range of 2.5–4.5V after 20 cycles. Thermal analysis further confirms that the structural stability of LiNi0.8Sb0.2O2 is superior to that of pure LiNiO2. [Copyright &y& Elsevier]

kind of titanium oxide nanoparticles modified with varying amounts of oxalate group was prepared using a modified hydrolysis method. The microstructure, dielectric properties, and electrorheological (ER) performance were investigated. The results indicate that the oxalate group can effectively improve the dielectric properties and surface polarizability of the particles, and the ER performance of modified titanium oxide-based ER fluid is much higher than that of pure titanium oxide-based ER fluid. The shear stress of suitable oxalate group-modified amorphous titanium oxide-based ER fluid with a volume fraction of 30% reaches 47.5 kPa at E = 5 kV/mm, and the current density is less than 18 μAcm. The yield stress can be up to 114 kPa at E = 5 kV/mm with a volume fraction of 40%. [ABSTRACT FROM AUTHOR]

Two types of amorphous TiO2 particles with different particle sizes were synthesized by a simple sol–gel method and were characterized by X-ray diffraction analysis, field emission scanning electron microscopy, and Fourier transform infrared spectrometry. The electrorheological (ER) results show that the TiO2/silicone oil suspensions exhibited a remarkable ER effect. The static shear stress can be up to 130 kPa (shear rate 0.2 s − 1) under the DC electric field of 4 kV/mm at room temperature. The polar molecules present on the particles’ surface play a decisive role for the observed giant ER effect, which arises from the alignment of polar molecules in the gap between neighboring particles. [ABSTRACT FROM AUTHOR]

Isothermal crystallization from the glassy state of pure poly(ethylene terephthalate)(PET) and PET/Silica nanocomposites films was studied. The results showed that addition of nano-silica increased the crystallinity of filled PET compared to pure PET, suggesting that nano-silica is an effective nucleating agent. However, the induction period prior to crystallization was prolonged and the overall crystallization rate decreased through nano-silica incorporation. This is a result of the cold crystallization rate being primarily controlled by diffusion of PET chains, rather than being controlled by the nucleation rate. The strong interaction between the nanoparticles and PET chains confined the movement of the macromolecular chains and decreased the cold crystallization rate. [ABSTRACT FROM AUTHOR]

The crystallization process of poly(ethylene terephthalate)/silica nanocomposites were investigated by differential scanning calorimetry (DSC) and then analyzed using the Avrami method. The results indicated that the crystallization of pure poly(ethylene terephthalate) (PET) was fitted for thermal nucleation and three‐dimensional spherical growth throughout the whole process, whereas the crystallization of PET/silica nanocomposites exhibits two stages. The first stage corresponds to athermal nucleation and three‐dimensional spherical growth, and the second stage corresponds to recrystallization caused by the earlier spherulites impingement. The crystallization rate increases remarkably and the activation energies decrease considerably when silica nanoparticles are added. The subsequent melting behavior of the crystallized samples shows that the melting point ( T m ) of nanocomposites is higher than that of pure PET, which might be caused by two factors: (1) The higher melting point might be due to some hindrance to the PET chains caused by the nanoparticles at the beginning of the melting process; (2) it might also be the case that more perfect crystals can be formed due to the higher crystallization temperatures and lower activation energies of PET/silica nanocomposites. [ABSTRACT FROM AUTHOR]

In this study, dicyandiamide (DCDA) modified polystyrene (PS) resin beads decorated with nano‐Fe3O4 (Fe3O4‐PS‐DCDA hybrids) were prepared by co‐precipitation method. The Fe3O4‐PS‐DCDA hybrids were characterized by scanning electron microscopy (SEM), Fourier transform‐infrared (FT‐IR) spectroscopy, X‐ray diffraction (XRD) spectroscopy, X‐ray photoelectron spectroscopy (XPS), nitrogen adsorption/desorption isotherms, and vibrating sample magnetometer (VSM). Meanwhile, the adsorption property of Fe3O4‐PS‐DCDA hybrids for Hg(II) in aqueous solution was investigated by batch methods. The results show that the nano‐Fe3O4 decorated on the outer surface and interior of DCDA modified PS resin beads (PS‐DCDA) is nanoparticles and nanorods, respectively. The saturation magnetization (Ms) of the Fe3O4‐PS‐DCDA hybrids is 0.70 emu/g, which is enough to ensure the convenient magnetic separation. The adsorption kinetics of the hybrids for Hg(II) accorded with the pseudo‐second‐order model and the adsorption isotherms followed the Freundlich equation. POLYM. COMPOS., 39:2232–2240, 2018. © 2016 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Abstract: In this paper, dynamic mechanical analyzer (DMA) and differential scanning calorimetry (DSC) were used to study the melting behavior of Indium (In) nanoparticles dispersed in an aluminum (Al) matrix made by high energy ball milling method. DMA results show that an internal friction peak appears in the vicinity of the In melting point and there exists a linear relationship between the height of internal friction peaks and the total surface area of the In nanoparticles. In contrast, DSC results demonstrate that the endothermic peaks corresponding to the melting of the In nanoparticles with different surface area are all similar. The mechanism of the internal friction peaks is discussed in detail from the viewpoint of surface melting. The study shows that DMA is an ideal technique for studying surface melting of nanoparticles. [Copyright &y& Elsevier]

Abstract: Pb nanoparticles embedded in an Al matrix were prepared by ball milling and the internal friction behavior associated with the melting of Pb nanoparticles was studied by means of dynamic mechanical analyzer. The height H of internal friction peak was found to be dependent on the frequencies and heating rates, which indicates a first-order phase transition of Pb melting. The internal friction behavior of Pb nanoparticles is discussed with respect to the surface melting. [Copyright &y& Elsevier]

The 3D spherical NiO@MnO 2 composites grown on Ni foam with core-shell structure were prepared by a hydrothermal process followed by a chemical bath deposition process, and then the mechanism improving the electrochemical performance of NiO by MnO 2 modification were investigated by the first-principles calculations for the first time. This core-shell structure promotes an efficient contact between electrolyte and active materials, and the distinct architecture can offer fast transfer channels of ion and electrons. The initial capacitances of NiO, NiO@MnO 2 (deposition time of MnO 2 is 20 min), NiO@MnO 2 (deposition time of MnO 2 is 30 min) and NiO@MnO 2 (deposition time of MnO 2 is 60 min) at 10 A g−1 are 931.6, 1064.4, 1227.2 and 766.8 F g−1, respectively. After 10000 cycles, the reversible capacitances attenuate to 352.8, 661.0, 1089.4 and 616.6 F g−1, respectively. NiO@MnO 2 (deposition time of MnO 2 is 30 min) shows the most excellent reversible capacitance at each cycle and the highest retention rates after 10000 cycles among all samples. The first-principles calculation confirms that a strong interfacial interaction between NiO and MnO 2 can be generated, and then the atomic relaxations at the interface are rather small due to the well-matched interface and epitaxial bonding, resulting in a relatively small interfacial polarization of NiO@MnO 2 composites during cycling. The outstanding rate capability and cycle performance of NiO@MnO 2 (deposition time of MnO 2 is 30 min) electrode are attributed to the synergistic effect and particular 3 D architectures. [ABSTRACT FROM AUTHOR]

Graphene is a promising material for designing next-generation electronic and valleytronic devices, which often demand the opening of a bandgap in the otherwise gapless pristine graphene. To date, several conceptually different mechanisms have been extensively exploited to induce bandgaps in graphene, including spin–orbit coupling and inversion symmetry breaking for monolayer graphene, and quantum confinement for graphene nanoribbons (GNRs). Here, we present a multiscale study of the competing gap opening mechanisms in a graphene overlayer and GNRs proximity-coupled to topological insulators (TIs). We obtain sizable graphene bandgaps even without inversion symmetry breaking and identify the Kekulé lattice distortions caused by the TI substrates to be the dominant gap opening mechanism. Furthermore, Kekulé distorted armchair GNRs display intriguing nonmonotonous gap dependence on the nanoribbon width, resulting from the coexistence of quantum confinement, edge passivation, and Kekulé distortions. The present study offers viable new approaches for tunable bandgap engineering in graphene and GNRs. [ABSTRACT FROM AUTHOR]

Abstract: A new method is presented for preparing monodisperse and uniform-size silica nanoparticles using a two-stage hydrolysis of silicon powder in aqueous medium. The influence of synthesis conditions including solution composition and temperature on the formation of silica nanoparticles were systematically investigated. The structure and morphology of the silica particles were characterized via transmission electron microscopy (TEM) and dynamic light scattering (DLS). Various-sized particles in the range 10–100 nm were synthesized. The size of the nanoparticles can be precisely controlled by using a facile regrowth procedure in the same reaction media. [Copyright &y& Elsevier]