Preparation and in vivo safety evaluations of antileukemic homoharringtonine-loaded PEGylated liposomes

In order to improve the in vivo safety and specific delivery efficiency of the antileukemic homoharringtonine (HHT) at the targets, the long-circulating PEGylated liposomes loaded with HHT (LCLipo-HHT) were prepared. Their physical characteristics, in vitro drug release, in vivo pharmacokinetic properties and elementary toxicity were evaluated. The mean diameter of the prepared LCLipo-HHT is 75.6?±?3.2?nm and the zeta potential is ?16.9?±?2.5?mV. The entrapment efficiency of HHT in the liposomes is 69.5?±?1.7%. In pharmacokinetic experiments, an increased plasma concentration as well as blood circulation time was obtained when distearoyl phosphoethanolamine-PEG 2000 lipid was added in the formulation, which results in enhancing drug delivery efficiency. Hemolysis test, vascular irritation test and acute toxicity test were used to demonstrate toxicity of LCLipo-HHT. Compared with clinical HHT injection dosage, LCLipo-HHT indicated no vascular irritation, good hemocompatibility, as well as much better safety. Therefore, the prepared LCLipo-HHT can be used as a promising anticancer formulation for antileukemic therapy in the future.     

Stripe domain analysis of alkanethiol and alkynethiol monolayers self-assembled on the surfaces of gold grains

The self-assembled monolayers (SAMs) of alkanethiols such as 1-dodecanethiol (DDT) on the surface of polycrystalline gold grain on quartz crystal microbalance (QCM) at room temperature and alkynethiols such as phenylethynyl thiol (PET) on the surface of Au(111)/mica under − 65 °C have been fabricated. A multimode scanning probe microscope (SPM) investigation for the first time reveals the formation of stripe domain of DDT SAMs together with roundish domain. This feature was not caused by an annealing treatment but might be induced by coexistence of a few different facets and reconstruction of the surface on the grain. The stripe domain of PET SAMs could also be found on the surface of the grain, which was within the substrate of the gold/mica. It shows that the feature of the stripe domain for organothiol monolayers self-assembled on gold grain surfaces possesses a certain generality. Furthermore, the arrangement of organothiol stripe domain can be well understood from the interpretation of the relationship between the stripe width and width direction, molecule interval distance, molecule length and tilt angles of the thiols.     

Air-stable ultrathin Cr3Te4 nanosheets with thickness-dependent magnetic biskyrmions

Two-dimensional (2D) materials with intrinsic magnetism have drawn intense interest for fundamental research and potential application in spintronics and valleytronics. Here we synthesized 2D Cr₃Te₄ nanosheets with controllable thickness by chemical vapor deposition approach. Reflection magnetic circular dichroism and magneto-transport measurements demonstrated that the Cr₃Te₄ nanosheets feature excellent environmental stability and have a thickness-dependent ferromagnetic behavior with a high Curie temperature of 165–235 K. Lorentz transmission electron microscopy studies revealed topologically nontrivial magnetic-spin states in the ultrathin Cr₃Te₄ nanosheets. The magnetic stripe domains in Cr₃Te₄ can transform into biskyrmion bubbles when an external magnetic field is applied perpendicularly to the nanosheet. The size and density of the biskyrmions can be tuned by the external applied magnetic field and thickness of the nanosheets, respectively. Our findings of topologically nontrivial magnetic-spin states in air-stable 2D magnets could promise new designs of magnetic memory storage, sensors, and spintronics.     

The surface modification of medical polyurethane to improve the hydrophilicity and lubricity: The effect of pretreatment

The medical polyurethane (PU) film was grafted with poly(acrylic acid) (PAA) to improve the hydrophilic and lubricious properties. The influences of pretreatment by ozone or potassium peroxydisulfate on themorphologies of PU films and grafting results were systematically investigated. The grafted PU films were characterized using attenuated total reflection Fourier transformed infrared spectroscopy (ATR‐FTIR), scanning electron microscopy (SEM), atomic force microscopy (AFM) and gel permeation chromatography (GPC). The hydrophilic and lubricious properties were evaluated by water contact angle and friction coefficient, respectively. The results showed that PAA could be grafted firmly on PU activated by both ozone and potassium peroxydisulfate, and the PAA‐grafted PU showed good hydrophilic and lubricious performance. More importantly, the PAA‐grafted PU films with the pretreatment of ozone were better in surface roughness, hydrophilicty and lubricity, compared to those with the pretreatment of potassium peroxydisulfate. Hence, surface ozonation could be a better choice for the pretreatment of medical polymer. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Adaptive iron-based magnetic nanomaterials of high performance for biomedical applications

With unique physicochemical properties and biological effects,magnetic nanomaterials(MNMs)play a crucial role in the biomedical field.In particular,magnetic iron oxide nanoparticles(MIONPs)are approved by the United States Food and Drug Administration(FDA)for clinical applications at present due to their low toxicity,biocompatibility,and biodegradability.Despite the unarguable effectiveness,massive space for improving such materials'performance still needs to be filled.Recently,many efforts have been devoted to improving the preparation methods based on the materials'biosafety.Besides,researchers have successfully.regulated the performance of magnetic nanoparticles(MNPs)by changing their sizes,morphologies,compositions;or by.aggregating as-synthesized MNPs in an orderly arrangement to meet various clinical requirements.The rise of cloud computing and artificial intelligence techniques provides novel ways for fast material characterization,automated data analysis,and mechanism demonstration.In this review,we summarized the studies that focused on the preparation routes and performance regulations of high-quality MNPs,and their special properties applied in biomedical detection,diagnosis,and treatment.At the same time,the future.development of MNMs was also discussed.     

Effects of Proteins from Culture Medium on Surface Property of Silanes- Functionalized Magnetic Nanoparticles

Monodisperse magnetic nanoparticles (MNPs) were synthesized by thermal decomposition of iron-oleate and functionalized with silanes bearing various functional groups such as amino group (NH₂), short-chain poly(ethylene glycol) (PEG), and carboxylic group (COOH). Then, silanes-functionalized magnetic nanoparticles (silanes-MNPs) were incubated in cell culture medium plus fetal calf serum to investigate the effects of proteins from culture medium on surface property of MNPs. Zeta potential measurements showed that although surface charges of silanes-MNPs were different, they exhibited negative charges at neutral pH and approximate isoelectric points after they were incubated in cell culture medium. The reason was that silanes-MNPs could easily adsorb proteins from culture medium via non-covalent binding, resulting in the formation of protein-silanes-MNPs conjugates. Moreover, silanes-MNPs with various functional groups had different adsorption capacity to proteins, as confirmed by Coomassie blue fast staining method. The in vitro cell experiments showed that protein-silanes-MNPs had higher cellular uptake by cancer cells than silanes-MNPs.     

Facile synthesis of networked gold nanowires based on the redox characters of aniline

Metal nanowires are often used in the study of electron transport properties, electronic device technology and many other fields. We have reported a facile while effecting an approach to networked gold nanowires by taking advantage of the redox characters of aniline at different pH values. The effects of different synthetic parameters, such as mole ratio of HAuCl₄ to aniline, pH value, on the shape and size of the final gold products are investigated. Based on the experimental data, a possible growth mechanism is also proposed. This work probably contributes to not only the fundamental research of shape-controlled nanostructures but also new methods of producing nanoscaled metal wires for nanodevice study.     

Computer simulation of the inclusion of hydrophobic nanoparticles into a lipid bilayer

Understanding influences of nanoparticle (NP) inclusions into a lipid membrane is important in a variety of areas including biological systems and pharmacology. However, the inhomogeneous nature of lipid bilayers on a nanometer length scale complicates experimental studies of membrane inclusion. Here, we have performed coarse-grained molecular dynamics simulations aimed at the influence of the hydrophobic NPs inclusion into the lipid bilayer (dipalmitoylphosphatidylcholine or DPPC bilayer). The immersion of a nanoparticle into the hydrophobic core of the membrane has been observed in the simulation. To gain more insight in the inclusion, we have obtained free energy, entropy, enthalpy, and heat capacity profiles based on umbrella sampling calculations. These results show the inclusion process is driven by the co-action of entropy and enthalpy, which is consistent with some experimental and theoretical observations. Those results could be applied in the design of specific nanoparticles for various biomedical applications.     

A novel approach to the dynamic analysis of highly deformable bodies

A method using element-fixed moving reference frames is introduced to compute the behavior of highly deformable bodies undergoing large and fast rotations. The use of reference frames attached to each finite element allows the correct computation of overall large deformations and the characterization of rigid-flexible coordinate coupling through the systematic incorporation of higher-order kinematic terms and time derivatives of coordinate transformation matrices. The approach is applied to planar rotating Bernoulli beams of various flexural rigidities and the results are compared to those obtained by other methods and ABAQUS, a nonlinear finite element package. The results indicate excellent agreement with published data and superior efficiency of computation.