Nano LIFE

Hybrid graphene oxide (GO) with metal ions have become very promising for many applications including catalyst, thermal conductive paper, magnetic devices, energy storage and electronics. In this paper, GO was mixed with trivalent rare earth ions, LaCl₃ to prepare GO/LaCl₃ hybrid composites. The GO/LaCl₃ hybrid composites were tunable by controlling the ratio of LaCl₃ to GO. The interaction between GO and LaCl₃ includes the coordination of La³⁺ with carboxyl groups at the edges of GO, the coordination of La³⁺ with epoxides and hydroxyls, and the electrostatic force between La³⁺ and aromatic bonds of GO. The La³⁺ preferred the coordination with the oxygen-containing groups of GO sheets first. However, the electrostatic absorption of La³⁺ was the main factor that controls the deposit of GO/LaCl₃ composites. The GO/LaCl₃ hybrid structures were also investigated.

The water-soluble fluorescent carbon nanomaterials with low toxicity and high biocompatibility are considered as promising materials for biomedical and sensor applications. Here, we report that a nanosensor system has been developed to simultaneously detect two valence states of iron (Fe²⁺ and/or Fe³⁺) in aqueous solution based on fluorescent carbon nanoparticles (FCNs). The nanosensor has high selectivity and sensitivity with a limit of detection (LOD) of 5 μM, which is equivalent to 0.3 mg/L (5.36 μM) of iron in drinking water by United States Environment Protection Agency (US-EPA). Furthermore, a distinguishable color change of solution, from pale yellow to red-brown, can be observed as iron concentration reaching 40 μM, which provides way for fast, visible detection of irons.

Various docetaxel (DTX)-loaded nanoparticle delivery systems have been designed to enhance the solubility and pharmacological effects of DTX. However, the toxicity changes of these nano-modified DTX (nano-DTX) are not yet clear enough. Herein, to compare the reproductive toxicity between conventional DTX and nano-DTX, we performed sperm toxicity test in mice, and fertility and early embryo-fetal developmental toxicity test in rats. It was found that DTX severely repressed spermatogenesis and sperm motility, and dramatically increased sperm abnormality in mice and rats. Moreover, DTX significantly decreased copulation, conception and fertility indexes in rats, and no positive pregnant female rat was obtained after treatment with DTX. However, nano-DTX significantly reduced DTX-induced toxicity to sperm. Most importantly, nano-DTX obviously converted DTX-induced fertility and early embryo-fetal developmental toxicity. Furthermore, organ weights and histopathology examination revealed DTX, but not nano-DTX, significantly decreased testis and epididymis weights, and induced obvious histopathological atrophy of testes and epididymides in rats. Further studies indicated that changed activity of lactate dehydrogenase C4 (LDH-C4) in rodents testes was mainly responsible for the above observations. These results strongly support the idea that DTX-loaded nanoformulations have the potential to overcome the reproductive toxicity of DTX.

The surface functionalization of poly(lactide-co-glycolide) (PLGA) nanoparticles (NPs) with various proteolytic enzymes (i.e., trypsin, papain, bromelain) via a two-step carbodiimide coupling method is presented. Depending on the initial Enzyme:NPs ratio, enzyme loadings up to 4.0 wt.%, 4.4 wt.% and 5.34 wt.% were achieved for trypsin, papain and bromelain, respectively. All three conjugated enzymes partially maintained their enzymatic activity after their coupling reaction with the NPs. NPs functionalized with papain and bromelain exhibited a three-fold higher permeability in porcine intestinal mucus compared to nonfunctionalized NPs whereas those conjugated with trypsin showed an almost two-fold higher permeability value. Measurements of the diffusion rates of intestinal mucin, using a nuclear magnetic resonance (NMR) technique, further confirmed these observations, as the enzyme-functionalized NPs were proven to be capable of disrupting the mucin gel structure. According to the reported results, the coupling of proteolytic enzymes to the PLGA NPs' surface largely increases the NPs mucus permeability, thus making it a potentially important mucus permeation strategy.

Nanocrystalline celluloses (NCCs) were separated from four commercial microcrystalline celluloses (MCCs) by an acid hydrolysis–sonication treatment. Transmission electron microscopy (TEM), atomic force microscopy (AFM), Fourier transform infrared (FTIR) spectrum, X-ray diffraction (XRD) and thermogravimetric analysis (TGA) were conducted to investigate the NCCs. MCCs with different morphologies and particle sizes showed different aggregation degrees. The aggregation of MCCs followed the order MCC1 > MCC3 > MCC2 > MCC4, which is the same order of the heights of the resulting NCCs. The best uniformity and thermal stability were characterized for NCC3, which was produced by MCC3 with smallest original particle size and good dispersity among the four MCCs. This result suggests that both the original particle size and dispersity of MCCs had significant effects on separated NCCs.

Zn_0.5Co_0.5O solid solution materials have been extensively studied for possible spintronic applications, however, there are only a few reports using Zn_0.5Co_0.5O nanostructures for energy storage. Here, we report the preparation of Zn_0.5Co_0.5O nanoparticles with the average particle size 10 nm and their application as anode material for rechargeable Li-ion batteries (LIBs). Electrochemical measurements demonstrate that the Zn_0.5Co_0.5O solid solution nanoparticles deliver a stable reversible capacity of 309 mA h g^-1 up to 250 cycles at 1 C rate. These results show higher-rate capability and better cycle durability compared with those of the reported ZnO or ZnO-based anodes.

Over the last two decades, hundreds of cell penetrating peptides (CPPs) have been intensively developed as drug and nucleic acid delivery vectors. In many cases, however, the efficient delivery of exogenous bioactive molecules through the plasma membrane to their targets remains a tremendous challenging issue. CPPs have attracted tremendous research interest as efficient cellular delivery vehicles due to their intrinsic ability to enter cells and mediate uptake of a wide range of macromolecular cargos, such as proteins, peptides, nucleic acids, drugs and nanoparticle carriers. This review presents and discusses the current perspectives of CPP-mediated siRNA delivery system. We focus on the CPP-mediated siRNA delivery approaches, and particular emphasis is placed on the strategies for the advantages and disadvantages for each delivery approach. Lastly, the cellular uptake mechanisms of CPPs and the specific challenges associated with each delivery system of siRNAs are discussed.

Exosomes were discovered more than 30 years ago. Only recently has their importance been recognized for intercellular communication. Exosomes, with their size ranging from 30 nm to 100 nm, are lipid bilayer nanoparticles and secreted by many different types of cells with versatile functions. Exosomes contain macromolecules and exist in various body fluids, including blood, urine, milk and ascites fluid. Due to their specific property, exosomes are very promising in the fields of disease diagnosis and therapy. Nanotechnology is a great tool that will be helpful in basic research and the application of exosomes. Here, we briefly review the function and potential use of exosomes in nanomedicine.

The mechanism of gene delivery and expression is one of the most important concerns raised by the development of gene delivery methods. Limited investigation is performed on how magnetic nanoparticles combine with DNA and deliver gene into mammalian cells. In this context, polyethyleneimine (PEI) coated iron oxide magnetic nanoparticles (MNPs) were used as gene carriers for binding and condensing with plasmid DNA expressing enhanced green fluorescent protein (EGFP). The morphology and structure of MNP–DNA complexes were characterized by transmission electron microscopy (TEM) and atomic force microscopy (AFM). We evidenced that large amounts of DNA wrapped around the surface of MNPs and that the MNPs were physically entrapped by the DNA arranged both horizontally and vertically. EGFP gene was successfully expressed under mediation of an external magnetic field which is necessary to efficiently target EGFP gene to the cells. Fluorescence from EGFP was separately detected in the cell cytoplasm and cell nucleus.

A graphene and carbon nanotube (CNT) array composite was synthesized by chemical vapor deposition (CVD) and chemically treated after synthesis, yielding a novel corrugated structure, visually similar to a mushroom gill. This binder-free hybrid material was used to make an electrode that may find application in energy storage devices, such as supercapacitors. The electrode performance of the corrugated graphene/CNT array composite (CGCC) was compared to that of commercial glassy carbon. The results of the comparison are presented here, along with suggestions for further development of the CGCC electrode.

Li-based rechargeable batteries are becoming popular power sources for biomedical devices and healthcare equipment. In nanoscale, lithium bonds may associate with intermolecular noncovalent interactions when Li atoms are shared by adjacent atoms inside rechargeable Li batteries. Theoretical study of lithium boding interactions thus is of paramount importance for a better understanding of the working mechanisms and designing high-efficient electrode–electrolyte interfaces from nanolevel for Li-based batteries. In this study, we used state-of-the-art theoretical methods, with inclusion of density functional theory/symmetry-adapted perturbation theory (DFT/SAPT), density functional reactivity theory (DFRT) and energy decomposition analysis (EDA), to delve into the nature of lithium bonding interactions. Our results showed that B3LYP outperforms all other functionals under consideration in the conventional supramolecular scheme, indicating that the formation of a lithium bond is not dispersion-driven. The calculated PBE0/SAPT and B3LYP/EDA data are consistent with each other, unravelling that the lithium bond is mainly of an electrostatically driven nature. Both steric hindrance and exchange-correlation potentials also make important contributions when two-variable fitting is considered. These results provide new sight in understanding lithium atom interactions for potential lithium-based batteries applications.