Novel Biologically Inspired Collagen Nanofibers Reconstituted by Electrospinning Method

The possibility to prepare bioinspired collagen nanofibers by electrospinning from aqueous suspension of telopeptide-free collagen molecules avoiding both organic solvents and blends with any synthetic and natural polymers has been investigated. The results have highlighted the need for a basic atmosphere between the needle and the ground collector in order to increase the environmental pH during the collagen molecules self-assembly along the electrostatic force lines. Morphological, spectroscopic and calorimetric analyses carried out on the electrospun collagen nanofibers have opened the possibility to take advantage of this new approach in order to prepare an ideal biomimetic reinforcing component of new biomedical and surgical biomaterials.     

Silk Fibroin-Coated Liposomes as Biomimetic Nanocarrier for Long-Term Release Delivery System in Cancer Therapy

Despite much progress in cancer therapy, conventional chemotherapy can cause poor biodistribution and adverse side-effects on healthy cells. Currently, various strategies are being developed for an effective chemotherapy delivery system. Silk fibroin (SF) is a natural protein used in a wide range of biomedical applications including cancer therapy due to its biocompatibility, biodegradability, and unique mechanical properties. In this study, SF-coated liposomes (SF-LPs) were prepared as a biomimetic drug carrier. Physicochemical properties of SF-LPs were characterized by Fourier-transform infrared spectroscopy (FTIR), dynamic light scattering, zeta potential measurement, and transmission electron microscopy (TEM). In vitro release of SF-LPs loaded with doxorubicin (DOX-SF-LPs) was evaluated over 21 days. Anticancer activity of DOX-SF-LPs was determined against MCF-7 and MDA-MB231 cells using the MTT assay. SF-LPs containing 1% SF exhibited favorable characteristics as a drug carrier. SF coating modified the kinetics of drug release and reduced the cytotoxic effect against L929 fibroblasts as compared to the uncoated liposomes containing cationic lipid. DOX-SF-LPs showed anticancer activity against breast cancer cells after 48 h or 72 h at 20 μM of DOX. This approach provides a potential platform of long-term release that combines biocompatible SF and phospholipids for cancer therapy, achieving efficient drug delivery and reducing side-effects.     

Breath Figures of Nanoscale Bricks: A Universal Method for Creating Hierarchic Porous Materials from Inorganic Nanoparticles Stabilized with Mussel‐Inspired Copolymers

High‐performance catalysts and photovoltaics are required for building an environmentally sustainable society. Because catalytic and photovoltaic reactions occur at the interfaces between reactants and surfaces, the chemical, physical, and structural properties of interfaces have been the focus of much research. To improve the performance of these materials further, inorganic porous materials with hierarchic porous architectures have been fabricated. The breath figure technique allows preparing porous films by using water droplets as templates. In this study, a valuable preparation method for hierarchic porous inorganic materials is shown. Hierarchic porous materials are prepared from surface‐coated inorganic nanoparticles with amphiphilic copolymers having catechol moieties followed by sintering. Micron‐scale pores are prepared by using water droplets as templates, and nanoscale pores are formed between the nanoparticles. The fabrication method allows the preparation of hierarchic porous films from inorganic nanoparticles of various shapes and materials.

     

Modified Hyaluronan Hydrogels Support the Maintenance of Mouse Embryonic Stem Cells and Human Induced Pluripotent Stem Cells

These studies provide evidence for the ability of a commercially available, defined, hyaluronan‐gelatin hydrogel, HyStem‐C?, to maintain both mouse embryonic stem cells (mESCs) and human induced pluripotent stem cells (hiPSCs) in culture while retaining their growth and pluripotent characteristics. Growth curve and doubling time analysis show that mESCs and hiPSCs grow at similar rates on HyStem‐C? hydrogels and mouse embryonic fibroblasts and Matrigel?, respectively. Immunocytochemistry, flow cytometry, gene expression and karyotyping reveal that both human and murine pluripotent cells retain a high level of pluripotency on the hydrogels after multiple passages. The addition of fibronectin to HyStem‐C? enabled the attachment of hiPSCs in a xeno‐free, fully defined medium.

     

以蛋清蛋白及半透膜为模板调控碳酸钙的仿生合成

依据生物矿化的基本原理,以蛋清蛋白为基质,透析袋组成隔室,在仿生条件下,诱导碳酸钙的合成。扫描电子显微镜和红外测试结果表明,半透膜和蛋白质虽然直接影响碳酸钙的形貌,但在半透膜和蛋清蛋白调控下生成的碳酸钙均为球霰石型晶体。实验结果表明,半透膜的选择性透过功能不仅限制了蛋白质的自由移动,同时也限制了蛋白质和Ca2+配合物的自由移动,从而为制备特殊形貌的碳酸钙固体提供了基础。     

One-pot aqueous solution syntheses of iron oxide nanostructures with controlled crystal phases through a microbial-mineralization-inspired approach

Iron-oxidizing bacteria produce trivalent iron oxides with the controlled crystal phases outside of their cells. Herein we have synthesized iron oxides with controlled oxidation states and crystal phases through a microbial-mineralization-inspired approach in an aqueous solution at low temperature. Trivalent iron oxides, such as lepidocrocite, ferrihydrite, goethite, and hematite, are selectively obtained from an aqueous solution containing divalent iron ions below 90 °C. The presence of a chelating agent facilitates the control of the oxidation states through the ligand-controlled approach because the precipitation of the divalent iron species is inhibited by the complexation between divalent iron ion and a chelating agent. The control of the crystal phases is achieved by the tuning of the synthetic conditions, such as the initial pH, the concentration of a chelating agent, and the reaction temperature. Furthermore, the resultant iron oxides have hierarchically organized structures consisting of nanoscale objects. The microbial-mineralization-inspired approach by using a chelating agent has potentials for the further morphological control of iron oxides and the further application to aqueous-solution syntheses of other metal oxides.     

Lessons from nature: biomimetic subwavelength structures for high‐performance optics

In nature, optical structures in the subwavelength range have been evolved over millions of years. For example, in the form of ‘moth‐eye’ structures they show a strong anti‐reflective effect on the compound eyes of night‐active insects and therefore offer a successful protection over predators. In this contribution the advantages and challenges to transfer this natural concept of subwavelength structured optical interfaces to high‐end optical systems are discussed. Here, in comparison to alternative conventional multilayer systems, the bioinspired anti‐reflective structures offer a wide wavelength range and a broad angle dependency. Additionally, adhesion problems are reduced drastically. Simultaneously to the theoretical consideration of the best profile form of the subwavelength structures, appropriate realization technologies have been developed in recent years, where both top‐down and bottom‐up approaches have been investigated. Depending on the choice of the structuring technique, anti‐reflective subwavelength structures are applicable to a wide spectrum of optical elements ranging from micro‐optical components to aspheres for applications in imaging and also illumination setups of high‐end optical instruments.     

Synthesis, structures, and spectral properties of biomimetic azomethine metal chelates with chromophores CuN2S2, CuN2O2, and CuN2Se2. Crystal structure of bis[4-(benzyl)aldimino-3-methyl-1-phenyl-5-pyrazolothiolato]copper(II)

Copper(II) chelates of composition CuL₂ were synthesized based on 4-aminomethylene derivatives of 5-thiopyrazoles (LH). The complexes were studied by UV, IR, ESR, and EXAFS spectroscopy, magnetochemistry, and X-ray diffraction analysis. The coordination polyhedra in the complexes are pseudotetrahedra or octahedra of the types CuN₂S₂ or CuN₄S₂, respectively, which are distorted due to the Jahn—Teller effect. The UV and ESR spectra of copper chelates with a six-coordinate metallocycle formed by the N and S atoms of the azomethine ligand and the nitrogen atom of the quinoline substituent (R) of the C=N−R fragment are most similar to the spectra observed for metals involved in the active centers of natural metalloenzymes (“blue” copper proteins). Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1891–1896, November, 2000.     

Generation of Hierarchical Topologies from Photocrosslinkable,Particle‐Stabilized Emulsions

Summary: We describe a way to obtain biomimetic, hierarchical surface morphologies. In order to mimic natural surfaces more accurately such as lotus leaves and gecko feet, we employ a strategy that bears many of the attractive characteristics of natural materials synthesis. The system in question consists of a photocurable monomer and water. To this quasi‐two‐component system we add polymer latex spheres. The monomer–water interface is then manipulated according to the well‐established science of complex fluids. Drawing from the rich phase behavior of particle‐stabilized emulsions, we demonstrate the creation of complex biomimetic morphologies over many length scales. The resulting structures are then solidified by crosslinking the monomer with UV light.

Comparison of an AFM image of a PMMA colloidosome assembly with that of the textured surface of a superhydrophobic Hygoryza aristata leaf (inset).