A microstructured composite material made of collagen hydrogel (matrix) and silk fibroin microfibers (randomly oriented reinforcing fibers) is investigated in order to conjugate the mechanical resistance of fibroin with the suitable biological performance of collagen to design new scaffolds for vascular tissue engineering. Results show that fibroin microfibers and collagen fibrils have suitable interfacial adhesion, and the scaffold exhibits improved mechanical properties if compared with a pure collagen hydrogel. Furthermore, the overall biological performance is improved.
The conversion of processed discarded material into valuable by‐products and alternative specialty materials has been identified as a timely challenge for food research and development associated with numerous applications of chitinous products. Chitin, chitosan, calcareous chitin, and chitosan, N‐acetylated chitosan, N‐methylene phosphonic chitosan (NMPC), and N‐lauryl‐N‐methylene phosphonic chitosan (LMPC) are being studied as a result of their broad range of food applications. These biopolymers offer a wide range of unique applications including formation of biodegradable films, immobilization of enzymes, preservation of foods from microbial deterioration, as additives (clarification and deacidification of fruits and beverages, emulsifier agents, thickening and stabilizing agents, color stabilization), and dietary supplements. This review summarizes some of the most important developments in this field. 相似文献
Summary: A novel method for the encapsulation of biomacromolecules, such as nucleic acids and proteins, into polyelectrolyte microcapsules is described. Fluorescence‐labelled double‐stranded DNA and human serum albumin (HSA) are used as model substances for encapsulation in hollow microcapsules templated on human erythrocytes. The encapsulation procedure involves an intermediate drying step. The accumulation of DNA and HSA in the capsules is observed by confocal laser scanning microscopy, UV spectroscopy, and fluorimetry. The mechanism of encapsulation is discussed.
Confocal fluorescence microscopy images of encapsulated TRITC‐HSA (left) and dsDNA (right). Inserts demonstrate fluorescence profiles for both compounds. 相似文献
Two new HA derivatives bearing carborane rings were synthesized by click chemistry. The optimal conditions were assessed for the preparation of biocompatible boron carriers, potentially suitable for application in BNCT and capable of targeting the CD44 antigen. The new polymeric samples were characterized by means of NMR-spectroscopy techniques that gave degrees of 17 and 8% for HAAACB and HapACB, respectively. Both HAAACB and HApACB turned out to be nontoxic for colorectal, ovarian and bladder tumor cell lines, to disclose a specific interaction with the CD44 antigen as the native hyaluronan moiety, and to deliver boron-atom concentrations largely sufficient for BNCT therapy when accumulated in cancer cells. 相似文献
The harmful Esca disease in vine plants caused by wood‐inhabiting fungi including Phaeomoniella chlamydospora (Pch) is spreading all across the world. This disease leads to poor vine crops and a slow decline or to a sudden dieback of the vine plants. The pruning wounds of vine plants are the main entry point for Pch. While model experiments with aerosol particles recommend electrospun nonwovens as a suitable barrier to block Pch, tests with living spores show clearly that only electrospun fibrous nonwovens do not prevent Pch invasion. However it is found, that with antifungal additives electrospun nonwovens could be applied successfully for blocking of Pch to infect the substrate. Thereby, a highly useful concept for the protection of vine plants against Esca disease is provided which could also serve as a concept for related plant diseases.
The effect of doping P3OT with ferric chloride on the attachment and proliferation of MC3T3‐E1 osteoblasts is reported. Cell density and area correlated strongly with doping concentration: cells were larger and exhibited better spreading as doping increased. Cells cultured on undoped P3OT showed a decrease in proliferation between 24 and 48 h followed by a recovery after 72 h. However, this trend diminished with increasing doping concentration, and disappeared completely at the highest dopant level investigated. Analysis of cell‐cell spatial distributions suggested that contact inhibition of proliferation occurred similarly on both undoped and doped P3OT. From these results, FeCl3‐doping had no significant deleterious effect on attachment or proliferation of osteoblasts in vitro.
Since the introduction of the general concept, field-flow fractionation (FFF) was developed to a complex of separation methods that differ by the fundamental processes underlying and accompanying the separation. In this review, the basic principles on which this separation methodology lies are presented, the most important methods and techniques applicable for analytical and preparative fractionations are described, the first approximation theoretical treatment of the separation processes is outlined, and typical applications for analytical and micropreparative purposes are demonstrated. The main goal is to show that FFF represents an interesting and competitive option of the separation methods applicable in analytical chemistry. The existence of some conflicting opinions concerning the theory as well as the experiments does not prohibit the analytical and preparative use of FFF. If not regarded only as a routine analytical tool, it should stimulate the research and development efforts. On the other hand, when used as an analytical tool, even if the approximate theoretical models are not fully supported by the experiments, the correct analytical result can be obtained from FFF (as well as from any other analytical separation method) by using a calibration procedure and an appropriate treatment and interpretation of the raw experimental data. 相似文献
New antimicrobial microfibrous electrospun mats from styrene/maleic anhydride copolymers were prepared. Two approaches were applied: (i) grafting of poly(propylene glycol) monoamine (Jeffamine® M‐600) on the mats followed by formation of complex with iodine; (ii) modification of the mats with amines of 8‐hydroxyquinoline or biguanide type with antimicrobial activity. Microbiological screening against S. aureus, E. coli and C. albicans revealed that both the formation of complex with iodine and the covalent attachment of 5‐amino‐8‐hydroxyquinoline or of chlorhexidine impart high antimicrobial activity to the mats. In addition, S. aureus bacteria did not adhere to modified mats.
Water‐soluble star‐like poly(vinyl alcohol)/C60 and poly{[poly(ethylene glycol) acrylate]‐co‐(vinyl acetate)}/C60 nanohybrids are prepared by grafting macroradicals onto C60 and are assessed as photosensitizers for photodynamic therapy. The photophysical and biological properties of both nanohybrids highlight key characteristics influencing their overall efficiency. The macromolecular structure (linear/graft) and nature (presence/absence of hydroxyl groups) of the polymeric arms respectively impact the photodynamic activity and the stealthiness of the nanohybrids. The advantages of both nanohybrids are encountered in a third one, poly[(N‐vinylpyrrolidone)‐co‐(vinyl acetate)]/C60, which has linear grafts without hydroxyl groups, and shows a better photodynamic activity.
In routine clinical procedures, blood transfusion is now suffering from the defects of the blood products, like cross-matching, short storage time and virus infection. Various blood substitutes have been designed by researchers through continual efforts. With recent progress in nanotechnology, new types of artificial red blood cells with cellular structure are available. This article aims to describe some artificial red blood cells which encapsulate or conjugate hemoglobin molecules through various approaches, especially the nanoscale self-assembly technique, to mitigate the adverse effects of free hemoglobin molecules. These types of artificial red blood cell systems, which make use of biodegradable polymers as matrix materials, show advantages over the traditional types. 相似文献
By Monte Carlo simulations we provide insight into the isolated single‐ and double‐tethered (ST and DT) polymer chain attached to an impenetrable surface to elucidate open theoretical questions and guide future experiments investigating the impact of tethering on the genome packaging by concurrent visualisation of multiple loci along the chromosome(s). In the models, either one or both ends (at a grafting distance d) are fixed or the ST and DT chain are “annealed” by permitting the anchor(s) to diffuse laterally along the surface. We analyse chain self‐entanglement, intrachain segment correlations, the relationship between mean square physical distance and corresponding contour length and provide the first report on the diffusion behaviour.
An elastin-mimetic polypeptide, (EMM)(7), with the amino-acid sequence GRDPSS [VPGVG VPGKG VPGVG VPGVG VPGEG VPGIG](7) was used for chemical conjugation of various integrin ligands (RGD peptides) to prepare bioactive hydrogels. The chemical approach involved (1) chemical protection of lysine residues with Fmoc or Boc groups, (2) chemical ligation of a protected linear or cyclic RGD ligand, with or without a hexanoic-acid spacer to the glutamic acid residue, (3) deprotection of the lysine functionalities and the RGD moieties and (4) cross-linking to form a bioactive hydrogel. (1)H NMR spectroscopy was used to quantify the multiple steps in the reaction. The chemical protection was found to be between 65 and 93% for Fmoc and Boc, respectively. The ligands studied included linear RGD cell-binding [H-FGRGDS-OH (1-l-RGD), H-Ahx--FGRGDS-OH (2-Ahx-FGRGDS) and a cyclic -H(2)N-(CH(2))(6)COHN-cyclo(-RGDfK-) (H-Ahx-c(-RGDfK-)) peptide also with a hexanoic-acid spacer. Cell adhesion with mouse osteoblast cells was dependent on the ligand type, ligand density and the use of a spacer. 相似文献