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Abstract The 3-D spatial and mechanical features of nano-topography can create alternative environments, which influence cellular response. In this paper, murine fibroblast cells were grown on surfaces characterized by protruding nanotubes. Cells cultured on such nano-structured surface exhibit stronger cellular adhesion compared to control groups, but despite the fact that stronger adhesion is generally believed to promote cell cycle progression, the time cells spend in G1 phase is doubled. This apparent contradiction is solved by confocal microscopy analysis, which shows that the nano-topography inhibits actin stress fiber formation. In turn, this impairs RhoA activation, which is required to suppress the inhibition of cell cycle progression imposed by p21/p27. This finding suggests that the generation of stress fibers, required to impose the homeostatic intracellular tension, rather than cell adhesion/spreading is the limiting factor for cell cycle progression. Indeed, nano-topography could represent a unique tool to inhibit proliferation in adherent well-spread cells. Graphical abstract Nano-topography influences cell mechanotransduction, by inhibiting stress fiber, formation. The lack of stress fibers blocks the transmission of out-to-inside force from, adhesion points to actin cytoskeleton and, consequently, the achievement of the critical, tensional homeostasis, which is required for RhoA activation and RhoA-dependent, suppression of p21 levels and cell cycle progression. Unlabelled Image [ABSTRACT FROM AUTHOR]

Abstract To improve the efficiency of pancreatic islet transplantation, we performed in-vitro and in-vivo experiments with isolated human pancreatic islets coated by multi-layer nano-encapsulation using differently charged polymers [chitosan and poly(sodium styrene sulfonate)] to obtain up to 9 layers. The islet coating (thickness: 104.2 ± 4.2 nm) was uniform, with ≥ 90% cell viability and well preserved beta- and alpha-cell ultrastructure. Nano-encapsulated islets maintained physiological glucose-stimulated insulin secretion by both static incubation and perifusion studies. Notably, palmitate- or cytokine-induced toxicity was significantly reduced in nano-coated islets. Xenotransplantation of nano-encapsulated islets under the kidney capsule of streptozotocin-induced C57Bl/6J diabetic mice allowed long term normal or near normal glycemia, associated with minimal infiltration of immune cell into the grafts, well preserved islet morphology and signs of re-vascularization. In summary, the multi-layer nano-encapsulation approach described in the present study provides a promising tool to effectively protect human islets both in-vitro and in-vivo conditions. Graphical Abstract Conformal coating of pancreatic islets with biocompatible polymers using layer-by-layer nano-encapsulation approach may represent a way to protect the transplanted islet cells without any immunosuppression. As an alternative to conventional macro- or micro-encapsulation methods, nano-encapsulation approach appears more advantageous as it provides decreased diffusion space, a robust response to physiological stimulation and reduced coating thickness. This versatile technique is likely to provide immune isolation of the transplanted islet cells with well preserved cell viability and function and warrants a successful outcome of prolonged engraftment in diabetic animals. Unlabelled Image [ABSTRACT FROM AUTHOR]

There is a growing body of evidence indicating the importance of physical stimuli for neuronal growth and development. Specifically, results from published experimental studies indicate that forces, when carefully controlled, can modulate neuronal regeneration. Here, we validate a non-invasive approach for physical guidance of nerve regeneration based on the synergic use of magnetic nanoparticles (MNPs) and magnetic fields (Ms). The concept is that the application of a tensile force to a neuronal cell can stimulate neurite initiation or axon elongation in the desired direction, the MNPs being used to generate this tensile force under the effect of a static external magnetic field providing the required directional orientation. In a neuron-like cell line, we have confirmed that MNPs direct the neurite outgrowth preferentially along the direction imposed by an external magnetic field, by inducing a net angle displacement (about 30°) of neurite direction. From the Clinical Editor This study validates that non-invasive approaches for physical guidance of nerve regeneration based on the synergic use of magnetic nanoparticles and magnetic fields are possible. The hypothesis was confirmed by observing preferential neurite outgrowth in a cell culture system along the direction imposed by an external magnetic field. [ABSTRACT FROM AUTHOR]

Abstract: Various in vivo biological models have been proposed for studying the interactions of nano-materials in biological systems. Unfortunately, the widely used small mammalian animal models (rodents) are costly and labor intensive and generate ethical issues and antagonism from the anti-vivisectionist movement. Recently, there has been increasing interest in the scientific community in the interactions between nano-materials and non-mammalian developmental organisms, which are now being recognized as valid models for the study of human disease. This review examines and discusses the biomedical applications and the interaction of nano-materials with embryonic systems, focusing on non-mammalian vertebrate models, such as chicken, zebrafish and Xenopus. From the Clinical Editor: Animal models are critical components of preclinical biomedical research. This review discusses the feasibility and potential applications of non-mammalian vertebral animals, such as zebrafish, xenopus, and chicken as animal models in nanomedicine research. [Copyright &y& Elsevier]

Abstract: There are conflicting data concerning the safety and biocompatibility of carbon nanotubes (CNTs). In some reports CNTs have been used for gene delivery without significant toxicity, whereas in others various cytotoxic effects were observed, including induction of intracellular reactive oxygen species (ROS), DNA damage, and apoptosis. Although it is clear that CNT production methods, purity, and functionalization treatments impact on biocompatibility, most of the published reports lack detailed characterization of the CNT samples used. We investigated the effect of various physicochemical features of multiwalled carbon nanotubes (MWCNTs) on toxicity and biocompatibility with cultured human neuroblastoma cells by using MTT, WST-1, Hoechst, and oxidative stress assays. In vitro experiments confirm that after 3 days of incubation with three different types of CNTs dispersed in Pluronic F127 solution, 0.01% cell viability is not affected and apoptosis and ROS are not induced in the SH-SY5Y cells. With prolonged cultures and continued propagation in the presence of MWCNTs, the loss of cell viability was minimal for pure MWCNTs (99% purity), but cell proliferation decreased significantly for 97% purity MWCNTs and acid-treated MWCNTs (97% purity, surface oxidation 8%); no intracellular ROS were detected. When the concentration of CNTs increases, purity and surface oxidation seem to affect cell viability (ED25 is 48, 34.4, and 18.4 μg/mL, respectively, for 99% purity MWCNTs, 97% purity MWCNTs, and acid-treated 97% purity MWCNTs. Our results indicate that concentrations of 5–10 μg/mL MWCNTs seem ideal for studies on the design and development of artificial MWCNT nanovectors for gene and drug therapy against cancer. From the Clinical Editor: With prolonged cultures, loss of cell viability was minimal for preparations with 99% purity, but significant adverse effects were detected with 97% purity and with acid-treated preparations. A concentrations of 5–10 μg/mL of MWCNTs seems ideal for gene and drug therapy against cancer. [Copyright &y& Elsevier]

Abstract: Carbon nanotubes (CNTs) are nanodevices with important potential applications in biomedicine such as drug and gene delivery. Brain diseases with no current therapy could be candidates for CNT-based therapies. Little is known about toxicity of CNTs and of their dispersion factors in the brain. Here we show that multiwall CNTs (MWCNTs) coated with Pluronic F127 (PF127) surfactant can be injected in the mouse cerebral cortex without causing degeneration of the neurons surrounding the site of injection. We also show that, contrary to previous reports on lack of PF127 toxicity on cultured cell lines, concentrations of PF127 as low as 0.01% can induce apoptosis of mouse primary cortical neurons in vitro within 24 hours. However, the presence of MWCNTs can avoid PF127-induced apoptosis. These results suggest that PF127-coated MWCNTs do not induce apoptosis of cortical neurons. Moreover, the presence of MWCNTs can reduce PF127 toxicity. [Copyright &y& Elsevier]

Abstract: We investigated the ability of cationic liposomes composed of 1,5-dihexadecyl N-arginyl-L-glutamate (Arg-Glu2C16) to carry nucleic acids into neuronal cells. Such liposomes have been shown to have a remarkable capacity for transfecting immortalized cell lines. Lipoplexes between the Arg-Glu2C16 liposomes and plasmid DNA encoding green fluorescent protein (GFP) were analyzed in terms of lipoplex formation, intracellular DNA trafficking, transfection efficiency, and cytotoxicity in neuronal SH-SY5Y cells. A maximum number of cells expressing GFP was obtained with lipoplexes at a lipid-to-DNA ratio of 15. With these lipoplexes, 16% of the cells were GFP-positive, which was approximately fourfold higher than the level obtained with a commercially available transfection reagent, Lipofectamine 2000. Furthermore, as a result of the low cytotoxicity of the Arg-Glu2C16 lipoplexes, the proportion of GFP-positive cells could be increased to 25% by increasing the concentration of lipoplexes that was applied to the cells. We have demonstrated that Arg-Glu2C16, as a model cationic amino acid–based lipid, has a high capability as a gene carrier, even for neuronal transfection. From the Clinical Editor: In this study, specific cationic liposomes were characterized as nucleic acid transfection agents for neuronal cells. A fourfold higher transfection rate with low cytotoxicity was reported compared to Lipofectamine 2000, a commercial reagent. The authors conclude that the studied cationic liposomes have a high capability as a gene carrier for neuronal transfection. This may become clinically significant in future gene therapy efforts of neuronal diseases. [Copyright &y& Elsevier]