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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]

Summary: The use of polymeric carriers containing dispersed magnetic nanocrystalline particles has attracted considerable interest in the medical field. In this paper, we propose an innovative nanotechnological platform for cancer therapy, based on highly magnetized, biodegradable, and biocompatible polymeric nanoparticles. Alginate magnetic nanoparticles were prepared by our group by an efficient emulsion/reticulation technique and tested as drug delivery system. Here, we present a potential application that combines, in a single nanovector, efficient targeting, overcoming of bio-barriers, drug delivery, and physical disruption of tumor tissues. [Copyright &y& Elsevier]

Abstract: Nanoparticles engineered for biomedical applications are meant to be in contact with protein-rich physiological fluids. These proteins are usually adsorbed onto the nanoparticle's surface, forming a swaddling layer that has been described as a ‘protein corona’, the nature of which is expected to influence not only the physicochemical properties of the particles but also the internalization into a given cell type. We have investigated the process of protein adsorption onto different magnetic nanoparticles (MNPs) when immersed in cell culture medium, and how these changes affect the cellular uptake. The role of the MNPs surface charge has been assessed by synthesizing two colloids with the same hydrodynamic size and opposite surface charge: magnetite (Fe3O4) cores of 25–30 nm were in situ functionalized with (a) positive polyethyleneimine (PEI-MNPs) and (b) negative poly(acrylic acid) (PAA-MNPs). After few minutes of incubation in cell culture medium the wrapping of the MNPs by protein adsorption resulted in a 5-fold increase of the hydrodynamic size. After 24 h of incubation large MNP-protein aggregates with hydrodynamic sizes of ≈1500 nm (PAA-MNPs) and ≈3000 nm (PEI-MNPs) were observed, each one containing an estimated number of magnetic cores between 450 and 1000. These results are consistent with the formation of large protein-MNPs aggregate units having a ‘plum pudding’ structure of MNPs embedded into a protein network that results in a negative surface charge, irrespective of the MNP-core charge. In spite of the similar negative ζ-potential for both MNPs within cell culture, we demonstrated that PEI-MNPs are incorporated in much larger amounts than the PAA-MNPs units. Quantitative analysis showed that SH-SY5Y cells can incorporate 100% of the added PEI-MNPs up to ≈100 pg/cell, whereas for PAA-MNPs the uptake was less than 50%. The final cellular distribution showed also notable differences regarding partial attachment to the cell membrane. These results highlight the need to characterize the final properties of MNPs after protein adsorption in biological media, and demonstrate the impact of these properties on the internalization mechanisms in neural cells. [Copyright &y& Elsevier]