Наполнение импланта волокнистым наноматериалом обеспечивает уникальные возможности ускорения регенерации нерва

Numerous nanostructured synthetic scaffolds mimicking the architecture of the natural extracellular matrix (ECM) have been described, but the polymeric nanofibers comprising the scaffold were substantially thicker than the natural collagen nanofibers of neural ECM. Here, we report neuron growth on electrospun scaffolds of nylon-4,6 fibers with an average diameter of 60 nm, which closely matches the diameter of collagen nanofibers of neural ECM, and compare their properties with the scaffolds of thicker 300 nm nanofibers. Previously unmodified nylon was not regarded as an independent nanostructured matrix for guided growth of neural cells; however, it is particularly useful for ultrathin nanofiber production. We demonstrate that, while both types of fibers stimulate directed growth of neuronal processes, ultrathin fibers are more efficient in promoting and accelerating neurite elongation. Both types of scaffolds also improved synaptogenesis and the formation of connections between hippocampal neurons; however, the mechanisms of interaction of neurites with the scaffolds were substantially different. While ultrathin fibers formed numerous weak immature β1-integrin-positive focal contacts localized over the entire cell surface, scaffolds of submicron fibers formed β1-integrin focal adhesions only on the cell soma. This indicates that the scaffold nanotopology can influence focal adhesion assembly involving various integrin subunits. The fabricated nanostructured scaffolds demonstrated high stability and resistance to biodegradation, as well as absence of toxic compound release after 1 month of incubation with live cells in vitro. Our results demonstrate the high potential of this novel type of nanofibers for clinical application as substrates facilitating regeneration of nervous tissue.

https://doi.org/10.3390/nano11020516

3D models of brain organoids represent an innovative and promising tool in neuroscience studies. However, the process of neurosphere formation in vitro remains complicated and is not always very effective. This is largely due to the lack of growth factors, guidance cues, and scaffold structures commonly found in tissues. Here we present a new, simple, and efficient method for generating neurospheres using scaffolds composed of electrospun nylon fibers with a diameter of 40–180 nm, which makes them similar to the brain extracellular matrix (ECM) components. Several main advantages of the proposed method should be highlighted. The method is fast, and the biomaterial consumption is low. Also, the resulting neurospheres are attached to the scaffold nanofibers. This not only provides the experimental convenience but also suggests that the resulting organoid models can potentially demonstrate fundamentally new properties, being closer to the nervous tissue in vivo. We demonstrate the influence of the fibrous scaffold structure on the formation, morphology, and composition of neurospheres and confirm adequate functional activity of the cellular components of these spheroids. The proposed approach can be further used for drug screening, modeling of neurodevelopmental, neurodegenerative disorders, and, potentially, therapeutic tissue engineering.

The topological cues of fibrous scaffolds (in particular extracellular matrix (ECM)-mimetic nanofibers) have already proven to be a powerful tool for influencing neuronal morphology and behavior. Remote photothermal optical treatment provides additional opportunities for neuronal activity regulation. A combination of these approaches can provide “smart” 3D scaffolds for efficient axon guidance and neurite growth. In this study we propose two alternative approaches for obtaining biocompatible photothermal scaffolds: surface coating of nylon nanofibers with light-to-heat converting nanoparticles and nanoparticle incorporation inside the fibers. We have determined photoconversion efficiency of fibrous nanomaterials under near infrared (NIR) irradiation, as well as biocompatible photothermal treatment parameters. We also measured photo-induced intracellular heating upon contact of cells with a plasmonic surface. In the absence of NIR stimulation, our fibrous scaffolds with a fiber diameter of 100 nm induced an increase in the proportion of β3-tubulin positive cells, while thermal stimulation of neuroblastoma cells on nanoparticles-decorated scaffolds enhanced neurite outgrowth and promoted neuronal maturation. We demonstrate that contact guidance decorated fibers can stimulate directional growth of processes of differentiated neural cells. We studied the impact of nanoparticles on the surface of ECM-mimetic scaffolds on neurite elongation and axonal branching of rat hippocampal neurons, both as topographic cues and as local heat sources. We show that decorating the surface of nanofibers with nanoparticles does not affect the orientation of neurites, but leads to strong branching, an increase in the number of neurites per cell, and neurite elongation, which is independent of NIR stimulation. The effect of photothermal stimulation is most pronounced when cultivating neurons on nanofibers with incorporated nanoparticles, as compared to nanoparticle-coated fibers. The resulting light-to-heat converting 3D materials can be used as tools for controlled photothermal neuromodulation and as “smart” materials for reconstructive neurosurgery.