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.

In present study microcapsules composed of synthetic (PSS and PAA) and biodegradable (DS and PAr) polyelectrolytes on calcium carbonate microparticles were obtained. The ultrastructural organization of biodegradable microcapsules was studied using transmission electron microscopy. The envelope of such capsules consisting of six polyelectrolyte layers is already well-formed, having the average thickness of 44 ± 3.0 nm, and their internal polyelectrolyte matrix is sparser compared to the synthetic microcapsules. Spectroscopy was employed to evaluate the efficiency of incorporation of FITC-labeled BSA into synthetic microcapsules by adsorption, depending on the number of polyelectrolyte layers. It was shown that the maximal amount of protein incorporated into the capsules with 6 or 7 polyelectrolyte layers (4 and 2 pg/capsule, correspondingly). As a result we conclude that, in comparison with co-precipitation, the use of adsorption allows to completely avoid the loss of protein upon encapsulation.

Due to an unfortunate turn of events, the first-and surnames of all authors were transposed in the original publication. The correct representation of the authors' names and their affiliations are listed in this erratum.The online version of the original article can be found at http://dx.doi.

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.