Hydrogel-supported neural cell cultures are more in vivo-relevant compared to monolayers formed on glass or plastic substrates. However, there is a lack of synthetic microenvironment available for obtaining standardized and easily reproducible cultures characterized by tissue-mimicking cell composition, cell–cell interactions, and functional networks. Synthetic peptides representing the biological properties of the extracellular matrix (ECM) proteins have been reported to promote the adhesion-driven differentiation and functional maturation of neural cells. Thus, such peptides can serve as building blocks for engineering a standardized, all-synthetic environment. In this study, we have compared the effect of two chemically crosslinked hydrogel compositions on primary cerebellar cells: collagen-like peptide (CLP), and CLP with an integrin-binding motif arginine-glycine-aspartate (CLP-RGD), both conjugated to polyethylene glycol molecular templates (PEG-CLP and PEG-CLP-RGD, respectively) and fabricated as self-supporting membranes. Both compositions promoted a spontaneous organization of primary cerebellar cells into tissue-like clusters with fast-rising Ca2+ signals in soma, reflecting action potential generation. Notably, neurons on PEG-CLP-RGD had more neurites and better synaptic efficiency compared to PEG-CLP. For comparison, poly-L-lysine-coated glass and plastic surfaces did not induce formation of such spontaneously active networks. Additionally, contrary to the hydrogel membranes, glass substrates functionalized with PEG-CLP and PEG-CLP-RGD did not sufficiently support cell attachment and, subsequently, did not promote functional cluster formation. These results indicate that not only chemical composition but also the hydrogel structure and viscoelasticity are essential for bioactive signaling. The synthetic strategy based on ECM-mimicking, multifunctional blocks in registry with chemical crosslinking for obtaining tissue-like mechanical properties is promising for the development of fast and well standardized functional in vitro neural models and new regenerative therapies.
An efficient procedure for chemical initiator-free, in situ synthesis of a functional polyethylene glycol methacrylate (PEG MA) hydrogel on regular glass substrates is reported. It is demonstrated that self-initiated photografting and photopolymerization driven by UV irradiation can yield tens of nanometer-thick coatings of carboxy-functionalized PEG MA on the aldehyde-terminated borosilicate glass surface. The most efficient formulation for hydrogel synthesis contained methyl methacrylic acid (MAA), 2-hydroxyethyl methacrylate (HEMA), and PEG methacrylate (PEG10MA) monomers (1:1:1). The resulting HEMA/PEG10MA/MAA (HPMAA) coatings had a defined thickness in the range from 11 to 50 nm. The physicochemical properties of the synthesized HPMAA coatings were analyzed by combining water contact angle measurements, stylus profilometry, imaging null ellipsometry, and atomic force microscopy (AFM). The latter technique was employed in the quantitative imaging mode not only for direct probing of the surface topography but also for swelling behavior characterization in the pH range from 4.5 to 8.0. The estimated high swelling ratios of the HPMAA hydrogel (up to 3.2) together with its good stability and resistance to nonspecific protein binding were advantageous in extracellular matrix mimetics via patterning of fibronectin (FN) at a resolution close to 200 nm. It was shown that the fabricated FN micropatterns on HPMAA were equally suitable for single-cell arraying, as well as controlled cell culture lasting at least for 96 h.
Though the issue of product country of origin has been researched by numerous researchers, due to globalization, currently consumers have more problems perceiving the country of origin than ever before. This brings marketing specialists back to the discussion of the topic once again, with emphasis on a distinction between the country of manufacturing origin and the country of brand origin. The impact of country of manufacturing and country of brand image varies from country to country under the influence of numerous impact factors, often summarized within a culture or subcultures. One type of such subcultures could be formed by immigrants, whose perceptions might include aspects of their home country combined with those of the host country. The main purpose of this paper was to evaluate the attitudes of Lithuanians who live in Lithuania (as a country of an emerging economy) and those of emigrants living in selected countries (Ireland, the United Kingdom and Finland) with regard to the importance of country of origin. Three brands were selected for the research – Panasonic, LG and BEKO, and three different cases were presented to the respondents. First, both the brand name (Panasonic) and the manufacturing country (the United Kingdom) were associated with a developed country. In the second case, country of brand origin (LG) was identified as a developed country while country of manufacture represented an emerging economy (Poland). Finally, an emerging economy of the country of brand origin (BEKO) and an emerging economy of the country of manufacturing (Turkey) were dealt with.Findings provide evidence that, in general, more developed countries had a better image as countries – manufacturers of TV sets than less developed countries (emerging economies). Analysis of opinions about country of brand origin revealed that brands from developed countries were evaluated better than those from emerging economies. In addition, analysis showed that respondents who live in an emerging economy have more positive attitude towards the surveyed brands compared with Lithuanian emigrants to developed countries. Finally, strong correlation was found between the evaluation of a brand and evaluation of the country of brand origin, while there was no correlation between evaluation of a brand and evaluation of country of manufacturing.
Dilated cardiomyopathy (DCM) is the most common type of nonischemic cardiomyopathy characterized by left ventricular or biventricular dilation and impaired contraction leading to heart failure and even patients’ death. Therefore, it is important to search for new cardiac tissue regenerating tools. Human mesenchymal stem/stromal cells (hmMSCs) were isolated from post-surgery healthy and DCM myocardial biopsies and their differentiation to the cardiomyogenic direction has been investigated in vitro. Dilated hmMSCs were slightly bigger in size, grew slower, but had almost the same levels of MSC-typical surface markers as healthy hmMSCs. Histone deacetylase (HDAC) activity in dilated hmMSCs was 1.5-fold higher than in healthy ones, which was suppressed by class I and II HDAC inhibitor suberoylanilide hydroxamic acid (SAHA) showing activation of cardiomyogenic differentiation-related genes alpha-cardiac actin (ACTC1) and cardiac troponin T (TNNT2). Both types of hmMSCs cultivated on collagen I hydrogels with hyaluronic acid (HA) or 2-methacryloyloxyethyl phosphorylcholine (MPC) and exposed to SAHA significantly downregulated focal adhesion kinase (PTK2) and activated ACTC1 and TNNT2. Longitudinal cultivation of dilated hmMSC also upregulated alpha-cardiac actin. Thus, HDAC inhibitor SAHA, in combination with collagen I-based hydrogels, can tilt the dilated myocardium hmMSC toward cardiomyogenic direction in vitro with further possible therapeutic application in vivo.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.