Self‐assembled copper‐capillary alginate gel scaffolds with oligochitosan support embryonic stem cell growth

Abstract

Biomaterial scaffolds are fundamental components of strategies aimed at engineering a wide range of tissues. Scaffolds possessing uniform, oriented microtubular architectures could be ideal for multiple tissues, but are challenging to produce. Therefore, we developed hydrogel scaffolds possessing regular, tubular microstructures from self-assembled copper-capillary alginate gel (CCAG). To abrogate the rapid dissolution of CCAG in cell culture media, we treated it with oligochitosan and created a stable oligochitosan-CCAG (OCCAG) polyelectrolyte complex. Fourier transform infrared spectroscopy confirmed polyelectrolyte complexation between alginate and oligochitosan. OCCAG retained capillary morphology, shrank anisotropically in bulk, lost Cu(2+) ions, and maintained (71.9 +/- 5.65)% of its mass in cell culture media. Next, we seeded mouse embryonic stem (ES) cells within OCCAG scaffolds, and examined cell morphology and quantified cell growth and viability over four days. ES cells were guided to form cylindrical structures of staggered cells within scaffold capillaries. Analysis of the total cells recovered from the scaffolds revealed exponential cell growth (normalized to day 0) that was statistically similar to gelatinized-plate controls. OCCAG-cultured ES cell viability was also not significantly different from controls at day 4. CCAG-derived scaffolds can therefore serve as a unique platform for stem cell-based tissue engineering.

Controlled differentiation of stem cells

“…Alginate is derived from seaweed, and in presence of a divalent cation such as Ca 2+ , forms an ionically crosslinked hydrogel. Alginate-based hydrogels in combination with oligochitosan have been shown to support ES cells growth [152]. Additionally, alginate hydrogels demonstrated to be conducive for ES cell differentiation into hepatic lineage [153,154].…”

Texture analysis of TEM micrographs of alginate gels for cell microencapsulation

“…It is many years since TEM analysis of polysaccharides in solution and gel has been performed (Lamberti and Sefton, 1983;Lienemann et al, 1997), although images of polysaccharide mixtures are not so common (Willenberg et al, 2006;Yongsheng et al, 2008), and the quality is quite often not outstanding. At the best of our knowledge, quantitative analysis of the TEM image of alginate gels was previously reported only by one group Rayment et al, 2009).…”

Novel Biomaterials with Parallel Aligned Pore Channels by Directed Ionotropic Gelation of Alginate: Mimicking the Anisotropic Structure of Bone Tissue

“…30% due to the pore channel diameter but the walls consist of an alginate network with a high nano-porosity. The pore density was found to be 530/mm 2 and the mean pore diameter around 30 µm for Cu 2+ as cation (Willenberg et al, 2006;Prang et al, 2006). Interestingly, using a different type of alginate gelled with Cu 2+ , we found a pore density of 124/mm 2 with an mean pore diameter of only 20 µm.…”

“…The pore distribution and run was characterized by µCT in ceramic (Goebbels et al, 2002) or composite (Despang et al, 2005b) state. Since 2005/6, the anisotropic structures have been subject of research in the area of tissue engineering with human cells for hard tissue (Despang et al, 2005a, Dittrich et al, 2006 and vascularisation (Yamamoto et al, 2010), in in vitro and in vivo studies in rats for nerve regeneration and with murine embryonic stem cells opening opportunities for the formation of many types of tissue (Willenberg et al, 2006). A more detailed and chronological list of scientific contributions to the field with short summaries of their content follows (Table 1).…”