Selection of a suitable photosynthetically active microalgae strain for the co-cultivation with mammalian cells

Abstract

Preventing hypoxic zones in 3D bioprinted mammalian cell-laden constructs using an internal oxygen supply could enable a more successful cultivation both in vitro and in vivo. In this study, the suitability of green microalgae as photosynthetic oxygen generators within bioprinted constructs was evaluated by defining and investigating important parameters for a successful co-culture. First, we assessed the impact of light–necessary for photosynthesis–on two non-light adapted mammalian cell types and defined red-light illumination and a temperature of 37°C as essential factors in a co-culture. The four thermotolerant microalgae strains Chlorella sorokiniana, Coelastrella oocystiformis, Coelastrella striolata, and Scenedesmus sp. were cultured both in suspension culture and 3D bioprinted constructs to assess viability and photosynthetic activity under these defined co-culture conditions. Scenedesmus sp. proved to be performing best under red light and 37°C as well as immobilized in a bioprinted hydrogel based on alginate. Moreover, the presence of the antibiotic ampicillin and the organic carbon-source glucose, both required for mammalian cell cultures, had no impact on bioprinted Scenedesmus sp. cultures regarding growth, viability, and photosynthetic activity. This study is the first to investigate the influence of mammalian cell requirements on the metabolism and photosynthetic ability of different microalgal strains. In a co-culture, the strain Scenedesmus sp. could provide a stable oxygenation that ensures the functionality of the mammalian cells.

3D bioprinting of mineralizing cyanobacteria as novel approach for the fabrication of living building materials

“…3D bioprinting was investigated as a manufacturing method to produce LBM, since recent studies analyzing 3D bioprinting of bacteria, such as Escherichia coli (Lehner et al, 2017), Bacillus subtilis (Huang et al, 2019), or Acetobacter xylinum (Schaffner et al, 2017), demonstrated good cell viability and functionality over days up to several weeks. A blend of alginate and methylcellulose (algMC) was chosen as the hydrogel matrix of the LBM because it is a well-established bioink for extrusionbased bioprinting that exhibits high biocompatibility with various mammalian and non-mammalian cell types (Lode et al, 2015;Ahlfeld et al, 2017;Schütz et al, 2017;Dani et al, 2022).…”

“…3D bioprinting was investigated as a manufacturing method to produce LBM, since recent studies analyzing 3D bioprinting of bacteria, such as Escherichia coli ( Lehner et al, 2017 ), Bacillus subtilis ( Huang et al, 2019 ), or Acetobacter xylinum ( Schaffner et al, 2017 ) , demonstrated good cell viability and functionality over days up to several weeks. A blend of alginate and methylcellulose (algMC) was chosen as the hydrogel matrix of the LBM because it is a well-established bioink for extrusion-based bioprinting that exhibits high biocompatibility with various mammalian and non-mammalian cell types ( Lode et al, 2015 ; Ahlfeld et al, 2017 ; Schütz et al, 2017 ; Dani et al, 2022 ). Alignate as a natural polymer has been used as an additive to mortar in several studies, which resulted in an increased compressive and tensile strength ( Susilorini et al, 2014 ; Mohesson and Abbas, 2020 ) and enhances the building materials flame-, fire-, and heat-resistance significantly ( DeBrouse, 2012 ).…”

Bioinks for Space Missions: The Influence of Long‐Term Storage of Alginate‐Methylcellulose‐Based Bioinks on Printability as well as Cell Viability and Function

“…The blends consisting of 3 wt% alginate and 9 wt% methylcellulose (Alg-MC) were prepared and laden with the different cell types at room temperature; cell densities were chosen based on our previous studies. [11,12,15,18,20,22,26] One aliquot of each bioink was filled into a cartridge for immediate use for extrusionbased bioprinting without storage (W0), four aliquots were filled into separate cartridges and the four cartridges were transferred to 4°C for storage. After 1-4 weeks of storage (W1-W4), the cartridges were brought to room temperature and used for bioprinting.…”

“…The high viability (≈ 90% observed for W0) and the growth of embedded C. vulgaris after bioprinting in Alg-MC is consistent with the findings for other bioprinted microalgae such as C. reinhardtii, Chlorella sorokiniana and Scenedesmus sp. [17,18,40] The storage at 4°C can be expected to have a stronger impact on the living part of bioinks, the cells. For the microalgae, only a marginal decrease of viability throughout the 7 days of cultivation, due to cold storage of the bioink was detected.…”

“…[11] During alginate crosslinking and the subsequent cultivation, the methylcellulose is partially released, forming a crosslinked construct of mainly alginate.. [11,12] This versatile ink has been successfully applied for bioprinting of various mammalian cell types such as pancreatic islets of Langerhans and chondrocytes, but also for bioprinting of microalgae. [13][14][15][16][17][18][19] Based on the promising results in these ground-based studies, Alg-MC was the first bioink to be selected by the company OHB for use in space. As part of the ISS mission Cosmic Kiss of the German ESA astronaut Matthias Maurer, it was used as one of two for the mission selected bioinks to generate constructs with the aid of a hand-held printer, which in combination with dermal fibroblasts should later provide rapid assistance in the wound closure of large-area skin injuries.…”