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Cultivated meat is an emerging field, aiming to establish the production of animal tissue for human consumption in an in vitro environment, eliminating the need to raise and slaughter animals for their meat. To realise this, the expansion of primary cells in a bioreactor is needed to achieve the high cell numbers required. The aim of this study was to develop a scalable, microcarrier based, intensified bioprocess for the expansion of bovine adipose-derived stem cells as precursors of fat and muscle tissue. The intensified bioprocess development was carried out initially in spinner flasks of different sizes and then translated to fully controlled litre scale benchtop bioreactors. Bioprocess intensification was achieved by utilising the previously demonstrated bead-to-bead transfer phenomenon and through the combined addition of microcarrier and medium to double the existing surface area and working volume in the bioreactor. Choosing the optimal time point for the additions was critical in enhancing the cell expansion. A significant fold increase of 114.19 ± 1.07 was obtained at the litre scale in the intensified bioprocess compared to the baseline (**p < .005). The quality of the cells was evaluated pre- and post-expansion and the cells were found to maintain their phenotype and differentiation capacity.

Cultured meat is an emergent technology with the potential for significant environmental and animal welfare benefits. Accurate mimicry of traditional meat requires fat tissue; a key contributor to both the flavour and texture of meat. Here, we show that fibro-adipogenic progenitor cells (FAPs) are present in bovine muscle, and are transcriptionally and immunophenotypically distinct from satellite cells. These two cell types can be purified from a single muscle sample using a simple fluorescence-activated cell sorting (FACS) strategy. FAPs demonstrate high levels of adipogenic potential, as measured by gene expression changes and lipid accumulation, and can be proliferated for a large number of population doublings, demonstrating their suitability for a scalable cultured meat production process. Crucially, FAPs reach a mature level of adipogenic differentiation in three-dimensional, edible hydrogels. The resultant tissue accurately mimics traditional beef fat in terms of lipid profile and taste, and FAPs thus represent a promising candidate cell type for the production of cultured fat.

Cultured meat is a bearer of hope for sustainable meat production, aiming at ensuring global food security while preserving environmental resources. Being a nascent industry, there are still many hurdles to overcome, some of which are cost reduction and ensuring a sustainable supply chain. This review focuses on the current state of the industry, identifies medium -related costs as one of the main cost drivers for scalable cultured meat production and discusses the latest findings on potential cost-effective nutrient replacements for cell propagation and differentiation, based on hydrolysates. Opportunities for medium recyclability with a focus on algae are also explored.

Biotechnology letters 41(11), 1245-1253 (2019). doi:10.1007/s10529-019-02732-z, Published by Springer Science + Business Media B.V, Dordrecht [u.a.]

Background: Within the healthcare industry, including the care of chronic wounds, the challenge of antimicrobial resistance continues to grow. As such, there is a need to develop new treatments that can reduce the bioburden in wounds. Objective: The present study is focused on the development of polyaniline (PANI) / chitosan (CH) nanofibrous electrospun membranes and evaluates their antibacterial properties. Methods: To this end, experimental design was used to determine the electrospinning windows of both pure chitosan and PANI/CH blends of different ratios (1:3, 3:5, 1:1). The effect of key environmental and process parameters (relative humidity and applied voltage) was determined, as well as the effect of the PANI/CH ratio in the blend and the molecular interactions between PANI and chitosan that led to jet stability. Results: The nanofibrous mats were evaluated regarding their morphology and antibacterial effect against model gram positive and gram negative bacterial strains, namely B. subtilis and E. coli. High PANI content mats show increased bactericidal activity against both bacterial strains. Conclusion: The blend fibre membranes combine the materials’ respective properties, namely electrical conductivity, biocompatibility and antibacterial activity. This study suggests that electrospun PANI/CH membranes are promising candidates for healthcare applications, such as wound dressings.

Producing meat without the drawbacks of conventional animal agriculture would greatly contribute to future food and nutrition security. This Review Article covers biological, technological, regulatory and consumer acceptance challenges in this developing field of biotechnology. Cellular agriculture is an emerging branch of biotechnology that aims to address issues associated with the environmental impact, animal welfare and sustainability challenges of conventional animal farming for meat production. Cultured meat can be produced by applying current cell culture practices and biomanufacturing methods and utilizing mammalian cell lines and cell and gene therapy products to generate tissue or nutritional proteins for human consumption. However, significant improvements and modifications are needed for the process to be cost efficient and robust enough to be brought to production at scale for food supply. Here, we review the scientific and social challenges in transforming cultured meat into a viable commercial option, covering aspects from cell selection and medium optimization to biomaterials, tissue engineering, regulation and consumer acceptance.

The demand for meat is expected to exceed production capacity by livestock in the coming decennia. Therefore, cultured beef might be a viable alternative to traditional livestock-derived beef. One of the problems however is the sustainability of cultured beef through the use of fetal bovine serum. We aimed to identify a serum-free medium or a serum-replacement that is as effective as the current method used for culturing bovine myoblasts. Cells were harvested from a female Blanc Bleu Belge cow and myoblasts were subsequently isolated. Cells were cultured in either Advanced DMEM containing 20% FBS and 10% HS or one of the chemically-defined, serum-free media for 6 days. MTS was used as a measure of cell proliferation at day 1, 4 or 6 and microscopic pictures were taken to assess cell morphology. FBM™, TesR™ and Essential 8™ are commercially available xeno-free media developed for human PSCs and fibroblasts, with the highest potential to sustain bovine myoblast proliferation. Of the supplements tested, XenoFree™ and a custom-prepared growth factor mix failed to stimulate cell proliferation. LipoGro™ stimulated cell proliferation in some cases but also changed the phenotype of myoblasts to an adipocyte-like phenotype. We conclude that serum-free media stimulate exponential cell expansion, albeit not to the extent of the current growth medium containing up to 30% serum. Further research is needed to investigate whether prolonged cell culture or an adaptation period could further increase cell proliferation.

As electroactive polymers have recently presented potential in applications in the tissue engineering and biomedical field, this study is aiming at the fabrication of composite nanofibrous membranes containing conducting polyaniline and at the evaluation of their biocompatibility. For that purpose, conducting polyaniline–chitosan (PANI/CS) defect free nanofibres of different ratios (1:3; 3:5 and 1:1) were produced with the electrospinning method. They were characterized as for their morphology, hydrophilicity and electrical conductivity. The membranes were then evaluated for their cellular biocompatibility in terms of cell attachment, morphology and cell proliferation. The effect of the PANI content on the membrane properties is discussed. Increase in PANI content resulted in membranes with higher hydrophobicity and higher electrical conductivity. It was found that none of the membranes showed any toxic effects on osteoblasts and fibroblasts, and that they all supported cell attachment and growth, even to a greater extent than tissue culture plastic. The membrane with the PANI/CS ratio 1:3 supports better cell attachment and proliferation for both cell lines due to a synergistic effect of hydrophilicity retention due to the high chitosan content and the conductivity that PANI introduced to the membrane.

Polyaniline doped with CSA/PEO conductive nanofibers were produced by electrospinning. The electrospinning window was determined by using a three level, full factorial experimental design. The combined effects of the humidity, voltage and flow rate on the fiber morphology and diameter were examined demonstrating that the ambient humidity is the critical factor affecting the electrospinning process and determining the electrospinning window for a conductive polymer. Low humidity favors the formation of defect free fibers while high humidity either hinders fiber formation or causes the formation of defects on the fibers either due to jet discharge or due to water absorption and phase separation. High level of doping with CSA led to the formation of crystalline structures. Data fitting was used to explore the behavior of conductive polymers in electrospinning and very good agreement between experimental and theoretical predictions was obtained for only a limited range of experimental conditions, whereas deviation was observed for all other sets of conditions.