Fully animal-free manufacture of optimised growth factors: underpinning sustainable and scalable organoid culture for precision medicine, drug discovery and regenerative medicine applications

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Organoids are 3-dimensional (3D) clusters of stem cells that come together and emulate the microenvironment within individual organs, whether that be liver, kidney, heart, gut or other specific organs. Essentially, they can be viewed as miniature, simplified organs. They typically range in size from a few micrometers to five millimeters and there are potentially as many different organoids as there are different tissues and organs in the body. Organoids can also be grown that mimic diseased such as cancer and brain disorders. Such a diverse range of organoids can be formed by controlling the differentiation of the specific stem cell used, which can be influenced by the cells receiving instructive signals from proteins called growth factors, the 3D extracellular matrix (ECM) and its components, and chemical moieties in the medium the organoids grow in.Organoids hold extraordinary promise: they are a truly disruptive technology capable of completely transforming our understanding of basic biology and revolutionising the drug discovery process, and its reliance on animal models.That said, methods used for growing organoids in the laboratory need to be improved and standardised to allow wider adoption, particularly in drug discovery, and to make organoid culture easier and more reproducible. The two elements that need particular focus are the bioactive protein growth factors and the 3D gel matrix in which organoids grow. The matrix, a complex mixture of structural proteins and growth factors, is currently extracted from mouse tumours so there is a pressing need to make synthetic alternatives for reproducibility and to reduce use of animal-products.In our previous UKRI-funded project we developed optimised, highly defined forms of growth factors for organoid culture. Large multinational companies are now interested in bulk purchase of these and we need to undertake further R&D to scale manufacture, remove the use of beta-lactam antibiotics (which are not compatible with pre-clinical applications of organoids) and introduce a quality system ISO13485.In addition, there is one growth factor, called Wnt3a, which is crucial for the growth of many types of organoids and is not easily sourced. The few commercially available have variable bioactivity, are exceptionally expensive (<£17,000 /milligram) and are not made in a full animal-product-free process.We made a promising start on the R&D needed to solve this problem in the last project and wish to continue this work, using protein engineering technologies to make a highly bioactive, totally animal-free and cost-effective Wnt protein.