Adherent cell manufacturing is hindered by the necessity to use solid substrates or hydrogels for their culture and expansion. Such materials and platforms are relatively difficult to scale up and parallelise. In contrast, liquid-liquid technologies and microdroplet platforms have been applied very successfully in the field of Chemical Engineering for the scale up of synthesis and purification of fine chemicals, therapeutics, polymers and nanomaterials. Yet, their use in the field of biotechnologies is largely confined to the high throughput screening of single planktonic cells. We recently reported that the culture of adherent stem cells at the surface of liquids [1, 2] was mediated by the self-assembly of protein nanosheets forming mechanically strong interfaces [3, 4, 5]. We now examine the chemical design of protein nanosheets systematically and identify groups of pro-surfactant molecules effectively supporting stem cell expansion at liquid interfaces. We observe that cell proliferation correlcates with the viscoelastic behaviour of protein nanosheets. In particular, the multi-scale viscoelasticity of liquid-liquid interfaces, rather than corresponding shear moduli, is an important physical determinant of stem cell proliferation. Based on neutron reflectometry, TEM and polarised optical microscopy, we report that this behaviour is controlled by the nanoscale organisation of prosurfactant-mediated rigid domains. Overall, our results pave the way to the use of microdroplet technologies and liquid-liquid interfaces in the field of tissue engineering and for stem cell technologies.

Engineering liquid interfaces with viscoelastic 2D protein networks - microdroplet design for stem cell technologies

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.