Periodic Reporting for period 3 - ECM_INK (Cells-self Extracellular Matrices-based Bioinks to create accurate 3D diseased skin tissue models)
Reporting period: 2020-05-01 to 2021-10-31
Lately, bioprinting technology has captured attention as it allows a better recreation of the human tissue characteristics and the development of more reliable 3D in vitro models. Bioinks are a key element of bioprinting as they are the building pillars for a functional cellular structure in these novel models. Although several hydrogel approaches have been used for the development of more functional bioinks, considerable work is still needed to achieve formulations allowing engineered tissue to function as desired. For this purpose, ECM_INK aims to develop new bioinks that fully mimic the native environment to be recreated hypothesizing that this is mandatory to be able to build accurate skin models fully representative of the pathophysiology of diseases such as pemphigus vulgaris, dystrophic epidermolysis bullosa and squamous cell carcinoma.
Additionally, different ECM extraction protocols have been trialled in order to obtain optimal protein content without losing critical native features. This was achieved by looking at the ECM contents from different perspectives and considering its subsequent use in the bioinks composition. Therefore, different ECM contents were obtained and combined with a biomaterial; depending on the chemistry of the material, the type of the extract and the amount of extract and material, different bioinks capable of being printed and forming stable hydrogel-like structures, various bioinks were obtained. So far, these were shown to influence cell behaviour and the specific effect over cell phenotype is currently being assessed. Moreover, based on the specificities of the bioinks a customised print head and an extrusion-based bioprinter were developed. This permitted higher printing versatility and precision allowing, for example, the creation of gradients of cell concentrations and materials determinant for the creation of a diseased environment within a surrounding normal tissue.
Considering the ultimate goal of the project of creating skin diseases models that can be used as in vitro platform for varied tests, a micro-bioreactor that allows for in vitro preparation, maintenance and conditioning of human skin tissues in a setting that can provide each layer of tissue with separate nourishing fluids according to its requirements was developed. The bioreactor was built with a modular design that permits its expansion for culturing more complex multilayer tissue or multi-tissue structures.
Ultimately the models to be developed will provide unprecedented human-origin 3D in vitro systems in which a wide range of mechanistic questions regarding pemphigus vulgaris, dystrophic epidermolysis bullosa and squamous cell carcinoma can be addressed. Thus more accurate and translatable therapeutic targets can be revealed or therapy-related knowledge generated than those obtained with animal experimentation.