n the thesis entitled Biofunctionalization of alginate microcapsules: advances in cell-based drug delivery systems, three experimental studies based on modified alginate microcapsules with different densities of the RGD adhesion peptide have been carried out. The specific objectives of the work carried out are as follows: 1. Design alginate microcapsules made with different densities of RGD to evaluate the behaviour of immobilized cells in terms of viability, proliferation and secretion of therapeutic factor. 2. To evaluate the influence of different densities of RGD on the behaviour of different cell types in order to determine the optimal density of the adhesion ligand that provides the greatest cellular activity in each cell type. 3. To compare the effects of different densities of in vitro RGD with the results obtained in vivo.