The object of the present invention is to provide particles of a polymeric material containing cells therein, wherein said particles have a strength that is substantially greater than the microcapsules known in the state of the art. Said strength is achieved by means of functionalizing the polymeric material forming the microcapsule with a peptide which can bind to the adhesion proteins of the cell membrane, such that the cells act as cross-linking agents of the matrix resulting in an improvement of the mechanical properties of the matrixes