 Natural hydrogels such as Matrigel, collagen and fibrin have been used as entrapement matrices, wherein the cells to be injected are embedded.However the associated high pressure of injection is associated with a high mortality rate for the cells thereby negatively impacting the benefit ratio of this approach.Furthermore, from a technical point of view, due to the polydispersite of these natural hydrogels, purification is a requisite but very difficult step.