Nevertheless, it is becoming commonly accepted that the development of fullybiodegradable materials is required to avoid the concerns of accumulation of ixitainedmaterials, in particular for long-term use or high dose therapies such as chemotherapy,rherefore, this major hurdle in nanomcdicinc drives us to design a new platform able to beeliminated or excreted from the organism. On one hand, silica based organic-inorganichybrids are well-demonstrated as inert, and therefore, biocompatible materials. Such materialstypically do not show an inherent biodegradability, an essential requirement for therapeuticapplications. Polyphosphazcncs, on the other hand, are unique polymers made of aphosphorous-nitrogen backbone, well known for their degradabiiity in an appropriate timeframe into non-toxic degradation products and intermediates. Thus, we combined both