One of the currently challenges in nanomedicine is the control of the degradation of drug carrier particles inside the human body to small molecules which can be excreted. The aim of this master thesis was the design and development of a material capable of degrading into low molecular weight, excretable and harmless products. Polyphosphazenes are unique polymers made of a phosphorous-nitrogen backbone, well known for their degradability in an appropriate time frame into non-toxic degradation products and intermediates. Additionally, periodic mesoporous organosilicas (PMOs) are a type of mesoporous silica materials, which have pores. The porosity makes them a promising supports for drug delivery purposes, due to the possibility to upload the pores with the drug molecules.
A problem of the well-known mesoporous silica nanoparticles is that they are not degradable. Thus, in this work it was attempted to combine polyphosphazenes with periodic mesoporous silica materials to create novel degradable silica nanoparticles. In the first part of this thesis, various derivative polyphosphazene polymers with different chain lengths were synthesized and characterized. These polymers were used as a precursor in the preparation of silica nanoparticles, by using the sol-gel process. This novel combination of polyphosphazenes and silica nanoparticles was successful, so mesoporous silica nanoparticles could be prepared using polyphosphazenes. The prepared nanoparticles were fully characterized with different techniques, such as dynamic light scattering (DLS), N2 adsorption-desorption isotherms (BET and BJH method), fourier transform-infrared spectroscopy (FT-IR) and transmission electron microscopy (TEM). Through analysis of the prepared nanoparticles with these characterization techniques it could be verified, that nanoparticles were prepared and images obtained with the transmission electron microscope showed, that the particles had pores. The second part of this work comprises degradability studies of the prepared organosilica nanoparticles. These studies were carried out at different times and conditions at pathologic acidic conditions, pH 2, and at physiological pH 7, as a control. Possible changes in the chemical structure of these silica-based materials, and thus, degradation of the nanoparticles, were successfully verified by transmission electron microscopy, confirming the promising proof-of-concept of these novel degradable PMO materials based on polyphosphazenes.