Polysilsesquioxane nanoparticles (PSilQ NPs) are a hybrid material made of organic and inorganic components.  PSilQ NPs are an attractive platform for drug delivery applications because they have the ability to release a high concentration of active molecules in a target-specific fashion after being functionalized with targeting agents.  In this project, we synthesized and characterized a porphyrin-based building block for the fabrication of PSilQ NPs. The PSilQ precursor includes protoporphyrin-IX (PpIX), a photoactive molecule; and disulfide bond-containing molecular chains, as redox responsive linkers.  Moreover, this building molecule also contains free carboxylic acids chemically available for further functionalization, once the PSilQ NPs have been synthesized. In this project we had modified the surface of PpIX-PSilQ NPs with targeting agents (e.g. folic acid) and polyethylene glycol (PEG).  The synthesis of the PpIX-based building block was carried out through a multi-step synthetic approach and characterized using <sup>1</sup>H-NMR, UV-Vis spectroscopy, MALDI-MS, and IR spectra.  The PSilQ NPs were fabricated by using the reverse microemulsion method and characterized by dynamic light scattering (DLS)/zeta potential, UV-Vis, scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). SEM micrographs showed particles to be around 45 nm in diameter, containing 46% of PpIX based on TGA.  After functionalization with FA-PEG, the surface potential changes from -35 mV to a neutral charge.  The targeting and phototoxic properties of FA-PEG-PpIX-PSilQ NPs were successfully tested in human cervical cancer (HeLa) cells.  We envision that this novel PSilQ platform may enhance the phototherapeutic effect of photodynamic therapy for cancer treatment.

Folic-acid functionalized polysilsesquioxane nanoparticles for targeted delivery of protoporphyrin-IX

251st National Meeting (2016)

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