Biopolymers, such as polysaccharides and proteins show remarkable versatility as multifunctional materials. These biomolecular scaffolds are attractive as materials since they can be easily modified with a variety of bioorthogonal ligation reactions. Especially proteins are interesting for the formation of nanoparticles, since they are structurally well-defined biomaterials. In particular in areas of biodegradability, non-antigenicity, binding capacity and toxicity they can have advantages over synthetic polymers.<br/><br/>We designed a nanoparticle delivery system based on the assembly of surface modified proteins. The new concept is based on a lipophilic solubility switch of the protein material by high surface PEGylation. We evaluated the protein-polymer conjugation by using polyethylene glycol that is functionalized with different electrophile linker groups. We found that the introduced PEGs lead to no significant alteration of the secondary protein structure and in many cases the protein activity is still retained. Nanoparticles are prepared by an oil-in-water emulsion method without the need of additional crosslinking steps for stabilization. During the preparation hydrophobic drugs, e.g. doxorubicin (DOX) can be encapsulated in the particle matrix. We prepared empty and DOX-loaded nanoparticles with a size of around 100 nm in diameter. The particles are stable in physiological buffers and only release their payload into the cytosol after cellular uptake.<br/><br/>This novel method for the preparation of protein nanoparticles extends the range of biocompatible materials beyond current known synthetic polymers and potentially opens up new strategies for therapeutic applications.

Protein surface PEGylation for the emulsion-based formation of stable nanoparticles

253rd National Meeting (2017)

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