HER2∼specific DARPin-Liposomes: Fabrication and characterization

Liposomes based on natural lipids and their analogues are regarded as promising agents for targeted delivery of antitumor drugs. We have created and characterized in vitro DARPin-liposomes specifically interacting with HER2 cancer marker expressed on the surface of many types of cancer cells. The surface of the liposomes was coated with polyethylene glycol to increase the circulation time of the liposomes in the bloodstream and to reduce nonspecific uptake by macrophages. As a targeting agent we used high- Affinity nonim- munoglobulin peptide DARPin9-29, specific to HER2 receptor. We anticipate that the created DARPin-li- posomes can be used for targeted delivery of anticancer drugs with different mechanisms of action. Besides, the incorporation of fluorescent label rhodamine covalently bound to phospholipids offers the possibility of applying the DARPin-liposomes for diagnostic purposes. We suggest that DARPin-liposomes represent a perspective system for further development and creation of multifunctional liposomal formulations.