Rhamnolipid nanoparticles for in vivo drug delivery and photodynamic therapy.

Herein, we report the development of self-assembled nanoparticles using rhamnolipid, a biosurfactant. Rhamnolipid is produced by Pseudomonas aeruginosa, and has an amphiphilic structure that is suitable for the formation of a nanoparticle shell. These rhamnolipid nanoparticles were loaded with pheophorbide a (Pba), a hydrophobic photosensitizer. The resulting nanoparticles had about 136.1-nm-diameter spherical shapes and had excellent water solubility without aggregation for one month. These nanoparticles showed fast uptake into SCC7 tumor cells and induced photodynamic damage upon laser irradiation. After intravenous injection to SCC7 tumor-bearing mice, their long blood circulation time and high accumulation in tumor tissue were observed in real-time fluorescence imaging. Upon laser irradiation, these rhamnolipid nanoparticles showed complete tumor suppression by photodynamic therapy in vivo. These promising results demonstrate the potential of rhamnolipid nanoparticles for drug delivery, and suggest that further attention to rhamnolipid research would be fruitful.