ABSTRACT
Liposome has been demonstrated as one of the most clinically advanced drugdelivery systems (Lian and Ho 2001; Allen and Cullis 2013). Its applications include chemotherapy, vaccine, gene delivery, infectious diseases, and so on (Balazs and Godbey 2011; Soenen et al. 2011). Liposome is easy to prepare and is able to encapsulate both hydrophilic and hydrophobic drugs (Al-Jamal and Kostarelos 2011). However, liposome without surface modification, that is, naked liposome, is prone to be damaged or cleared by the components in blood stream, which accounts for its short circulation time, high drug leakage, and reduced pharmaceutical efficacy. Another disadvantage of naked liposome is the deficiency of targeting specific cells when administrated in vivo, causing strong side effects. Therefore, the surface of liposome is usually modified by agent of certain functions to solve one or more of the problems. For example, the circulation time of liposome in the blood stream is significantly prolonged with the attachment of polyethylene glycol (PEG) on the surface (Klibano et al. 1990; Blume and Cevc 1993; Blume et al. 1993). Besides PEG, polysaccharides, peptides, and other biocompatible molecules, have also been tested
Beijing National Laboratory for Molecular Sciences and the Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing, China, 100871.
