Targeted delivery of proteins by nanosized carriers

Proteic drug administration poses some additional issues as compared with conventional drugs because of protein high molecular weight and short half-life in plasma. It is well known that protein delivery can be significantly improved by using targeted nanocarriers. Among the diverse investigated systems, this overview focuses on liposomes and nanoparticles. Indeed, because of their subcellular size, nanocarriers can cross the fenestration of the vascular epithelium and penetrate tissues. Moreover, nanosystems can be confined at the location of choice by conjugation to molecules that strongly bind the target cells. In spite of the significant progress made in the design and engineering of liposomes and nanoparticles tailored to the targeted delivery of proteins, these nanocarriers seldom succeed in delivering proteins directly inside the cell cytosol. Accordingly, some attention is also paid to virosomes and fusion proteins. These systems have a few advantages over conventional nanocarriers, particularly the ability to cross the cell membrane. They also share the main drawback of being highly immunogenic. (c) 2007 Wiley Periodicals, Inc.