PHA granule binding protein PhaP is able to bind to hydrophobic polymers
(Wang et al. 2008b). A receptor-mediated drug-specific delivery system was developed
in this study based on PhaP (Fig. 5). The system consists of PHA nanoparticles,
PhaP, and ligands fused to PhaP. The PHA nanoparticles were used to
package mostly hydrophobic drugs, PhaP fused with ligands produced by overexpression
of their corresponding genes in Pichia pastoris or Escherichia coli was able
to attach to hydrophobic PHA nanoparticle. At the end, the ligands were able to pull
the PhaP–PHA nanoparticles to the targeted cells with receptors recognized by the
ligands. It was found in this study that the receptor-mediated drug-specific delivery
Fig. 5