For example, Panyam and colleagues developed a biotin-functionalized PLGA/PLA-PEG nanoparticle for the co-delivery of paclitaxel and tariquidar, a potent P-gp inhibitor, to drug-resistant tumor cells and observed superior anti-tumor efficacy both in vitro and in vivo when compared with non-targeted nanoparticles.305 Similar results were obtained using biotin-functionalized PLGA-PEI nanoparticles loaded with paclitaxel and P-gp siRNA.306. Here, PGP is linked to neoplasm.