Passive targeting also entails the use of innate feature of the NP such as charge to target the tumor. Tumor cells bear relatively high negative surface charge than normal cells, thereby enabling favored binding by cationic NP systems.15 Targeting of cationic NP system is achieved by electrostatic binding to negatively charged phospholipid headgroups preferentially expressed on tumor endothelial cells.16,17 The cytotoxicity potential of polymeric NPs largely depends on cellular internalization and subcellular localization of the NPs, which is governed by the nature of polymeric surface charge (anionic, cationic, or neutral).18 Cationic NPs have been found to efficiently deliver small interfering RNA (siRNA) to silence target gene in cancer cells and also sensitize the cancer cells to the effect of paclitaxel (PTX) for improved anticancer activity.19,20