Figure 2.

Characterization of NP–ZnPc(TAP)₄–Ptx.

Notes: (A) Particle size of NP–ZnPc(TAP)₄–Ptx detected using DLS: average 107 nm. (B) The ζ-potential was measured by DLS: average –28 mV. The coupling ratio was defined by the ratio of ZnPc(TAP)₄ concentration, Ptx concentration, and HSA concentration in the complex NP–ZnPc(TAP)₄–Ptx. (C) NP–ZnPc(TAP)₄–Ptx was stored in PBS with pH 7.4 for 14 days. Coupling ratios of ZnPc(TAP)₄:HSA and Ptx:HSA barely changed, which showed the stability of the complex. (D) The coupling ratio of Ptx:HSA was almost unchanged at any pH. The reduced coupling ratio of ZnPc(TAP)₄:HSA followed by pH decrease showed that ZnPc(TAP)₄ molecules had escaped from HSA NPs.

Abbreviations: ZnPc, zinc phthalocyanine; DLS, dynamic light scattering; Ptx, paclitaxel; HSA, human serum albumin.