The effect of α-cyclodextrin on poly(pseudo)rotaxane nanoparticles self-assembled by protoporphyrin modified poly(ethylene glycol) for anticancer drug delivery

Poly(pseudo)rotaxane (PPR) nanoparticles was facilely prepared using poly(ethylene glycol) (PEG) modified with protoporphyrin (PpIX) and α-cyclodextrin (α-CD) via host-guest interaction, the effect of α-CD number on the nanoparticle properties was investigated. The PEG with protoporphyrin (PEG-PpIX) end capping was synthesized via coupling reaction and the poly(pseudo)rotaxane nanoparticles with different amount of α-CD were fabricated by host-guest interaction between mPEG-PpIX and α-CDs. The final product was characterized by nuclear magnetic spectrum (1H NMR), X-ray diffraction (XRD), atomic force microscope (AFM) and dynamic light scattering (DLS). The results showed that the poly(pseudo)rotaxane nanoparticles with uniform spherical shape was successfully prepared and doxorubicin (DOX) could be efficiently encapsulated in the nanoparticles. The amount of α-CDs in poly(pseudo)rotaxane nanoparticles was proportional to micellar size and drug release rate. The nanoparticles with higher α-CD number showed better anticancer efficacy in half maximal inhibitory concentration (IC50) test. The cell internalization efficiency of DOX-loaded poly(pseudo)rotaxane nanoparticles could be further improved by lowering the α-CD number to receive smaller nanoparticle size.