Intracellularly monitoring/imaging the release of doxorubicin from pH-responsive nanoparticles using Förster resonance energy transfer.
Stimuli-responsive nanoparticles (NPs) have been receiving much attention as a drug-delivery vehicle for therapeutic applications; once internalized into cells, the intracellular fate of NPs and their drug release behavior in response to local stimuli must be understood for efficient delivery of therapeutics. In this study, we prepared pH-responsive doxorubicin (DOX)-loaded NPs, made of N-palmitoyl chitosan bearing a Cy5 moiety (Cy5-NPCS), as an anticancer delivery device. The results of our molecular dynamic simulations showed that the ability of Cy5-NPCS to self-associate offered the close proximity between the donor (DOX) and the acceptor (Cy5) required for Förster resonance energy transfer (FRET), while the pH-driven structure transition prescribed the on-to-off switch of the energy transfer. The caveolae-mediated pathway played a major role in the internalization of NPCS NPs. Using the concept of FRET, we found that the DOX fluorescence in the cytosol was first seen when NPCS NPs were present in the slightly acidic early endosomes. Following NPCS NPs trafficking into a more acidic organelle (late endosomes/lysosomes), a more evident release of DOX into the cytosol was observed; the released DOX was then gradually accumulated in the cell nuclei, leading to a significant cytotoxicity. Understanding the fate of NPs with respect to their intracellular localization and drug release behavior is crucial for the rational design of drug carriers.
Department of Chemical Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan, ROC.
Ko-Jie
KJ
Chen
Ya-Ling
YL
Chiu
Yu-Ming
YM
Chen
Yi-Cheng
YC
Ho
Hsing-Wen
HW
Sung
D001692:Biological Transport / Q000187:drug effects; D002232:Carbocyanines / Q000737:chemistry; D016923:Cell Death / Q000187:drug effects; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D048271:Chitosan / Q000031:analogs & derivatives / Q000737:chemistry; D004317:Doxorubicin / Q000737:chemistry / Q000494:pharmacology*; D004705:Endocytosis / Q000187:drug effects; D031541:Fluorescence Resonance Energy Transfer / Q000379:methods*; D006801:Humans; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D042541:Intracellular Space / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D056004:Molecular Dynamics Simulation; D057054:Molecular Imaging / Q000379:methods*; D053758:Nanoparticles / Q000737:chemistry*; D010316:Particle Size; D055672:Static Electricity
D002232:Carbocyanines; C510699:N-palmitoyl chitosan; C085321:cyanine dye 5; D004317:Doxorubicin; D048271:Chitosan