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The decrease of PAMAM dendrimer-induced cytotoxicity by PEGylation via attenuation of oxidative stress
Wei Wang1, Wei Xiong, Jiangling Wan
1College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China.
Nanotechnology
|May 7, 2009
Summary
Poly(amidoamine) (PAMAM) dendrimers, used in medicine, can be made less toxic. PEGylation of PAMAM dendrimers significantly reduced their cytotoxicity by improving biocompatibility.
Area of Science:
- Biomaterials Science
- Nanomedicine
- Polymer Chemistry
Background:
- Poly(amidoamine) (PAMAM) dendrimers are utilized in various medical applications due to their unique structure.
- Amino-terminated PAMAM dendrimers exhibit inherent cytotoxicity, limiting their therapeutic potential.
- Improving the biocompatibility of PAMAM dendrimers is crucial for safe clinical translation.
Purpose of the Study:
- To enhance the biocompatibility of Generation-5 PAMAM dendrimers.
- To investigate the impact of poly(ethylene glycol) (PEG) conjugation on PAMAM dendrimer cytotoxicity.
- To elucidate the molecular mechanisms underlying PEGylation-mediated reduction in cytotoxicity.
Main Methods:
- Generation-5 PAMAM dendrimers were conjugated with poly(ethylene glycol) (PEG) of varying molecular weights and chain densities.
- Cytotoxicity was assessed by determining IC(50) values.
- Intracellular responses including reactive oxygen species (ROS) production, mitochondrial membrane potential (MMP) changes, and apoptosis were analyzed.
- Endocytic properties were evaluated to understand cellular uptake mechanisms.
Main Results:
- PEGylated PAMAM dendrimers demonstrated significantly higher IC(50) values (12-105 fold increase) compared to unmodified PAMAM dendrimers.
- PEGylation effectively attenuated ROS production and prevented the collapse of MMP, thereby reducing PAMAM-induced apoptosis.
- Dendrimers with higher molecular weight and greater PEGylation density exhibited markedly lower cytotoxicity.
- Endocytic properties remained largely unchanged for dendrimers with lower PEGylation.
Conclusions:
- Conjugation with poly(ethylene glycol) is a viable strategy to significantly reduce the cytotoxicity of PAMAM dendrimers.
- PEGylation mitigates PAMAM-induced cellular damage by modulating intracellular ROS levels and mitochondrial function.
- The degree of PEGylation, specifically molecular weight and chain density, influences the extent of cytotoxicity reduction, offering a tunable approach for developing safer nanomedicines.
