Dissipative Particle Dynamics Simulation On The Self-assembled Behavior Of Polymers/Gold Nanoparticles Composite Micelles

The functional nanocomposites formed by self-assembly of polymers and gold nanoparticles are widely used in the fields such as medicine examination,tracking probe and biology.Dissipative particle dynamics(DPD)simulation was employed to investigate the relationship between structure and performance of these functional nanocomposites in siRNA/polymer/AuNPs system and PHFBM-PDEAM-PEO/gold nanoparticles system,which may provide valuable guidance in later design and optimization of functional self-assembled nanocomposites.The main works are as follows:DPD simulation was used to reveal the loading/release of small interfering RNA(siRNA)in pH-sensitive polymers/gold nanoparticles(AuNPs)polyplex.The conformation dynamics of these polyplex at various Au/siRNA mass ratios,the original AuNPs sizes,polymer types,and pH values were simulated and compared to experimental results.At neutral conditions(pH=7.4),spherical micelles with a multilayer structure are formed in siRNA/polyethyleneimine/cis-aconitic anhydride functionalized poly(allylamine)/polyethyleneimine/11-mercaptoundecanoic acid-gold nanoparticle(siRNA/PEI/PAH-Cit/PEI/MUA-AuNPs)polyplex.Large polyplex are obtained with high Au/siRNA mass ratio and/or small original AuNPs size.The release dynamics of siRNA from AuNPs-polyplex systems were also simulated in the intracellular environment(pH=5.0).A swelling-demicellization-releasing mechanism is followed while the release of siRNA is found much faster for polyplex involving charge-reversal PAH-Cit.The cytotoxicity of siRNA/PEI/PAH-Cit/PEI/MUA-AuNPs polyplex can be significantly reduced when compared to their counterparts without AuNPs core.DPD simulation was also used to design PHFBM-PDEAM-PEO triblock copolymer which may be used to prepare monodisperse composite nanoparticles.And it was performed to investigate the self-assembly dynamics process of PHFBM-PDEAM-PEO triblock copolymer and gold nanoparticles in aqueous solution.The simulations show that triblock copolymer concentration,the composition of PHFBM-PDEAM-PEO triblock copolymer,the volume fraction of PHFBM-PDEAM-PEO and/or gold nanoparticles had significant effects on the structure and size of the self-assembly micelles.The simulation results show that using shorter hydrophobic or middle chains and longer hydrophilic chains is more favorable to formation of monodisperse composite nanoparticles with three-layer core-shell structures.