Interactions between PAMAM dendrimers and DOPC lipid multilayers: Membrane thinning and structural disorder

Area of Science:

• Materials Science
• Nanotechnology
• Biophysics

Background:

• Hybrid nanoparticle-lipid multilayers are crucial for bioanalytical applications and understanding nanotoxicity.
• Poly(amidoamine) (PAMAM) dendrimers offer tunable physicochemical properties for potential biomedical uses.
• Investigating nanoparticle-membrane interactions is key to their function and safety.

Purpose of the Study:

• To investigate the structural impact of PAMAM dendrimers on 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) multilayers.
• To determine how dendrimer size, surface termination (hydrophilic vs. hydrophobic), and addition method influence multilayer structure.

Main Methods:

• DOPC multilayers were formed using the liposome-rupture method with varying dendrimer concentrations and addition stages.
• Synchrotron X-ray reflectivity (XRR) was employed to analyze multilayer structure.
• Key structural parameters evaluated included bilayer d-spacing, coherence length (L_s), and paracrystalline disorder (g).

Main Results:

• Dendrimer incorporation resulted in lipid bilayer thinning and increased structural disorder.
• Larger hydrophobic dendrimers induced more significant structural disruption than smaller ones.
• The smallest, positively charged dendrimers at high concentrations caused the most pronounced thinning; addition method also influenced structure due to aggregation.

Conclusions:

• Dendrimer physicochemical properties and addition methods significantly and complexly affect hybrid multilayer structure.
• These findings are vital for understanding nanotoxicity mechanisms.
• Insights support the development of advanced nanocomposite multilayer materials for biomedical applications.