Interaction of Polyamidoamine (pamam) Dendrimers with Glassy Carbon Supported Bilayer Lipid Membranes

Electrochemical techniques were used to monitor the formation of a 1,2-dioleoyl-sn-glycero-3-phosphocholine supported bilayer lipid membrane (sBLM) on a glassy carbon electrode and to investigate interactions of polyamidoamine (PAMAM) dendrimers with the sBLM. Dendrimers of generation 2 through generation 4 (G2-G4) did not cause significant damage to the sBLM, whereas G5G7 dendrimers created large defects in sBLM. In cyclic voltammetry studies, the peak current obtained after dendrimer addition was used to estimate the defect area. Impedance spectroscopy showed an increase in capacitance values after addition of G5-G7 dendrimers, consistent with a decrease in sBLM surface coverage. Nanoparticle mass, diameter, and surface charge density all increase significantly with generation number, suggesting that these variables may influence nanoparticles’ ability to rupture sBLM. The method presented here provides a convenient and sensitive way to detect interactions between nanoparticles and lipid bilayers, and may be useful in evaluating nanoparticles’ safety profile or suitability as drug or gene delivery vehicles.