Electrostatic theory of the assembly of PAMAM dendrimers and DNA

Abstract

The electrostatic interactions mediated by counterions between a cationic PAMAM dendrimer, modelized as a sphere of radius and cationic surface charge highly increasing with generation, and a DNA, modelized as an anionic elastic line, are analytically calculated in the framework of condensation theory. Under these interactions the DNA is wrapped around the sphere. For excess phosphates relative to dendrimer primary amines, the free energy of the DNA-dendrimer complex displays an absolute minimum when the complex is weakly negatively overcharged. This overcharging opposes gene delivery. For a highly positive dendrimer and a DNA fixed by experimental conditions to a number of phosphates less than the number of dendrimer primary amines, excess amine charges, the dendrimer may at the same time bind stably DNA and interact with negative cell membranes to activate cell transfection in fair agreement with molecular simulations and experiments.

Effect of the Anchoring Layer and Transport Type on the Adsorption Kinetics of Lambda Carrageenan

“…Contrary to bPEI, PAMAMDs possess a spherical shape in bulk. 50 , 51 PAMAMDs showed a fairly narrow size distribution with an average size of 10.2 nm practically independent of the pH, ionic strength of the buffer, and simple electrolyte type. 35 , 52 − 54 …”

“…49 Contrary to bPEI, PAMAMDs possess a spherical shape in bulk. 50,51 PAMAMDs showed a fairly narrow size distribution with an average size of 10.2 nm practically independent of the pH, ionic strength of the buffer, and simple electrolyte type. 35,52−54 The electrophoretic mobilities and zeta potentials of bPEI and PAMAMD were 3.66 μm cm/V s and 70 mV and 3.20 μm cm/V s and 60.8 mV, respectively (see Table 1).…”

Ultrasound-enhanced gene delivery to alfalfa cells by hPAMAM dendrimer nanoparticles

“…The cationic charge of the polymer is one of the most important factors for DNA condensation and gene delivery into eukaryotic cells. Cationic polymers such as PAMAM interact with the cells through electrostatic interactions between the cationic groups on PAMAM dendrimers and the anionic surface of the cells (Perico, 2016), which may be important for the cellular uptake of DNA complexed with PAMAM. Regarding the zeta-potential results, increasing the N/P ratio from 1 to 10 appeared to significantly increase the surface charge of hPAMAM-DNA complexes.…”