Dendrimer−Polyelectrolyte Complexation:  A Model Guest−Host System

Abstract

Much experimental effort to realize possible uses of dendrimers has focused on the complexation of charged dendrimers to oppositely charged polyelectrolytes to form controlled delivery systems. Employing computer simulation and theory, we present a molecular-level picture of these guesthost aggregates and the conditions necessary for forming them. Specifically, we examine the equilibrium and dynamic complexation behavior of a monocentric dendrimer with charged terminal groups to a flexible, oppositely charged polyelectrolyte. Three different types of complexes are noted depending upon the solution ionic strength and the sizes of the dendrimer and chain. We find that a dendrimer may encapsulate a chain, a chain and a dendrimer may mutually interpenetrate, or a unique "chain-walking" phenomenon may be observed. The critical conditions for complexation, density profiles of the polyelectrolyte and the dendrimer in the complex, and the curious dynamics observed are discussed. A closed formula is proposed to describe the critical conditions for complexation between a dendrimer and a polyelectrolyte.

Dynamics of Complexation of a Charged Dendrimer by Linear Polyelectrolyte: Computer Modelling

“…The linear-chain motion relative to the dendrimer in a complex has been studied by and was based on the snapshot MC simulation of Welch and Muthukumar [11], analysis. To characterize more quantitatively the motion of a chain relative to a dendrimer in a complex, the correlation functions ) ( 1 t P for unit vectors i c r directed from the dendrimer core to different PE monomers have been calculated, The rotation of a dendrimer as a whole occurs faster than the rotation m the dendrimer becomes slower when PE length increases.…”

“…Theoretical consideration of such systems is restricted by their extreme complexity; in this case the use of computer-simulation methods becomes inevitable. First computer simulations of complexes formed by dendrimers with charged terminal groups and oppositely charged linear chains have been performed by Welch and Muthukumar [11] by Monte Carlo (MC). In their study only equilibrium characteristics, such as radius of gyration and a radial monomer density of the complex have been studied, although some suggestions about the mechanism of the relative-to-the-dendrimer linear-chain motion have been made [11].…”

“…First computer simulations of complexes formed by dendrimers with charged terminal groups and oppositely charged linear chains have been performed by Welch and Muthukumar [11] by Monte Carlo (MC). In their study only equilibrium characteristics, such as radius of gyration and a radial monomer density of the complex have been studied, although some suggestions about the mechanism of the relative-to-the-dendrimer linear-chain motion have been made [11]. Useful information about the dynamics of complexes can be obtained via MD and Brownian dynamics (BD) simulations.…”

Structure and Dynamics of DNA−Dendrimer Complexation: Role of Counterions, Water, and Base Pair Sequence

“…A number of theoretical and computer simulation studies have been reported on structural properties of polyelectrolyte-dendrimer complexation under various conditions [13][14][15][16] .…”

Electrostatics and flexibility drive membrane recognition and early penetration by the antimicrobial peptide dendrimer bH1

“…4 To understand the selective interaction of bH1 with the LPS coated outer membrane of PA versus the eukaryotic cell membrane, we performed all atom molecular dynamics (MD) simulations of the dendrimer [5][6][7][8] interacting with membrane models constituted of a 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) bilayer as a model of the eukaryotic membrane, or of an asymmetric LPS on top of a 1,2-dipalmytoyl-3-phosphatydyl-ethanolamine (DPPE) layer as a model of the PA outer membrane (structure in ESI †). Standard MD protocols were followed using force field parameters and thermally equilibrated coordinates reported for POPC 9a and LPS.…”