Simulation Results Small Nanoparticle Near a Lipid Bilayer

Simulation Results Small Nanoparticle Near a Lipid Bilayer 

We first consider uncharged ( hydrophobic ) nanoparticles. In this case, the particle is hkely to be absorbed into the membrane, swelling it and effectively cleaving its internal hydrophobic bilayer into two. This mechanism is somewhat similar to the selective swelling of block copolymer lamellar domains by nanoparticles [83-84, 88, 91, 92]. Because of the hydrophobic nature of the particle surface, the particle breaks up the bilayer to increase its contacts with the lipophilic surfactant tails, and thereby minimize its surface tension. Such behavior is consistent with the results of recent experiments conducted Banaszak Holl, Orr et al. [17-19], which showed that charge-neutral PAMAM dendrimers G5-Ac adsorb to the existing supported lipid bilayers-the layers thicken, but no new holes are formed. 

The behavior of the membrane changes completely in the presence of strongly charged nanoparticles. Because of the strong attraction of the head-groups to the particle surface, the preferential phospholipid arrangement now would be to form 

From the above analysis, it follows that uncharged or hydrophobically modified nanoparticles can incorporate into cell membranes, resulting in membrane swelling. On the other hand, strongly charged or more hydrophilic nanoparticles can pull the phospholipids away from the membrane, forming a hybrid micelle (particle as core, phospholipid bilayer as shell). This process can lead to the rupture of the original membrane and formation of nanosized holes. 

UntQ now, this analysis has focused on nanoparticles with Rj, 1-4nm. But what might be expected if the nanopartide size were to be increased We believe that the same trends would be observed for slightly larger sizes Rp 5-10nm), where particle size is still comparable to the membrane thickness. It could be 

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