Electric double layer electrostatics of lipid‐bilayer‐encapsulated nanoparticles: Toward a better understanding of protocell electrostatics

Abstract

Lipid-bilayer-encapsulated nanoparticles (LBLENPs) or NP-supported LBL systems, such as protocells (which are lipid bilayer encapsulated mesoporous silica nanoparticles or MSNPs) have received extensive attention for applications like targeted drug and gene deliveries, multimodal diagnostics, characterization of membrane-geometry sensitive molecules, etc. Very often electrostatic-mediated interactions have been hypothesized to play key roles in the functioning of these LBLENPs. Despite that, very little has been done to theoretically quantify the fundamental electric double layer (EDL) electrostatics of such LBLENPs. In this study, we develop an EDL theory to describe the electrostatics of such LBLENPs. We show that the electrostatics is a manifestation of the charged/dielectric nature of the NP, LBL structure and charging, and the ionic environment in which the LBLENPs are present. We also establish that for certain conditions of charging of the NP one witnesses a most remarkable charge inversion like electrostatics within the LBL membrane or the NP itself. We anticipate that our findings will provide an extremely useful platform for better understanding the fabrication and functioning of such LBLENPs and discuss examples where our theory can be useful.

Voltammetric pH Measurements Using Azure A-Containing Layer-by-Layer Film Immobilized Electrodes

“…The multilayer thin films composed of functional organic molecules, enzymes, and lectins also respond to substrates, such as pH [ 21 , 22 ], electrical potential [ 23 ], glucose, lactate, and hydrogen peroxide [ 24 , 25 , 26 ]. Such functional multilayer thin films could be useful for separation and purification [ 27 , 28 ], sensors [ 29 , 30 ], and drug delivery systems [ 31 , 32 , 33 , 34 ].…”

Electrophoresis of Liquid-Layer Coated Particles: Impact of Ion Partitioning and Ion Steric Effects

“…Such choice of interfacial charge is reasonable for the cellmembrane-coated NPs. 27 We observe that the interfacial potential y 0 and the electrophoretic mobility μ E /μ 0 increases with the increase in concentration of additional mobile ions across the liquid layer and its effect is prominent for low electrolyte concentration. On the other hand, for electrolytes with high concentration, the shielding effect has a prominent role to screen the interfacial surface charge, which further reduces the effective electric potential along the surface of the liquid layer.…”

“…The interfacial charge is varied, changing the parameter S from 500 Å 2 to 50 000 Å 2 , which results in the range for interfacial charge σ from 0.032 C/m 2 to 0.00032 C/m 2 . Such choice of interfacial charge is reasonable for the cell-membrane-coated NPs . We observe that the interfacial potential y 0 and the electrophoretic mobility μ E /μ 0 increases with the increase in concentration of additional mobile ions across the liquid layer and its effect is prominent for low electrolyte concentration.…”

“…Honig et al 25 and McLaughlin 26 made exhaustive studies on the membrane potential of lipid bilayers. Recently, Jing and Das 27 studied the electrostatic behavior of lipid bilayer-coated functionalized NPs. In all these articles, the studies are restricted only to the electrostatics of core−shell functionalized NPs with a peripheral shell as a lipid layer or cell membrane.…”

Ion partitioning effect on the electrostatic interaction between two charged soft surfaces

“…However, those investigations have addressed mainly charged particles without any polymer coating layer [17]. Nowadays, polyelectrolyte grafted nanochannels (also called soft nanochannels) were widely studied for the development of nanofluidics achieving diode-like behavior, energy conversion and the detection of biomolecules [18,19,20,21,22,23], while polyelectrolyte adsorbed particles (also called soft particles) were employed for controlling colloidal stability and drug delivery [24,25,26,27,28]. All Email address: js.sin@ryongnamsan.edu.kp (Jun-Sik Sin) the studies confirmed that compared to conventional colloidal particles and nanochannels, soft colloidal particles and soft nanochannels can support excellent functions, respectively.…”