Surface-structure-regulated cell-membrane penetration by monolayer-protected nanoparticles (original) (raw)

Cationic Nanoparticles Induce Nanoscale Disruption in Living Cell Plasma Membranes

The Journal of Physical Chemistry B, 2009

It has long been recognized that cationic nanoparticles induce cell membrane permeability. Recently, it has been found that cationic nanoparticles induce the formation and/or growth of nanoscale holes in supported lipid bilayers. In this paper, we show that noncytotoxic concentrations of cationic nanoparticles induce 30-2000 pA currents in 293A (human embryonic kidney) and KB (human epidermoid carcinoma) cells, consistent with a nanoscale defect such as a single hole or group of holes in the cell membrane ranging from 1 to 350 nm 2 in total area. Other forms of nanoscale defects, including the nanoparticle porating agents adsorbing onto or intercalating into the lipid bilayer, are also consistent; although the size of the defect must increase to account for any reduction in ion conduction, as compared to a water channel. An individual defect forming event takes 1-100 ms, while membrane resealing may occur over tens of seconds. Patch-clamp data provide direct evidence for the formation of nanoscale defects in living cell membranes. The cationic polymer data are compared and contrasted with patch-clamp data obtained for an amphiphilic phenylene ethynylene antimicrobial oligomer (AMO-3), a small molecule that is proposed to make well-defined 3.4 nm holes in lipid bilayers. Here, we observe data that are consistent with AMO-3 making ∼3 nm holes in living cell membranes.

Nanoparticle Interaction with Biological Membranes: Does Nanotechnology Present a Janus Face?

Accounts of Chemical Research, 2007

Polycationic organic nanoparticles are shown to disrupt model biological membranes and living cell membranes at nanomolar concentrations. The degree of disruption is shown to be related to nanoparticle size and charge as well as to the phase, fluid liquid crystalline or gel, of the biological membrane. Disruption events on model membranes have been directly imaged using scanning probe microsopy whereas disruption events on living cells have been analyzed using cytosolic enzyme leakage assays, dye diffusion assays, and fluorescence microscopy.

Dynamic Cellular Uptake of Mixed-Monolayer Protected Nanoparticles

Biointerphases, 2012

Nanoparticles (NPs) are gaining increasing attention for potential application in medicine; consequently, studying their interaction with cells is of central importance. We found that both ligand arrangement and composition on gold nanoparticles play a crucial role in their cellular internalization. In our previous investigation, we showed that 66-34OT nanoparticles coated with stripe-like domains of hydrophobic (octanethiol, OT, 34%) and hydrophilic (11-mercaptoundecane sulfonate, MUS, 66%) ligands permeated through the cellular lipid bilayer via passive diffusion, in addition to endo-/pino-cytosis. Here, we show an analysis of NP internalization by DC2.4, 3T3, and HeLa cells at two temperatures and multiple time points. We study four NPs that differ in their surface structures and ligand compositions and report on their cellular internalization by intracellular fluorescence quantification. Using confocal laser scanning microscopy we have found that all three cell types internalize the 66-34OT NPs more than particles coated only with MUS, or particles coated with a very similar coating but lacking any detectable ligand shell structure, or 'striped' particles but with a different composition (34-66OT) at multiple data points. This article is part of the Topical Collection ''In Focus: Nanomedicine''.

Systematic design of cell membrane coating to improve tumor targeting of nanoparticles

Nature Communications

Cell membrane (CM) coating technology is increasingly being applied in nanomedicine, but the entire coating procedure including adsorption, rupture, and fusion is not completely understood. Previously, we showed that the majority of biomimetic nanoparticles (NPs) were only partially coated, but the mechanism underlying this partial coating remains unclear, which hinders the further improvement of the coating technique. Here, we show that partial coating is an intermediate state due to the adsorption of CM fragments or CM vesicles, the latter of which could eventually be ruptured under external force. Such partial coating is difficult to self-repair to achieve full coating due to the limited membrane fluidity. Building on our understanding of the detailed coating process, we develop a general approach for fixing the partial CM coating: external phospholipid is introduced as a helper to increase CM fluidity, promoting the final fusion of lipid patches. The NPs coated with this approac...

Shape and orientation matter for cellular uptake of non-spherical nanoparticles

Nano Letters, 2013

Recent advances in nano-technology have made a whole zoo of particles of different shapes available for applications, but their interaction with biological cells and their toxicity is often not well understood. Experiments have shown that particle uptake by cells is determined by an intricate interplay between physico-chemical particle properties like shape, size, and surface functionalization, but also by membrane properties and particle orientation. Our work provides systematic understanding, based on a mechanical description, for membrane wrapping of nanoparticles, viruses, and bacterial forms. For rod-like particles, we find stable endocytic states with small and high wrapping fraction; an increased aspect ratio is unfavourable for complete wrapping. For high aspect ratios and round tips, the particles enter via a submarine-mode, side-first with their long edge parallel to the membrane. For small aspect ratios and flat tips, the particles enter tip-first via a rocket-mode.