Driving Adsorbed Gold Nanoparticle Assembly by Merging Lipid Gel/Fluid Interfaces

Wang, Feng; Curry, Dennis E.; Liu, Juewen

doi:10.1021/acs.langmuir.5b03606

Cited by 41 publications

(73 citation statements)

References 29 publications

(57 reference statements)

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“…We conducted the measurements of CTB binding to DMPC model membranes with 1 mol% GM 1 and GM 1 :GM 2 mixture (1 mol%:1 mol%) at 15 °C and 45 °C. In the DOPC bilayer, which has transition temperature at −20 °C,[32] the cooperativity between GM 1 and GM 2 at 15 °C was quite similar to what we obtained at room temperature, which implies that such a temperature change does not alter CTB binding much (Fig 4). However, the diffusion of glycolipids in DMPC gel phase is two orders of magnitude lower when compared to the fluidic DMPC membrane.…”

Section: Resultssupporting

confidence: 81%

Hetero-multivalent binding of cholera toxin subunit B with glycolipid mixtures

Krishnan

Singla

Lee

et al. 2017

Colloids and Surfaces B: Biointerfaces

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GM1 has generally been considered as the major receptor that binds to cholera toxin subunit B (CTB) due to its low dissociation constant. However, using a unique nanocube sensor technology, we have shown that CTB can also bind to other glycolipid receptors, fucosyl-GM1 and GD1b. Additionally, we have demonstrated that GM2 can contribute to CTB binding if present in a glycolipid mixture with a strongly binding receptor (GM1/fucosyl-GM1/GD1b). This hetero-multivalent binding result was unintuitive because the interaction between CTB and pure GM2 is negligible. We hypothesized that the reduced dimensionality of CTB-GM2 binding events is a major cause of the observed CTB binding enhancement. Once CTB has attached to a strong receptor, subsequent binding events are confined to a 2D membrane surface. Therefore, even a weak GM2 receptor could now participate in second or higher binding events because its surface reaction rate can be up to 104 times higher than the bulk reaction rate. To test this hypothesis, we altered the surface reaction rate by modulating the fluidity and heterogeneity of the model membrane. Decreasing membrane fluidity reduced the binding cooperativity between GM2 and a strong receptor. Our findings indicated a new protein-receptor binding assay, that can mimic complex cell membrane environment more accurately, is required to explore the inherent hetero-multivalency of the cell membrane. We have thus developed a new membrane perturbation protocol to efficiently screen receptor candidates involved in hetero-multivalent protein binding.

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Section: Resultssupporting

confidence: 81%

Hetero-multivalent binding of cholera toxin subunit B with glycolipid mixtures

Krishnan

Singla

Lee

et al. 2017

Colloids and Surfaces B: Biointerfaces

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“…22 We observed such a phenomenon with gold nanoparticles. 43,48 In that case, we attributed it to the strong van der Waals force between gold and liposome. Here, the CeO2 NPs were brought very close to the liposome surface by the lipid phosphate interaction.…”

mentioning

confidence: 92%

“…Once adsorbed, the liposome becomes stable again. 22,43,48,49 The DPPC liposome is already in the gel phase, and thus adding nanoceria would not induce the phase transition and thus no leakage took place. While this is a model study performed in a reduced physical system, it still has interesting biological implications.…”

mentioning

confidence: 99%

Adsorption of Nanoceria by Phosphocholine Liposomes

Liu

2016

Langmuir

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Nanoceria (CeO2 nanoparticle) possesses a number of enzyme-like activities. In particular, it scavenges reactive oxygen species (ROS) leading in vitro and in vivo anti-oxidation studies. An important aspect of fundamental physical understanding is its interaction with lipid membranes, the man component of the cell membrane. In this work, adsorption of nanoceria onto phosphocholine (PC) liposomes was performed. PC lipids are the main constituent of the cell outer membrane. Using fluorescence quenching assay, nanoceria adsorption isotherm was determined at various pH's and ionic strengths. A non-Langmuir isotherm occurred at pH 4.0 due to lateral electrostatic repulsion among adsorbed cationic nanoceria. The phosphate group in the PC lipid is mainly responsible for the interaction, and adsorbed nanoceria can be displaced by free inorganic phosphate. The tendency of the system to form large aggregates is a function of pH and the concentration of nanoceria, attributable to nanoceria being positively charged at pH 4 and neural at physiological pH. Calcein leakage test indicates that nanoceria induces liposome leakage due to transient lipid phase transition, and cryo-TEM indicates that the overall shape of the liposome is retained although deformation is still observed. This study provides fundamental biointerfacial information at a molecular level regarding the interaction of nanoceria and model cell membranes.3

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“…11 However, as the nanoparticle travels in the body through different compartments with different composition and pH, initially adsorbed moieties are progressively replaced by proteins of higher affinity. 12 As a result, incorporation of functional organic moieties via stronger (thiol 13 or carbenebased 14,15 ) bonding is preferred. There is thus a need for functionalized Au NPs exhibiting strong attachment of the ligand to the NP and the attachment of species in solution to the functional end of the ligandwhich may drive self-assembly.…”

Section: Introductionmentioning

confidence: 99%