scholarly journals Rapid evaluation of gold nanoparticle–lipid membrane interactions using a lipid/polydiacetylene vesicle sensor

The Analyst ◽  
2020 ◽  
Vol 145 (8) ◽  
pp. 3049-3055
Author(s):  
Congcong Gu ◽  
Yingying Geng ◽  
Feng Zheng ◽  
Vincent M. Rotello
Keyword(s):  
Gold Nanoparticles ◽  
Gold Nanoparticle ◽  
Lipid Membranes ◽  
Lipid Membrane ◽  
Rapid Evaluation ◽  
Membrane Interactions

Lipid/polydiacetylene vesicles serve as a sensor to rapidly measure the interactions between gold nanoparticles and lipid membranes. A colorimetric signal is generated upon membrane disturbance caused by gold nanoparticles.

scholarly journals Lipid Reconstitution-Enabled Formation of Gold Nanoparticle Clusters for Mimetic Cellular Membrane

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Jiyoung Nam ◽  
Yong-Tae Kim ◽  
Aeyeon Kang ◽  
Kook-Han Kim ◽  
KyoRee Lee ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Gold Nanoparticle ◽  
Cellular Uptake ◽  
Lipid Membranes ◽  
Lipid Membrane ◽  
Cellular Membrane ◽  
Phospholipid Bilayers ◽  
Head Group ◽  
Oligomeric State ◽  
Nanoparticle Clusters

Gold nanoparticles (AuNPs) encapsulated within reconstituted phospholipid bilayers have been utilized in various bioapplications due to their improved cellular uptake without compromising their advantages. Studies have proved that clustering AuNPs can enhance the efficacy of theranostic effects, but controllable aggregation or oligomerization of AuNPs within lipid membranes is still challenging. Here, we successfully demonstrate the formation of gold nanoparticle clusters (AuCLs), supported by reconstituted phospholipid bilayers with appropriate sizes for facilitating cellular uptake. Modulation of the lipid membrane curvatures influences not only the stability of the oligomeric state of the AuCLs, but also the rate of cellular uptake. Dynamic light scattering (DLS) data showed that 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE), with its relatively small head group, is crucial for establishing an effective membrane curvature to encapsulate the AuCLs. The construction of phospholipid bilayers surrounding AuCLs was confirmed by analyzing the secondary structure of M2 proteins incorporated in the lipid membrane surrounding the AuCLs. When AuCLs were incubated with cells, accumulated clusters were found inside the cells without the lipids being removed or exchanged with the cellular membrane. We expect that our approach of clustering gold nanoparticles within lipid membranes can be further developed to design a versatile nanoplatform.

scholarly journals Anionic nanoparticle-lipid membrane interactions: the protonation of anionic ligands at the membrane surface reduces membrane disruption

RSC Advances ◽  
2019 ◽  
Vol 9 (25) ◽  
pp. 13992-13997 ◽  
Author(s):  
Sebastian Salassi ◽  
Ester Canepa ◽  
Riccardo Ferrando ◽  
Giulia Rossi
Keyword(s):  
Lipid Membranes ◽  
Au Nanoparticles ◽  
Lipid Membrane ◽  
Membrane Surface ◽  
Membrane Disruption ◽  
Membrane Interactions ◽  
Carboxylate Groups ◽  
Model Lipid Membranes ◽  
Anionic Ligands

The interaction between anionic Au nanoparticles and model lipid membranes is facilitated by the spontaneous protonation of the NP ligand carboxylate groups, COO−˙ → COOH, in the lipid headgroup region.

An analysis of lipid membrane morphology in the presence of coordinate-dependent non-uniformity

2020 ◽  
Vol 26 (1) ◽  
pp. 45-61
Author(s):  
Wenhao Yao ◽  
Chun IL Kim
Keyword(s):  
Analytical Solution ◽  
Boundary Conditions ◽  
Linear Model ◽  
Energy Function ◽  
Lipid Membranes ◽  
Lipid Membrane ◽  
Membrane Interactions ◽  
Equilibrium Equations ◽  
Material Parameters ◽  
Membrane Morphology

A model for the mechanics of lipid membranes with non-uniform (coordinate-dependent) properties is discussed. The coordinate-dependent responses of the membranes are incorporated via the augmented non-uniform energy function and material parameters, which are dependent explicitly on the surface coordinates. We formulate the associated normal and tangential Euler equilibrium equations through which the coordinate-dependent responses of membranes are characterized. The admissible boundary conditions are taken from the existing non-linear model but reformulated and adopted to the present framework. Within the prescription of superposed incremental deformations, a compatible linear model is also formulated, from which a complete analytical solution describing the non-uniform responses of the membrane subjected to substrate–membrane interactions is obtained.

Interference of Gold Nanoparticles with In vitro Endotoxin Detection Assays

2020 ◽  
Vol 16 (2) ◽  
pp. 204-213 ◽  
Author(s):  
Melissa A. Vetten ◽  
Mary Gulumian
Keyword(s):  
Gold Nanoparticles ◽  
Gold Nanoparticle ◽  
Surface Reactivity ◽  
In Vitro Assays ◽  
Limulus Amebocyte Lysate ◽  
Chromogenic Assay ◽  
Nanoparticle Suspensions ◽  
Endotoxin Contamination ◽  
Factor C

Background: Endotoxin-free engineered nanoparticle suspensions are imperative for their successful applications in the field of nanomedicine as well as in the investigations in their toxicity. Gold nanoparticles are known to interfere with various in vitro assays due to their optical properties and potential for surface reactivity. In vitro endotoxin testing assays are known to be susceptible to interference caused by the sample being tested. Objective: This study aimed to identify a preferred assay for the testing of endotoxin contamination in gold nanoparticle suspensions. Methods: The interference by gold nanoparticles on three assays namely, the commonly used limulus amebocyte lysate chromogenic assay, the limulus amebocyte lysate gel-clot method, and the less common recombinant Factor C (rFC) assay, was tested. Results: Possible interference could be observed with all three assays. The interference with the absorbance- based chromogenic assay could not be overcome by dilution; whilst the qualitative nature of the gel-clot assay excluded the possibility of distinguishing between a false positive result due to enhancement of the sensitivity of the assay, and genuine endotoxin contamination. However, interference with the rFC assay was easily overcome through dilution. Conclusion: The rFC assay is recommended as an option for endotoxin contamination detection in gold nanoparticle suspensions.

scholarly journals Electrochemical Properties of Lipid Membranes Self-Assembled from Bicelles

Membranes ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 11
Author(s):  
Damian Dziubak ◽  
Kamil Strzelak ◽  
Slawomir Sek
Keyword(s):  
Electrochemical Properties ◽  
Self Assembly ◽  
Lipid Membranes ◽  
Lipid Membrane ◽  
Membrane Resistance ◽  
Electrochemical Characteristics ◽  
Freeze Thaw ◽  
Lipid Films ◽  
Supported Lipid Membranes

Supported lipid membranes are widely used platforms which serve as simplified models of cell membranes. Among numerous methods used for preparation of planar lipid films, self-assembly of bicelles appears to be promising strategy. Therefore, in this paper we have examined the mechanism of formation and the electrochemical properties of lipid films deposited onto thioglucose-modified gold electrodes from bicellar mixtures. It was found that adsorption of the bicelles occurs by replacement of interfacial water and it leads to formation of a double bilayer structure on the electrode surface. The resulting lipid assembly contains numerous defects and pinholes which affect the permeability of the membrane for ions and water. Significant improvement in morphology and electrochemical characteristics is achieved upon freeze–thaw treatment of the deposited membrane. The lipid assembly is rearranged to single bilayer configuration with locally occurring patches of the second bilayer, and the number of pinholes is substantially decreased. Electrochemical characterization of the lipid membrane after freeze–thaw treatment demonstrated that its permeability for ions and water is significantly reduced, which was manifested by the relatively high value of the membrane resistance.

scholarly journals Interactions of Linear Analogues of Battacin with Negatively Charged Lipid Membranes

Membranes ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 192
Author(s):  
Kinga Burdach ◽  
Dagmara Tymecka ◽  
Aneta Urban ◽  
Robert Lasek ◽  
Dariusz Bartosik ◽  
...  
Keyword(s):  
Lipid Membranes ◽  
Liquid Crystalline ◽  
Lipid Membrane ◽  
Attenuated Total Reflection ◽  
Gram Positive ◽  
Insertion Depth ◽  
Force Microscopy ◽  
Acyl Chains ◽  
Hydrophobic Portion ◽  
Membrane Fluidization

The increasing resistance of bacteria to available antibiotics has stimulated the search for new antimicrobial compounds with less specific mechanisms of action. These include the ability to disrupt the structure of the cell membrane, which in turn leads to its damage. In this context, amphiphilic lipopeptides belong to the class of the compounds which may fulfill this requirement. In this paper, we describe two linear analogues of battacin with modified acyl chains to tune the balance between the hydrophilic and hydrophobic portion of lipopeptides. We demonstrate that both compounds display antimicrobial activity with the lowest values of minimum inhibitory concentrations found for Gram-positive pathogens. Therefore, their mechanism of action was evaluated on a molecular level using model lipid films mimicking the membrane of Gram-positive bacteria. The surface pressure measurements revealed that both lipopeptides show ability to bind and incorporate into the lipid monolayers, resulting in decreased ordering of lipids and membrane fluidization. Atomic force microscopy (AFM) imaging demonstrated that the exposure of the model bilayers to lipopeptides leads to a transition from the ordered gel phase to disordered liquid crystalline phase. This observation was confirmed by attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR) results, which revealed that lipopeptide action causes a substantial increase in the average tilt angle of lipid acyl chains with respect to the surface normal to compensate for lipopeptide insertion into the membrane. Moreover, the peptide moieties in both molecules do not adopt any well-defined secondary structure upon binding with the lipid membrane. It was also observed that a small difference in the structure of a lipophilic chain, altering the balance between hydrophobic and hydrophilic portion of the molecules, results in different insertion depth of the active compounds.

scholarly journals CRISPR/Cas12a-mediated gold nanoparticle aggregation for colorimetric detection of SARS-CoV-2

2021 ◽  
Author(s):  
Yiren Cao ◽  
Jinjun Wu ◽  
Bo Pang ◽  
Hongquan Zhang ◽  
X. Chris Le
Keyword(s):  
Gold Nanoparticles ◽  
Gold Nanoparticle ◽  
Colorimetric Detection ◽  
Isothermal Amplification ◽  
Nanoparticle Aggregation ◽  
Cleavage Activity ◽  
Gold Nanoparticle Aggregation

The trans-cleavage activity of the target-activated CRISPR-Cas12a liberated an RNA crosslinker from a molecular transducer, which facilitated assembly of gold nanoparticles. Integration of the molecular transducer with isothermal amplification and...

Fluorescence biosensor for Salmonella typhimurium detection in food based on nano-self-assembly of alendronic acid modified upconversion and gold nanoparticles

2021 ◽  
Author(s):  
Min Chen ◽  
Leiqing Pan ◽  
K. Tu
Keyword(s):  
Gold Nanoparticles ◽  
Salmonella Typhimurium ◽  
Gold Nanoparticle ◽  
Alendronic Acid ◽  
Self Assembly ◽  
Upconversion Nanoparticles ◽  
Fluorescent Biosensor ◽  
Fluorescence Biosensor

A simple and quick responsive fluorescent biosensor for Salmonella typhimurium detection based on the recognition of aptamer coupled with alendronic acid (ADA)@upconversion nanoparticles (UCNPs) and gold nanoparticle (AuNPs) has been...

scholarly journals Enhanced Extracellular Synthesis of Gold Nanoparticles by Soluble Extracts from Escherichia coli Transformed with Rhizobium tropici Phytochelatin Synthase Gene

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 472
Author(s):  
Qunying Yuan ◽  
Manjula Bomma ◽  
Zhigang Xiao
Keyword(s):  
Gold Nanoparticles ◽  
Gold Nanoparticle ◽  
Synthesis Method ◽  
Nanoparticle Synthesis ◽  
Morphological Properties ◽  
Phytochelatin Synthase ◽  
Rhizobium Tropici ◽  
Whole Cells ◽  
E Coli ◽  
Recombinant Cells

Phytochelatins, the enzymatic products of phytochelatin synthase, play a principal role in protecting the plants from heavy metal and metalloid toxicity due to their ability to scavenge metal ions. In the present study, we investigated the capacity of soluble intracellular extracts from E. coli cells expressing R. tropici phytochelatin synthase to synthesize gold nanoparticle. We discovered that the reaction mediated by soluble extracts from the recombinant E. coli cells had a higher yield of gold nanoparticles, compared to that from the control cells. The compositional and morphological properties of the gold nanoparticles synthesized by the intracellular extracts from recombinant cells and control cells were similar. In addition, this extracellular nanoparticle synthesis method produced purer gold nanoparticles, avoiding the isolation of nanoparticles from cellular debris when whole cells are used to synthesize nanoparticles. Our results suggested that phytochelatins can improve the efficiency of gold nanoparticle synthesis mediated by bacterial soluble intracellular extracts, and the potential of extracellular nanoparticle synthesis platform for the production of nanoparticles in large quantity and pure form is worth further investigation.

scholarly journals Enhanced enzymatic activity from phosphotriesterase trimer gold nanoparticle bioconjugates for pesticide detection

The Analyst ◽  
2017 ◽  
Vol 142 (17) ◽  
pp. 3261-3271 ◽  
Author(s):  
John A. Hondred ◽  
Joyce C. Breger ◽  
Nate T. Garland ◽  
Eunkeu Oh ◽  
Kimihiro Susumu ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Enzymatic Activity ◽  
Gold Nanoparticle ◽  
Pesticide Detection

A significant enzymatic enhancement of phosphotriesterase has been demonstrated when immobilized on various sized gold nanoparticles.

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