TiO2 nanoparticle interactions with supported lipid membranes – an example of removal of membrane patches

RSC Advances ◽  
2016 ◽  
Vol 6 (94) ◽  
pp. 91102-91110 ◽  
Author(s):  
Fang Zhao ◽  
Jenny Perez Holmberg ◽  
Zareen Abbas ◽  
Rickard Frost ◽  
Tora Sirkka ◽  
...  
Keyword(s):  
Lipid Membranes ◽  
Biological Systems ◽  
Tio2 Nanoparticle ◽  
Engineered Nanoparticles ◽  
Model Systems ◽  
Structure Activity ◽  
Nanoparticle Interactions ◽  
Nanoparticle Structure ◽  
Supported Lipid Membranes ◽  
Different Levels

Different levels of model systems are needed for effect studies of engineered nanoparticles and the development of nanoparticle structure–activity relationships in biological systems.

Nanotoxicology in the Skin: How Deep is the Issue?

Nano LIFE ◽  
2014 ◽  
Vol 04 (01) ◽  
pp. 1440004 ◽  
Author(s):  
Yun Zhao ◽  
Kee Woei Ng
Keyword(s):  
Cell Death ◽  
Biological Systems ◽  
Skin Barrier ◽  
Engineered Nanoparticles ◽  
Current Understanding ◽  
Intact Skin ◽  
Knowledge Gaps ◽  
Skin Exposure ◽  
Skin Cells ◽  
Nanoparticle Interactions

Nanotoxicology is a concern. While skin exposure is generally perceived as less hazardous than inhalation or ingestion of engineered nanoparticles, there remain significant knowledge gaps in the topic to suggest greater caution in making a conclusion. Penetration of nanoparticles across an intact skin barrier is low. However, the verdict is still out on how this will change in situations where the skin barrier is compromised. Many studies on the interaction of nanoparticles with biological systems including skin cells have been reported. Under different scenarios, nanoparticles commonly found in topical skin products have been shown to be capable of exerting a variety of toxicological influences. These influences include causing cell death, stress, inflammation and damage to DNA. While alarming, it should also be noted that there remains much confusion and contradiction in the literature due to the complexity of studying cell–nanoparticle interactions. This review aims to provide a concise perspective on our current understanding of nanotoxicology in the skin, and identify the knowledge gaps where research efforts may be focused to help clarify the uncertainties in the field.

Radiolabelling of TiO2 Nanoparticle Libraries for Toxicological Investigations

2009 ◽  
Vol 1209 ◽  
Author(s):  
Anthony W. Musumeci ◽  
Lawrence R Gahan ◽  
Tijana Rajh ◽  
Darren J Martin ◽  
Suzanne V Smith
Keyword(s):  
Titanium Dioxide ◽  
Biological Systems ◽  
Tio2 Nanoparticle ◽  
Robust Methods ◽  
Nanoparticle Interactions ◽  
Highly Sensitive ◽  
Gamma Emitter

AbstractTo further our understanding of nanoparticle interactions with biological systems, it is important that highly sensitive, reliable and robust methods for labelling particles are established. We report here the application of a series of bi-functional cage ligands to radiolabel a range (i.e. shapes and sizes) of titanium dioxide (TiO2) particles. The cages were covalently attached to the surface of the particles via the use of a dopac derivative and then radiolabelled with a gamma emitting radioisotope. The final radiolabelled nanoparticles proved to be stable in solution and the method easy and robust. The application of a gamma emitter allows the radiolabelled particles to be tracked in vivo and in the environment.

Simulation Modeling of Supported Lipid Membranes – A Review

2014 ◽  
Vol 14 (5) ◽  
pp. 617-623 ◽  
Author(s):  
Michael Hirtz ◽  
Naresh Kumar ◽  
Lifeng Chi
Keyword(s):  
Lipid Membranes ◽  
Simulation Modeling ◽  
Supported Lipid Membranes

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 Quantitative linear dichroism imaging of molecular processes in living cells made simple by open software tools

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Alexey Bondar ◽  
Olga Rybakova ◽  
Josef Melcr ◽  
Jan Dohnálek ◽  
Petro Khoroshyy ◽  
...  
Keyword(s):  
Biological Systems ◽  
Linear Dichroism ◽  
Quantitative Information ◽  
Living Cells ◽  
Software Tools ◽  
Model Systems ◽  
Membrane Properties ◽  
Polarization Microscopy ◽  
Molecular Processes ◽  
Wide Range

AbstractFluorescence-detected linear dichroism microscopy allows observing various molecular processes in living cells, as well as obtaining quantitative information on orientation of fluorescent molecules associated with cellular features. Such information can provide insights into protein structure, aid in development of genetically encoded probes, and allow determinations of lipid membrane properties. However, quantitating and interpreting linear dichroism in biological systems has been laborious and unreliable. Here we present a set of open source ImageJ-based software tools that allow fast and easy linear dichroism visualization and quantitation, as well as extraction of quantitative information on molecular orientations, even in living systems. The tools were tested on model synthetic lipid vesicles and applied to a variety of biological systems, including observations of conformational changes during G-protein signaling in living cells, using fluorescent proteins. Our results show that our tools and model systems are applicable to a wide range of molecules and polarization-resolved microscopy techniques, and represent a significant step towards making polarization microscopy a mainstream tool of biological imaging.

Specific Capacitance of Metal Supported Lipid Membranes

1998 ◽  
Vol 10 (5) ◽  
pp. 295-302 ◽  
Author(s):  
Victor I. Passechnik ◽  
Tibor Hianik ◽  
Sergey A. Ivanov ◽  
Branislav Sivak
Keyword(s):  
Specific Capacitance ◽  
Lipid Membranes ◽  
Supported Lipid Membranes

Visual control of orientation behaviour in the fly: Part I. A quantitative analysis

1976 ◽  
Vol 9 (3) ◽  
pp. 311-375 ◽  
Author(s):  
Werner Reichardt ◽  
Tomaso Poggio
Keyword(s):  
Information Processing ◽  
Quantitative Analysis ◽  
Visual System ◽  
Sensory Information ◽  
Model Systems ◽  
Suitable Model ◽  
Logical Organization ◽  
Integrative Level ◽  
Processing Properties ◽  
Different Levels

An understanding of sensory information processing in the nervous system will probably require investigations with a variety of ‘model’ systems at different levels of complexity.Our choice of a suitable model system was constrained by two conflicting requirements: on one hand the information processing properties of the system should be rather complex, on the other hand the system should be amenable to a quantitative analysis. In this sense the fly represents a compromise.In these two papers we explore how optical information is processed by the fly's visual system. Our objective is to unravel the logical organization of the fly's visual system and its underlying functional and computational principles. Our approach is at a highly integrative level. There are different levels of analysing and ‘understanding’ complex systems, like a brain or a sophisticated computer.

scholarly journals Supervised Learning Model Predicts Protein Adsorption to Nanotubes

2021 ◽  
Author(s):  
Rebecca L Pinals ◽  
Nicholas Ouassil ◽  
Jackson Travis Del Bonis-O'Donnell ◽  
Jeffrey W Wang ◽  
Markita P Landry
Keyword(s):  
Amino Acids ◽  
Protein Adsorption ◽  
Biological Systems ◽  
Protein Corona ◽  
Engineered Nanoparticles ◽  
Mass Spectrometry Data ◽  
In Vitro Synthesis ◽  
Intractable Problem

Engineered nanoparticles are advantageous for numerous biotechnology applications, including biomolecular sensing and delivery. However, testing the compatibility and function of nanotechnologies in biological systems requires a heuristic approach, where unpredictable biofouling often prevents effective implementation. Such biofouling is the result of spontaneous protein adsorption to the nanoparticle surface, forming the "protein corona" and altering the physicochemical properties, and thus intended function, of the nanotechnology. To better apply engineered nanoparticles in biological systems, herein, we develop a random forest classifier (RFC) trained with proteomic mass spectrometry data that identifies which proteins adsorb to nanoparticles. We model proteins that populate the corona of a single-walled carbon nanotube (SWCNT)-based optical nanosensor. We optimize the classifier and characterize the classifier performance against other models. To evaluate the predictive power of our model, we then apply the classifier to rapidly identify and experimentally validate proteins with high binding affinity to SWCNTs. Using protein properties based solely on amino acid sequence, we further determine protein features associated with increased likelihood of SWCNT binding: proteins with high content of solvent-exposed glycine residues and non-secondary structure-associated amino acids. Furthermore, proteins with high leucine residue content and beta-sheet-associated amino acids are less likely to form the SWCNT protein corona. The classifier presented herein provides an important tool to undertake the otherwise intractable problem of predicting protein-nanoparticle interactions, which is needed for more rapid and effective translation of nanobiotechnologies from in vitro synthesis to in vivo use.

scholarly journals Elucidating the mechanism of cellular uptake of fullerene nanoparticles

2021 ◽  
Vol 27 (2) ◽  
pp. 200658-0
Author(s):  
Yeonjeong Ha ◽  
Xianzhe Wang ◽  
Howard M. Liljestrand ◽  
Jennifer A. Maynard ◽  
Lynn E. Katz
Keyword(s):  
Active Transport ◽  
Cellular Uptake ◽  
Lipid Membranes ◽  
Culture Media ◽  
Passive Diffusion ◽  
Engineered Nanoparticles ◽  
Metabolic Inhibitors ◽  
Representative Cell ◽  
Fullerene Concentration ◽  
Microtubule Transport

Understanding the molecular interactions between biological cells and engineered nanoparticles is a key to evaluating potential toxicities to humans and the environment. This study developed a method to determine the mechanisms by which fullerene aggregates are distributed into a representative cell line, human intestinal Caco-2 cells. First, we determined that the presence of fetal bovine serum (FBS) in the cell culture media changes the particle characteristics and inhibits particle adsorptions onto cell surfaces. Second, significantly lower amounts of fullerene were internalized at 4°C, a temperature at which active transport mechanisms are effectively impeded, than at 37°C. Third, metabolic inhibitors of active transport and a microtubule transport inhibitor decreased fullerene uptake at 37°C. Fourth, cellular uptake of fullerene increased with increasing fullerene concentration, suggesting that passive diffusion into lipid membranes contributed to uptake over the broad concentration range used in this study. Together, these results indicate fullerene transport into cells occurs via two mechanisms: passive diffusion across the lipid bilayer and active transport including microtubule involved endocytosis. The results also suggest that simple physical-chemical partitioning models do not fully describe fullerene uptake, and instead, active transport models are also required to estimate the cellular uptake and toxicity of fullerene.

scholarly journals Membrane insertion of the N-terminal α-helix of equinatoxin II, a sea anemone cytolytic toxin

2004 ◽  
Vol 384 (2) ◽  
pp. 421-428 ◽  
Author(s):  
Ion GUTIÉRREZ-AGUIRRE ◽  
Ariana BARLIČ ◽  
Zdravko PODLESEK ◽  
Peter MAČEK ◽  
Gregor ANDERLUH ◽  
...  
Keyword(s):  
Lipid Membranes ◽  
Lipid Membrane ◽  
Model Systems ◽  
Tryptophan Residue ◽  
Sea Anemones ◽  
Fluorescence Measurements ◽  
Tryptophan Residues ◽  
Equinatoxin Ii ◽  
Α Helix ◽  
Pore Forming Proteins

Equinatoxin II (Eqt-II) is a member of the actinoporins, a unique family of cytotoxins comprising 20 kDa pore-forming proteins isolated from sea anemones. Actinoporins bind preferentially to lipid membranes containing sphingomyelin, and create cation-selective pores by oligomerization of three to four monomers. Previous studies have shown that regions of Eqt-II crucial for its cytolytic mechanism are an exposed aromatic cluster and the N-terminal region containing an amphipathic α-helix. In the present study, we have investigated the transfer of the N-terminal α-helix into the lipid membrane by the use of three mutants containing an additional tryptophan residue in different positions within the amphipathic α-helix (Ile18→Trp, Val22→Trp and Ala25→Trp). The interaction of the mutants with different model systems, such as lipid monolayers, erythrocytes and ghost membranes, was extensively characterized. Intrinsic fluorescence measurements and the use of vesicles containing brominated phospholipids indicated a deep localization of the N-terminal amphipathic helix in the lipid bilayer, except for the case of Val22→Trp. This mutant is stabilized in a state immediately prior to final pore formation. The introduction of additional tryptophan residues in the sequence of Eqt-II has proved to be a suitable approach to monitor the new environments that surround defined regions of the molecule upon membrane interaction.

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