Atomic force microscopy as a tool to study the adsorption of DNA onto lipid interfaces

Luque-Caballero, Germán; Maldonado-Valderrama, Julia; Quesada‐Pérez, Manuel

doi:10.1002/jemt.22654

Cited by 7 publications

(6 citation statements)

References 61 publications

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“…The novelty of the system under investigation lies in the ability to tune the solubility of a synthetic polyelectrolyte by changing the ionic strength of the subphase to examine interactions of either its adsorbed or spread layers with a natural polyelectrolyte. This feature strongly distinguishes this system from the usually studied mixed layers of phospholipids and DNA where the lipid solubility is negligible as compared with that of PDAHMAC [ 3 , 12 , 13 , 15 , 16 , 17 , 19 , 20 , 21 , 22 , 23 , 26 , 32 , 33 , 34 ]. The DNA–lipid interactions are mainly considered to be of electrostatic nature, and DNA is attracted to the layer of positively charged groups of the lipid and can penetrate it [ 20 , 21 , 22 , 34 , 51 ].…”

Section: Discussionmentioning

confidence: 99%

“…Research into the formation of 2D nanostructures attracts a lot of attention [ 1 , 2 , 9 , 10 ]. While many of the systems investigated involve lipid monolayers [ 11 , 12 , 13 , 15 , 16 , 17 , 19 , 20 , 21 , 22 , 23 , 26 , 34 , 51 ], the present work has adopted a novel approach to confine a spread polyelectrolyte film on a subphase of elevated ionic strength to gain insight into the mechanism of DNA interactions that determine surface aggregate formation. The results have shown that various surface properties including the dynamic surface elasticity, surface tension and surface excess exhibit a long induction period only if the initial surface excess of the surface film is in a quasiplateau region and not if the initial surface excess is lower.…”

Section: Discussionmentioning

confidence: 99%

“…DNA binding to Langmuir monolayers of lipids and cationic surfactants has been studied for more than twenty years mainly due to a sustained interest in the non-viral gene delivery and construction of DNA-based electronic devices [ 3 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 ]. It has been shown that DNA conformations in the surface layer largely depend on the properties of the substances used to form a monolayer.…”

Section: Introductionmentioning

confidence: 99%

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DNA Interaction with a Polyelectrolyte Monolayer at Solution—Air Interface

et al. 2021

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The formation of ordered 2D nanostructures of double stranded DNA molecules at various interfaces attracts more and more focus in medical and engineering research, but the underlying intermolecular interactions still require elucidation. Recently, it has been revealed that mixtures of DNA with a series of hydrophobic cationic polyelectrolytes including poly(N,N-diallyl-N-hexyl-N-methylammonium) chloride (PDAHMAC) form a network of ribbonlike or threadlike aggregates at the solution—air interface. In the present work, we adopt a novel approach to confine the same polyelectrolyte at the solution—air interface by spreading it on a subphase with elevated ionic strength. A suite of techniques–rheology, microscopy, ellipsometry, and spectroscopy–are applied to gain insight into main steps of the adsorption layer formation, which results in non-monotonic kinetic dependencies of various surface properties. A long induction period of the kinetic dependencies after DNA is exposed to the surface film results only if the initial surface pressure corresponds to a quasiplateau region of the compression isotherm of a PDAHMAC monolayer. Despite the different aggregation mechanisms, the micromorphology of the mixed PDAHMAC/DNA does not depend noticeably on the initial surface pressure. The results provide new perspective on nanostructure formation involving nucleic acids building blocks.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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DNA Interaction with a Polyelectrolyte Monolayer at Solution—Air Interface

et al. 2021

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“…DNA adsorption onto likely charged lipid surfaces mediated by divalent cations can also take place. 47 ] The propensity of membrane wrapping around the particles scales with their mutual attraction strength, see ref. 18 and 48-60 for a theoretical viewpoint.…”

Section: Introductionmentioning

confidence: 99%

Interactions of rod-like particles on responsive elastic sheets

et al. 2016

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What are the physical laws of the mutual interactions of objects bound to cell membranes, such as various membrane proteins or elongated virus particles? To rationalise this, we here investigate by extensive computer simulations mutual interactions of rod-like particles adsorbed on the surface of responsive elastic two-dimensional sheets. Specifically, we quantify sheet deformations as a response to adhesion of such filamentous particles. We demonstrate that tip-to-tip contacts of rods are favoured for relatively soft sheets, while side-by-side contacts are preferred for stiffer elastic substrates. These attractive orientation-dependent substrate-mediated interactions between the rod-like particles on responsive sheets can drive their aggregation and self-assembly. The optimal orientation of the membrane-bound rods is established via responding to the elastic energy profiles created around the particles. We unveil the phase diagramme of attractive-repulsive rod-rod interactions in the plane of their separation and mutual orientation. Applications of our results to other systems featuring membrane-associated particles are also discussed.

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“…Accordingly, in order to understand the molecular mechanism behind the CHOL-lipid interactions mediated by cations, we will compare our results with previously obtained in the literature. For instance, the effect of Ca 2+ on π-A isotherms of DPPC/DPPS 4:1 monolayers was studied at the air-water interface [48][49][50].…”

Section: Discussionmentioning

confidence: 99%

Condensation of Model Lipid Films by Cholesterol: Specific Ion Effects

2019

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The condensing effect and the ability of cholesterol (CHOL) to induce ordering in lipid films is a question of relevance in biological membranes such as the milk fat globule membrane (MFGM) in which the amount of CHOL influences the phase separation and mechanical resistance to rupture of coexisting phases relevant to emulsified food systems. Here, we study the effect of different salts (NaCl, CaCl 2 , MgCl 2 , LaCl 3 ) on monolayers made of a model mixture of lipids (DPPC:DPPS 4:1) and CHOL. To this end, we apply Langmuir Film Balance to report a combined analysis of surface pressure-area (π-A) and surface potential-area (∆V-A) isotherms along with Micro-Brewster Angle Microscopy (Micro-BAM) images of the monolayers in the presence of the different electrolytes. We show that the condensation of lipid by CHOL depends strongly on the nature of the ions by altering the shape and features of the π-A isotherms. ∆V-A isotherms provide further detail on the ion specific interactions with CHOL. Our results show that the condensation of lipids in the presence of CHOL depends on the combined action of ions and CHOL, which can alter the physical state of the monolayer.Coatings 2019, 9, 474 2 of 16 strength of the membrane and inducing a non-ideal behavior in mixed systems (known as condensing effect) [9,13]. This non-ideal behavior was firstly observed by Leathes in 1925 who studied mixtures of CHOL and egg lecithin monolayers [14]. Therein, it was proved that the average area per molecule in mixtures was much lower than what would be expected from the individual components. Since then, the condensing effect and the ability of CHOL to induce ordering within the hydrocarbon chain of many lipid films, has been extensively characterized using Langmuir films [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29]. For instance, this technique has been used to bring new insight into the functional role of CHOL in milk polar lipids, used in the preparation of dairy emulsions, e.g., infant milk formulas. In particular, the role played by CHOL in the organization of biological membranes surrounding lipid droplets in milk, called the milk fat globule membrane (MFGM), has been recently investigated [30][31][32][33]. Accordingly, CHOL concentration facilitates the phase separation and reduces the mechanical resistance to rupture of coexisting phases in bilayer models of the MFGM. CHOL strongly affects the organization of the MFGM lipid monolayers by condensing the polar lipid molecules, decreasing the difference in height between domains on non-condensed phases and promoting the formation of numerous small domains in the condensed phase.In addition to the above mentioned studies of Langmuir Films, Atomic Force Microscopy (AFM) and Brewster Angle Microscopy (BAM) are complementary techniques that are vastly employed in the studies of lipid-CHOL interactions [13,24,25,28,34]. Although these techniques provide a direct correlation between the topography and force mapping, the exact mechanism of the interaction of CHOL with the indi...

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Atomic force microscopy as a tool to study the adsorption of DNA onto lipid interfaces

Cited by 7 publications

References 61 publications

DNA Interaction with a Polyelectrolyte Monolayer at Solution—Air Interface

DNA Interaction with a Polyelectrolyte Monolayer at Solution—Air Interface

Interactions of rod-like particles on responsive elastic sheets

Condensation of Model Lipid Films by Cholesterol: Specific Ion Effects

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