Influence of Poly(ethylenimine) on the Monolayer of Oleic Acid at the Air/Water Interface

Ha, Tai Hwan; Kim, Dai Kyu; Choi, Myung-Un; Kim, Kwan

doi:10.1006/jcis.2000.6819

Cited by 8 publications

(5 citation statements)

References 25 publications

(21 reference statements)

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“…Under the applied conditions (pH 2.0 and a relatively high temperature), the film of OA at 10 mN/m has the features of the Z-type film, which means that the molecules can be transferred only in upstroke. Our results are in agreement with an earlier study . This type of transfer is characteristic for rigid monolayers, and in this case, it may be an evidence of too loose monolayer.…”

Section: Resultssupporting

confidence: 93%

“…Consequently, a smaller molecular area was occupied by the OA monolayer spread on water than on the acidic subphase. Our results are in agreement with the study on OA monolayers spread on poly(ethylenimine) (PEI) solution at different pH values, which confirmed that the pKa of OA is considerably lower at the air/water interface than in the bulk phase …”

Section: Resultssupporting

confidence: 92%

“…It seems that the acidic pH used in our study caused the formation of a thinner OA film. Moreover, earlier studies confirmed that OA molecules can exist in a monomeric state in an X-type LB film assembled at acidic pH . Contrary to the stable OA monolayer deposited at 10 mN/m (Figure a), each part of the fragmented OA monolayer (Figure b) could be removed or moved to different locations very easilyalso in the intermittent contact mode (see the vertical lines in Figure b as the recorded paths of the monolayer parts moved by the atomic force microscope tip from the bottom to the top of the picture).…”

Section: Resultsmentioning

confidence: 70%

“…The impact of BLA III on the OA monolayer is more complex than that in the case of previously described PEI . However, the interactions between the components are similarly pH-dependent.…”

Section: Resultsmentioning

confidence: 71%

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Temperature, pH, and Molecular Packing Effects on the Penetration of Oleic Acid Monolayer by α-Lactalbumin

et al. 2019

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Recently, we reported on the interfacial behavior of mixed oleic acid (OA)-α-lactalbumin monolayer and its relevance in the formation of tumoricidal HAMLET (human α-lactalbumin made lethal to tumor cells)-like complex. This complex is probably formed in the gastrointestinal tract, but it has not been proved so far. The molecular base and the underlying physicochemical forces leading to such complexation remain to be known as well. There are also several other issues related with the complex stoichiometry that need to be fully explained. This study provides insight into the mechanism of temperature, pH, and physical state of monolayer-dependent binding of OA by the milk proteinapo-α-lactalbumin. Using the Langmuir and Langmuir–Blodgett approaches, we investigated the interactions between the OA monolayer and the apo-bovine α-lactalbumin (BLA III) at different pH, temperatures, and molecular packing. We found that the most favorable conditions for the formation of mixed OA–BLA III film are relevant to the gastric environment. The stabilization of OA–BLA III at the interface is associated with the conformational changes of protein in the presence of fatty acids induced by low pH and high temperature in the expanded monolayer. Our approach helps to understand the molecular mechanism of HAMLET/bovine α-lactalbumin made lethal to tumor cells formation in vivo.

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Section: Resultssupporting

confidence: 93%

Section: Resultssupporting

confidence: 92%

Section: Resultsmentioning

confidence: 70%

“…The impact of BLA III on the OA monolayer is more complex than that in the case of previously described PEI . However, the interactions between the components are similarly pH-dependent.…”

Section: Resultsmentioning

confidence: 71%

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Temperature, pH, and Molecular Packing Effects on the Penetration of Oleic Acid Monolayer by α-Lactalbumin

et al. 2019

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“…A second suspension was prepared by adding a precise amount of oleic acid molecules to reach 52% in weight of the solid. According to the size of the NPs and the mean molecular area occupied by a single oleic acid molecule (about 0.42 nm 2 /molecule) − and considering a monolayer of surfactants, about 65% and 225% of the NP surface would be covered by oleic acid molecules when using the initial and the second suspensions, respectively. However, oleic acid molecules are characterized by an equilibrium between grafted molecules at the surface of nanoparticles and free molecules in the solvent.…”

Section: Resultsmentioning

confidence: 99%

2D Assembling of Magnetic Iron Oxide Nanoparticles Promoted by SAMs Used as Well-Addressed Surfaces

et al. 2010

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Well-addressed surfaces which consist of self-assembled monolayers (SAMs) of organic molecules have been used to control the assembling of magnetic iron oxide nanoparticles (NPs) coated with oleic acid molecules. The assembling occurs through interactions between the surface of NPs and specific functional terminal groups at the interface of the SAMs and the NP suspension. Polar head groups such as carboxylic acid and hydroxyl promote the assembling of NPs whereas nonpolar groups such as methylene avoid the assembling onto SAMs. The kinetics of the NP assembling is highly dependent on the polarity of terminal groups of the SAMs. Carboxylic acid groups have been shown to promote faster formation of a dense monolayer of NPs than hydroxyl groups. In addition, oleic acid used as a coating agent enables the high stability of the NP suspension and its concentration influences dramatically the kinetics of the assembling. The mechanism proceeds by a ligand exchange process between surfactant on the NP surface and terminal groups at the interface of the SAM with the suspension.

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Dip‐Pen Nanolithography of Chemical Templates on Silicon Oxide

et al. 2004

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A. Hagfeldt, M. Grätzel, Chem. Rev. 1995, 95, 49. [17] The intensity was determined by comparing the measured J SC with the J SC at 1 sun intensity, which was obtained from the convolution of the spectral response with the solar AM1.5 spectrum, and correcting for the small nonlinearity of the light intensity dependence using I = I(1 sun) [J SC /J SC (1 sun)] The range of material systems to which DPN and related techniques have been applied has rapidly expanded since the first report of depositing thiols on gold surfaces, [2±4] to include patterning of proteins [5] and DNA [6] on gold surfaces, and metal salts, [7,8] metal oxides, [9] silazanes, [10,11] alkoxysilanes, [11,12] organic dyes, [13] dendrimers, [14] and polymers [15] on silicon oxide surfaces. Herein we describe a new functional ink based on trichlorosilane chemistry that is amenable to deposition by DPN onto silicon oxide. Additionally, we show this produces a versatile template that can direct subsequent deposition or growth of a variety of materials. Lithography on insulating substrates at ever-shrinking scales is critical to the future development of electronic and sensor devices. DPN has been shown to provide a facile method for the serial patterning of silicon oxide surfaces. Ivanisevic and Mirkin [10] described the deposition of hexamethyldisilazane (HMDS) on Si and GaAs native oxide surfaces using DPN; however, HMDS is not amenable to further chemical functionalization after patterning. In order to pattern molecules on silicon oxide with DPN, Mirkin and co-workers have also created etch-resists based on self-assembled monolayers. [16,17] In this approach, a thin sacrificial layer of gold is deposited on a silicon oxide substrate, followed by patterning of a thiol on the gold by DPN. A final chemical etching step removes the unpatterned gold areas. More recent papers by Pena et al. [11] and Jung et al. [12] have explored the ability of In our studies, we have chosen 10-undecenyltrichlorosilane (UTCS) as the DPN ink' for several reasons. The choice of UTCS, or trichlorosilanes in general, allows the direct patterning of molecules on silicon oxide without the need for a solvent or elevated temperatures. Our approach results in the direct covalent attachment through only the headgroup of the silane, leaving the olefin-terminated tail (in the case of UTCS) available as a flexible starting point for further chemical modification. Possible modifications include the covalent or noncovalent growth of nanoparticles, conducting polymers, metal films, or biomolecules.Although some authors have proposed that trichlorosilanes and alkoxysilanes would be unsuitable inks' for DPN [10] (due to possible decomposition or polymerization in the water meniscus that forms between the tip and surface), Pena et al. [11] and Jung et al. [12] have both found that deposition is possible in the case of alkoxysilanes. Given careful tip preparation, we have found that trichlorosilanes can also be written under appropriate conditions. Specifically, to ach...

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Influence of Poly(ethylenimine) on the Monolayer of Oleic Acid at the Air/Water Interface

Cited by 8 publications

References 25 publications

Temperature, pH, and Molecular Packing Effects on the Penetration of Oleic Acid Monolayer by α-Lactalbumin

Temperature, pH, and Molecular Packing Effects on the Penetration of Oleic Acid Monolayer by α-Lactalbumin

2D Assembling of Magnetic Iron Oxide Nanoparticles Promoted by SAMs Used as Well-Addressed Surfaces

Dip‐Pen Nanolithography of Chemical Templates on Silicon Oxide

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