Phospholipase A2 activity on supported thiolipid monolayers monitored by electrochemical and SPR methods

Jabłonowska, Elżbieta; Więckowska, Agnieszka; Rogalska, Ewa; Bilewicz, Renata

doi:10.1016/j.jelechem.2011.03.018

Cited by 9 publications

(8 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This value has been obtained as the mean value of three different measurements performed on three different electrodes. This value is, within the experimental error, in very good agreement with that obtained by QCM measurements, and with one reported in literature . However, this is not in accordance with a further value previously reported related to an incubation performed in methanol solution (Table ).…”

Section: Resultssupporting

confidence: 87%

“…This value is, within the experimental error, in very good agreement with that obtained by QCM measurements, and with one reported in literature. 33 However, this is not in accordance with a further value previously reported 30 related to an incubation performed in methanol solution (Table 1). The reduction peak is located at 0.97 V and the full width at half of the peak maximum height is 0.101 ± 0.010, suggesting some inhomogeneity in the monolayer.…”

Section: ■ Experimental Sectioncontrasting

confidence: 81%

“…The average surface density value obtained with QCM experiments is 2.6 times lower than the value recently reported in literature, that is, equal to 4.52 × 10 −10 mol/cm 2 (Table 1), 30 but it is similar to the value reported by Jablonowska and coworkers (2.2 × 10 −10 mol/cm 2 , Table 1). 33 However, CV experiments performed in an aqueous K 3 [Fe(CN) 6 ] solution on the gold-covered quartz electrode after the deposition showed that 80% of the electrode area was covered by the DPPTE SAM (Figure S4, Supporting Information), suggesting that the real surface coverage obtained with atomically flat electrodes after 18 h incubation is 2.3 ± 0.2 × 10 −10 mol/cm 2 .…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

“…This confers to the film great stability, because of the Au–S bond (45 kJ/mol) and the close packing of the underlying alkanethiol SAM layer: on the other hand, the environment is less fluid than a normal phospholipid bilayer leaflet. To avoid this problem, the use of a commercially available diacyl phospholipid, functionalized with a thiol group, 1,2-dipalmitoyl- sn -glycero-3-phosphothioethanol (DPPTE, Figure ), has been recently introduced, either as a molecular monolayer − or as the first layer of a hybrid bilayer. − In this molecule, the thiol group is located on the phospholipid polar head, letting the hydrophobic chain protrude from the film (Figure ). For this reason, the DPPTE monolayer on the surface should look like a hydrophobic SAM of alkanethiol. ,− This system, despite being widely investigated in the literature, produced very variable experimental results, strongly depending on the experimental conditions used for the film formation.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

DPPTE Thiolipid Self-Assembled Monolayer: A Critical Assay

et al. 2016

View full text Add to dashboard Cite

Supported lipid membranes represent an elegant way to design a fluid interface able to mimic the physicochemical properties of biological membranes, with potential biotechnological applications. In this work, a diacyl phospholipid, the 1,2-dipalmitoyl-sn-glycero-3-phosphothioethanol (DPPTE), functionalized with a thiol group, was immobilized on a gold surface. In this molecule, the thiol group, responsible for the Au-S bond (45 kJ/mol) is located on the phospholipid polar head, letting the hydrophobic chain protrude from the film. This system is widely used in the literature but is no less challenging, since its characterization is not complete, as several discordant data have been obtained. In this work, the film was characterized by cyclic voltammetry blocking experiments, to verify the SAM formation, and by reductive desorption measurements, to estimate the molecular density of DPPTE on the gold surface. This value has been compared to that obtained by quartz crystal microbalance measurements. Ellipsometry and impedance spectroscopy measurements have been performed to obtain information about the monolayer thickness and capacitance. The film morphology was investigated by atomic force microscopy. Finally, Monte Carlo simulations were carried out, in order to gain molecular information about the morphologies of the DPPTE SAM and compare them to the experimental results. We demonstrate that DPPTE molecules, incubated 18 h below the phase transition temperature (T = 41.1 ± 0.4 °C) in ethanol solution, are able to form a self-assembled monolayer on the gold surface, with domain structures of different order, which have never been reported before. Our results make possible rationalization of the scattered results so far obtained on this system, giving a new insight into the formation of phospholipids SAMs on a gold surface.

show abstract

Section: Resultssupporting

confidence: 87%

Section: ■ Experimental Sectioncontrasting

confidence: 81%

Section: ■ Experimental Sectionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

DPPTE Thiolipid Self-Assembled Monolayer: A Critical Assay

et al. 2016

View full text Add to dashboard Cite

show abstract

“…1). This thiolipid has been used so far either as a tethering layer in tBLM systems employed, e.g., for studying ion-channel proteins on electrode surfaces or as a model membrane in the studies of a lipolytic enzyme, phospholipase A2, which was employed as a tool for modifying the structure of supported thiolipid layers in a controlled way [21–22]. Due to the presence of a thiol group in the polar headgroup region, this lipid has negative charge and it is possible to transfer monolayers onto solid support by means of both Langmuir–Blodgett method and self-assembly, which results in the differences in the packing of the thiolipid molecules in the supported layers depending on the mode of transfer [23].…”

Section: Introductionmentioning

confidence: 99%

Comparison of the interactions of daunorubicin in a free form and attached to single-walled carbon nanotubes with model lipid membranes

Matyszewska¹

2016

Beilstein J. Nanotechnol.

View full text Add to dashboard Cite

SummaryIn this work the interactions of an anticancer drug daunorubicin (DNR) with model thiolipid layers composed of 1,2-dipalmitoyl-sn-glycero-3-phosphothioethanol (DPPTE) were investigated using Langmuir technique. The results obtained for a free drug were compared with the results recorded for DNR attached to SWCNTs as potential drug carrier. Langmuir studies of mixed DPPTE–SWCNTs-DNR monolayers showed that even at the highest investigated content of the nanotubes in the monolayer, the changes in the properties of DPPTE model membranes were not as significant as in case of the incorporation of a free drug, which resulted in a significant increase in the area per molecule and fluidization of the thiolipid layer. The presence of SWCNTs-DNR in the DPPTE monolayer at the air–water interface did not change the organization of the lipid molecules to such extent as the free drug, which may be explained by different types of interactions playing crucial role in these two types of systems. In the case of the interactions of free DNR the electrostatic attraction between positively charged drug and negatively charged DPPTE monolayer play the most important role, while in the case of SWCNTs-DNR adducts the hydrophobic interactions between nanotubes and acyl chains of the lipid seem to be prevailing. Electrochemical studies performed for supported model membranes containing the drug delivered in the two investigated forms revealed that the surface concentration of the drug-nanotube adduct in supported monolayers is comparable to the reported surface concentration of the free DNR incorporated into DPPTE monolayers on gold electrodes. Therefore, it may be concluded that the application of carbon nanotubes as potential DNR carrier allows for the incorporation of comparable amount of the drug into model membranes with simultaneous decrease in the negative changes in the membrane structure and organization, which is an important aspect in terms of side effects of the drug.

show abstract

Optical fiber bio-sensor for phospholipase using liquid crystal

Tang

Xie

et al. 2020

Biosensors and Bioelectronics

View full text Add to dashboard Cite

Phospholipase A2 activity on supported thiolipid monolayers monitored by electrochemical and SPR methods

Cited by 9 publications

References 31 publications

DPPTE Thiolipid Self-Assembled Monolayer: A Critical Assay

DPPTE Thiolipid Self-Assembled Monolayer: A Critical Assay

Comparison of the interactions of daunorubicin in a free form and attached to single-walled carbon nanotubes with model lipid membranes

Optical fiber bio-sensor for phospholipase using liquid crystal

Contact Info

Product

Resources

About