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Niga, P., Hansson-Mille, P., Swerin, A., Claesson, P. M., Schoelkopf, J., Gane, P., . . . Johnson, M. (2019). Propofol adsorption at the air/water interface: a combined vibrational sum frequency spectroscopy, nuclear magnetic resonance and neutron reflectometry study. Soft Matter, 15(1), 38-46
Open this publication in new window or tab >>Propofol adsorption at the air/water interface: a combined vibrational sum frequency spectroscopy, nuclear magnetic resonance and neutron reflectometry study
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2019 (English)In: Soft Matter, ISSN 1744-683X, E-ISSN 1744-6848, Vol. 15, no 1, p. 38-46Article in journal (Refereed) Published
Abstract [en]

Propofol is an amphiphilic small molecule that strongly influences the function of cell membranes, yet data regarding interfacial properties of propofol remain scarce. Here we consider propofol adsorption at the air/water interface as elucidated by means of vibrational sum frequency spectroscopy (VSFS), neutron reflectometry (NR), and surface tensiometry. VSFS data show that propofol adsorbed at the air/water interface interacts with water strongly in terms of hydrogen bonding and weakly in the proximity of the hydrocarbon parts of the molecule. In the concentration range studied there is almost no change in the orientation adopted at the interface. Data from NR show that propofol forms a dense monolayer with a thickness of 8.4 Å and a limiting area per molecule of 40 Å2, close to the value extracted from surface tensiometry. The possibility that islands or multilayers of propofol form at the air/water interface is therefore excluded as long as the solubility limit is not exceeded. Additionally, measurements of the 1H NMR chemical shifts demonstrate that propofol does not form dimers or multimers in bulk water up to the solubility limit.

Keywords
Cytology, Dimers, Hydrogen bonds, Interferometry, Molecules, Neutron reflection, Nuclear magnetic resonance, Nuclear magnetic resonance spectroscopy, Reflection, Reflectometers, Solubility, Air/Water Interfaces, Concentration ranges, Interfacial property, Neutron reflectometry, NMR chemical shifts, Solubility limits, Surface tensiometry, Vibrational sum-frequency spectroscopies, Phase interfaces
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-37020 (URN)10.1039/C8SM01677A (DOI)2-s2.0-85058894693 (Scopus ID)
Note

Funding details: U.S. Department of the Interior, TEST-2589; Funding details: Institute for Translational Neuroscience, ITN;

Available from: 2019-01-17 Created: 2019-01-17 Last updated: 2019-03-07Bibliographically approved
Niga, P., Hansson-Mille, P. M., Swerin, A., Claesson, P. M., Schoelkopf, J., Gane, P. A., . . . Johnson, C. M. (2018). Interactions between model cell membranes and the neuroactive drug propofol.. Journal of Colloid and Interface Science, 526, 230-243
Open this publication in new window or tab >>Interactions between model cell membranes and the neuroactive drug propofol.
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2018 (English)In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 526, p. 230-243Article in journal (Refereed) Published
Abstract [en]

phospholipid, NR data reveal that propofol is located exclusively in the head group region, which is rationalized in the context of previous studies. The results imply a non-homogeneous distribution of propofol in the plane of real cell membranes, which is an inference that requires urgent testing and may help to explain why such low concentration of the drug are required to induce general anaesthesia.

Keywords
Langmuir trough, Model membrane, Neutron reflectometry, Phospholipid monolayers, Propofol, Small amphiphilic drug, Surface pressure isotherm, Vibrational sum frequency spectroscopy
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-33920 (URN)10.1016/j.jcis.2018.03.052 (DOI)29734090 (PubMedID)2-s2.0-85046641029 (Scopus ID)
Available from: 2018-06-07 Created: 2018-06-07 Last updated: 2019-01-09Bibliographically approved
Oko, A., Claesson, P. M., Niga, P. & Swerin, A. (2016). Measurements and dimensional scaling of spontaneous imbibition of inkjet droplets on paper. Nordic Pulp & Paper Research Journal, 31(1), 156-169
Open this publication in new window or tab >>Measurements and dimensional scaling of spontaneous imbibition of inkjet droplets on paper
2016 (English)In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 31, no 1, p. 156-169Article in journal (Refereed) Published
Abstract [en]

We investigate theoretically and experimentally the spontaneous imbibition of water based inkjet formulations utilizing paper capillary rise and imbibition of inkjet drops. We approximate the paper structure to a two dimensional anisotropic porous material, and using Darcy's law as a base, we derive dimensionless groups that scale drop imbibition. This derivation is based on a previous dimensional scaling of drop imbibition on thick isotropic porous material. We apply this scaling to a paper substrate by measuring the average drop imbibition rate, and perform paper capillary rise experiments to obtain the average system parameters required for the scaling. The results suggest that this approach is a valuable tool to predict drop imbibition rates on paper. We then continue and perform the same sets of experiments on a different paper with similar structure that is surface treated (surface sized) with CaCl2 salt, an additive that is known to improve print quality. We find that due to rapid aggregation of the colorant ink by the CaCl2, the imbibition rate is slowed down in the capillary rise experiments, i.e., on much larger scales compared to a single inkjet drop. However, the presence of CaCl2 has only minor effect over the average imbibition rates of single drops. Imbibition rates on the CaCl2 surface sized paper did not give adequate scaling as a result of the fact that the aggregation was not included the theoretical assumptions behind the scaling.

Place, publisher, year, edition, pages
SPCI, 2016
Keywords
aggregation, Darcy flow, dimensional scaling, divalent cations, imbibition, infiltration, ink, inkjet, paper, porous material
National Category
Paper, Pulp and Fiber Technology Manufacturing, Surface and Joining Technology
Identifiers
urn:nbn:se:ri:diva-94 (URN)10.3183/npprj-2016-31-01-p156-169 (DOI)2-s2.0-84961674015 (Scopus ID)
Available from: 2016-05-31 Created: 2016-04-28 Last updated: 2019-06-17Bibliographically approved
Niga, P., Örtegren, J., Alecrim, V., Klaman, M., Blohm, E. & Lofthus, J. (2012). Hybrid printing: paper media for combined flexographic and inkjet printing (ed.). In: : . Paper presented at International paper physics conference, Stockholm, June 10-14, 2012, pp 79-81.
Open this publication in new window or tab >>Hybrid printing: paper media for combined flexographic and inkjet printing
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2012 (English)Conference paper, Published paper (Refereed)
Publisher
p. 3
National Category
Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:ri:diva-9498 (URN)
Conference
International paper physics conference, Stockholm, June 10-14, 2012, pp 79-81
Available from: 2016-09-12 Created: 2016-09-12 Last updated: 2018-08-13Bibliographically approved
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-0195-3850

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