Specific adsorption of bitter substances on lipid bilayer-coated piezoelectric crystals

Okahata, Yoshio; Ebato, Hiroshi; Taguchi, Kazuhiro

doi:10.1039/c39870001363

Cited by 47 publications

(15 citation statements)

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“…Local anaesthetics are secondary or tertiary amines with pK, values that lie between 8 and 9; in physiological solutions, therefore, they exist both as neutral and as cationic forms. Partition coefficients oftetracaine in the 2CI8N+2Cl/PSS-films were obtained at various ambient pH values (3)(4)(5)(6)(7)(8)(9)(10)(11)(12) and the results are shown in Fig. 8.…”

Section: Resultsmentioning

confidence: 99%

Adsorption behaviour of local anaesthetics in synthetic lipid membranes coated on a quartz-crystal microbalance and correlations with their anaesthetic potencies

Okahata¹,

Ebato²

1991

J. Chem. Soc., Perkin Trans. 2

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The partition coefficients in a lipid matrix of seven local anaesthetics in clinical use were obtained using quartz-crystal microbalance (QCM) coated with a synthetic lipid multibilayer film; the resonance frequency of the QCM changes linearly with the amount adsorbed by the lipid matrix. A good correlation was observed between the partition coefficients so determined and the intrinsic local anaesthetic potencies of the same compounds obtained from biological experiments: anaesthetics that induce strong local anaesthesia showed greatest partition into the lipid matrix. The partition coefficients depended on the phase transition of the lipid matrix on the QCM and the ambient p H in the aqueous phase. The uncharged form of amino-type local anaesthetics is strongly adsorbed by the lipid membrane and penetrates deeply into the lipid matrix, especially in the fluid liquid-crystalline state above the phase-transition temperature ( T J , compared with the cationic anaesthetic species present in acidic aqueous solutions.

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Section: Resultsmentioning

confidence: 99%

Adsorption behaviour of local anaesthetics in synthetic lipid membranes coated on a quartz-crystal microbalance and correlations with their anaesthetic potencies

Okahata¹,

Ebato²

1991

J. Chem. Soc., Perkin Trans. 2

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“…In this study, as an extension of our series of studies on photochemically driven dithiocarbamate-based surface macromolecular microarchitectural design, − , we studied the in situ polymerization behaviors of various monomers, using the quartz crystal microbalance (QCM) technique, − in which polymer chains produced by graft copolymerization on the gold electrodes of QCM could be weighed in real time in nanogram order.…”

Section: Introductionmentioning

confidence: 99%

In Situ Observation of Dithiocarbamate-Based Surface Photograft Copolymerization Using Quartz Crystal Microbalance

Nakayama

Matsuda

1999

Macromolecules

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A quartz crystal microbalance (QCM) technique which can detect weight increase in the nanogram order has been employed to continuously monitor the iniferter-based surface photograft polymerization behavior of vinyl monomers. The gold electrodes of the QCM were thinly coated with a photoreactive polystyrene partially derivatized with N,N-diethyldithiocarbamylmethyl groups acting as iniferters. A monotonic decrease in the resonance frequency of the vibrating oscillator of QCM, which was correlated with the weight increase via graft copolymerization initiated on the polystyrene, occurred immediately after ultraviolet light irradiation of the coated electrode surface in a methanolic or aqueous solution of vinyl monomers such as acrylamide (AAm), N,N-dimethylacrylamide (DMAAm), methacrylamide (MAm), methacrylic acid (MA), ethyl acrylate (EA), 2-hydroxyethyl methacrylate (HEMA), 2-(dimethylamino)ethyl methacrylate (DMAEM), N-vinyl-2-pyrrolidone (VP), and styrene (ST), except for vinyl acetate (VA). Upon cessation of irradiation, little frequency change was observed. The cycle comprising a decrease in resonance frequency under irradiation and no change under dark condition was repeated without appreciable fatigue. The polymer yield showed an almost linear increase with irradiation time up to 20 min. The apparent polymerization rate increased with concentration of monomer, light intensity, and surface density of dithiocarbamate groups. In addition, the rate was dependent on monomer's Q value and maximum at Q values of around 0.7−0.8 for EMA and HEMA.

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“…Increasing pH also decreased the frequency: e.g., the decreases at pH 12.0 were 100 and 150 Hz at 25 and 30°C for TP, 100 and 120 Hz at 25 and 30°C for TM, and 100 and 200 Hz at 25 and 30°C for CA, respectively. These decreases correspond to increases in the weight by about OfY0.95 ng for 2 ~ng of the lipids [4]. To confirm that such a variation is not caused by some hydrophilic fatty acid impurities in the triglycerides, we performed the same experiment with analytical grade TP.…”

Section: Resultsmentioning

confidence: 90%

Lipid Detergency as Observed by the Quartz Microbalance Method

Shimomura

Onozawa

Komiyama

et al. 2003

Textile Research Journal

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Removing solid lipids with surfactants in an aqueous solution is observed with a quartz crystal microbalance. The pH of the bathing solution is adjusted to 7.0-12.0 at 25 and 30°C. Concentrations of four anionic and nonionic surfactants vary from far below the CMC to ten times the CMC. The alkalinity of the solution at pH 9.0-12.0 causes swelling of the lipids by about 10%, but adding surfactants results in swelling up to 10-20%, followed by lipid removal by solubilization. This removal takes place at concentrations lower than the CMC. From this fact and the dependence on surfactant concentration of the removal rates by the two kinds of surfactants, we can infer that micelles of anionic surfactants do not participate in the removal, while those of nonionic surfactants do participate.Removing various lipids from textiles is an important process in scouring and cleaning. This process is complex, comprising mechanical abrasion, rolling up, and chemical solubilization of liquefied lipids. Among these mechanisms, the last one is crucial for scouring to control lipid content in textiles. It is also important for the performance of heavy duty detergents in daily use. Some studies have been devoted to the real time observation of the removal process of solid lipids: liquefaction or the swelling of the lipids by water and surfactant, and subsequent removal, have been observed by radiotagging, gravimetric, FTIR spectroscopic, ellipsometric, and quartz crystal microbalance (QCM) methods [ 1, 2, 3, 5, 7].These observations are confined to specific conditions for a particular lipid, surfactant, and concentration, etc. It is informative to study the process from a comparative view point with regard to lipid and surfactant species, surfactant concentration, degree of swelling of lipids, and removal rate.In a series of studies on soil removal, we reported a real time observation of some solid proteins by protease [6]. We used the QCM technique for these observations by monitoring the weight increase and accompanying decrease of protein coated on the gold electrode of a QCM as the frequency change around 9 MHz. In this study, we report the removal process of tripalmitin (TP), trimyristin (TM), and cetyl alcohol (CA) from the surface of the electrode of the QCM by anionic surfac-~i tanits-sodium dodecylbenzc~nesulfonate (DBS) and sodium dodecyl sulfate (SDS)---and nonionic surfactantsdodecyl heptaethyleneoxide (C,2(EO)~) and hexadecyl I heptaethyleneoxide (C 16(EOh)-in an aqueous medium of pH 7.0-12.0 at 25 and 30'C. In this paper, we discuss the swelling behaviors of the lipids and variations in the removal rates to interpret the process. j Experimental Reagent grade TP, TM, and CA were supplied by Tokyo Kasei Kogyo Co.. Ltd.. and used as received.Analytical grade TP from the same company was used to test the effect of impurities. The melting points of TP, TM, and CA are 66, 56-57, and 49°C, respectivety. DBS, supplied as sodium n-dodecylbenzensulfonate by Wako Pure Chemical Industries, and SDS, supplied by Nakarai Tasque, In...

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Specific adsorption of bitter substances on lipid bilayer-coated piezoelectric crystals

Cited by 47 publications

References 1 publication

Adsorption behaviour of local anaesthetics in synthetic lipid membranes coated on a quartz-crystal microbalance and correlations with their anaesthetic potencies

Adsorption behaviour of local anaesthetics in synthetic lipid membranes coated on a quartz-crystal microbalance and correlations with their anaesthetic potencies

In Situ Observation of Dithiocarbamate-Based Surface Photograft Copolymerization Using Quartz Crystal Microbalance

Lipid Detergency as Observed by the Quartz Microbalance Method

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