Self-Propelled Oil Droplets and Their Morphological Change to Giant Vesicles Induced by a Surfactant Solution at Low pH

Collective motion is ubiquitous in living systems. Although various biomimetic artificial systems have been constructed, there have been few studies reported on collective motion induced by the coupling of chemical reactions, diffusion and convection in a far-from-equilibrium state. In this study, we report an artificial system of oil droplets in a surfactant solution wherein the collective motion of multiple droplets and pattern formation occurred concurrently. Using photo-responsive surfactants with an azobenzene moiety, the assembly of droplets and the formation of circular patterns around the formed droplet clusters occurred under UV illumination, whereas the disassembly of droplets and disappearance of the patterns occurred under subsequent visible light illumination. The observed dynamics were induced by Marangoni flows based on the reversible photoisomerisation of azobenzene-containing surfactants. The phenomena were considered analogous to the bioconvection of microorganisms. These findings could be useful for understanding the mechanism of motion of life in terms of physicochemical aspects.<br>

Download Full-text

S056021 Light Scattering in a Shear Flow of Surfactant Solution Including Micro Oil Droplets

The Proceedings of Mechanical Engineering Congress Japan ◽

10.1299/jsmemecj.2011._s056021-1 ◽

2011 ◽

Vol 2011 (0) ◽

pp. _S056021-1-_S056021-2

Author(s):

Takashi KOSHIBA ◽

Takehiro YAMAMOTO

Keyword(s):

Light Scattering ◽

Shear Flow ◽

Surfactant Solution ◽

Oil Droplets

Download Full-text

Kinetics of lactate transport in sarcolemmal giant vesicles obtained from human skeletal muscle

Journal of Applied Physiology ◽

10.1152/jappl.1994.76.3.1031 ◽

1994 ◽

Vol 76 (3) ◽

pp. 1031-1036 ◽

Cited By ~ 27

Author(s):

C. Juel ◽

S. Kristiansen ◽

H. Pilegaard ◽

J. Wojtaszewski ◽

E. A. Richter

Keyword(s):

Lactate Concentration ◽

Low Ph ◽

Marker Enzyme ◽

Lactate Transport ◽

Giant Vesicles ◽

Biopsy Material ◽

Muscle Lactate ◽

Transport Studies ◽

Equilibrium Exchange ◽

Vesicular Membrane

We developed a method that allows the measurement of muscle lactate transport in humans. The transport studies were carried out with giant (1.8- to 36-microns-diam) sarcolemmal vesicles obtained by collagenase treatment of needle biopsy material. Marker enzyme analyses demonstrated that the vesicular membrane is predominantly of sarcolemmal origin, contamination with sarcoplasmic reticulum membranes is very low, and mitochondrial membranes are not a major contaminant. The vesicles were loaded with labeled lactate, and the efflux was measured. The system displayed saturation kinetics and inhibitor sensitivity. In equilibrium exchange experiments (pH 7.4, 21 degrees C), the Michaelis-Menten constant (Km) for the carrier-mediated flux was 30 +/- 8 (SD) mM and maximal transport rate (Vmax) was 184 +/- 24 pmol.cm-2.s-1 (142 nmol.mg protein-1.min-1). In zero-trans efflux experiments, Km was 24 +/- 8 mM and Vmax was 81 +/- 11 pmol.cm-2.s-1 (63 nmol.mg protein-1.min-1). In infinite-cis experiments with a variable lactate concentration on the outside of the vesicles, Km was 8 +/- 4 mM and Vmax was 136 +/- 9 pmol.cm-2.s-1 (105 nmol.mg protein-1.min-1). Thus, the system displayed transacceleration. Low pH (6.4) had no significant effect on equilibrium exchange experiments, whereas in zero-trans experiments low pH at the trans side inhibited the flux by 50%. We concluded that lactate transport can be studied in giant vesicles obtained from a single human muscle biopsy. Our data provide evidence for the existence of a lactate carrier in human sarcolemma. This transport system must be taken into account in models of human lactate kinetics.

Download Full-text

Phototactic behavior of self-propelled micrometer-sized oil droplets in a surfactant solution

Chemical Communications ◽

10.1039/c6cc09236e ◽

2017 ◽

Vol 53 (14) ◽

pp. 2237-2240 ◽

Cited By ~ 14

Author(s):

Sho Kaneko ◽

Kouichi Asakura ◽

Taisuke Banno

Keyword(s):

Equilibrium State ◽

Surfactant Solution ◽

Oil Droplets ◽

Phototactic Behavior ◽

Far From Equilibrium

We demonstrate the phototactic behavior of self-propelled micrometer-sized oil droplets in a far-from-equilibrium state.

Download Full-text

Effect of interaction between anionic surfactants and poly(piperazine-amide) nanofiltration membranes used for chromium(III) recovery from saline solution

Water Science & Technology ◽

10.2166/wst.2015.406 ◽

2015 ◽

Vol 72 (10) ◽

pp. 1803-1809 ◽

Cited By ~ 3

Author(s):

P. Religa ◽

A. Kowalik-Klimczak

Keyword(s):

Surface Layer ◽

Permeability Coefficient ◽

Saline Solution ◽

Membrane Surface ◽

Sodium Dodecyl ◽

Substantial Reduction ◽

Surfactant Solution ◽

Low Ph ◽

Chemical Cleaning ◽

Long Period

The effect of the anionic surfactant on the permeation properties of the nanofiltration (NF) membranes used for chromium(III) recovery from saline solution at low pH have been presented in this paper. The membrane surface layer performance periodically modified by sodium dodecyl sulphate (SDS) solution has been studied with measurements of zeta potential, atomic force microscopy (AFM) and permeability coefficient of tested membranes. It was found that the membrane surface layer modification by SDS caused a substantial reduction in the possibility of separation of loose NF membrane characterized by a high density of positively charged groups activating under the effect of the low pH of the saline solutions (HL membrane). On the other hand, in the case of dense NF membranes characterized by a strong negatively charged surface (DL membrane) constituting used the SDS improves the separation of chloride and chromium(III) ions. In this case, the surfactant solution also provides a high membrane permeability coefficient behavior over a long period of use. DL membrane modification by SDS allowed both to retain the stable membrane working for a long period and to limit the frequency of the chemical cleaning of this membrane.

Download Full-text

Transformation of oil droplets into giant vesicles

Chemical Communications ◽

10.1039/c6cc01867j ◽

2016 ◽

Vol 52 (50) ◽

pp. 7786-7789 ◽

Cited By ~ 5

Author(s):

Li Sheng ◽

Kensuke Kurihara

Keyword(s):

Giant Vesicles ◽

Oil Droplets ◽

Oil Droplet ◽

New Process

We propose a protocell model in which compartments are constructed via a new process involving the formation of robust vesicles using an autocatalytic, self-reproducing oil droplet system as a ‘scaffold’.

Download Full-text

Photoinduced Collective Motion of Oil Droplets and Concurrent Pattern Formation in Surfactant Solution

10.33774/chemrxiv-2021-w8lml-v2 ◽

2021 ◽

Author(s):

Tomoya Kojima ◽

Hiroyuki Kitahata ◽

Kouichi Asakura ◽

Taisuke Banno

Keyword(s):

Pattern Formation ◽

Collective Motion ◽

Surfactant Solution ◽

Light Illumination ◽

Artificial System ◽

Oil Droplets ◽

Uv Illumination ◽

Azobenzene Moiety ◽

Visible Light Illumination ◽

Far From Equilibrium

Collective motion is ubiquitous in living systems. Although various biomimetic artificial systems have been constructed, there have been few studies reported on collective motion induced by the coupling of chemical reactions, diffusion and convection in a far-from-equilibrium state. In this study, we report an artificial system of oil droplets in a surfactant solution wherein the collective motion of multiple droplets and pattern formation occurred concurrently. Using photo-responsive surfactants with an azobenzene moiety, the assembly of droplets and the formation of circular patterns around the formed droplet clusters occurred under UV illumination, whereas the disassembly of droplets and disappearance of the patterns occurred under subsequent visible light illumination. The observed dynamics were induced by Marangoni flows based on the reversible photoisomerisation of azobenzene-containing surfactants. The phenomena were considered analogous to the bioconvection of microorganisms. These findings could be useful for understanding the mechanism of motion of life in terms of physicochemical aspects.

Download Full-text