Coalescence of oil droplets and collection of vesicles by optical pressure

Yumeki Tani, Takashi Kaneta

Research output: Contribution to journalArticlepeer-review


We demonstrated the utility of optical pressure in the manipulation of oil droplets and vesicles in the field of analytical chemistry. In order to realize chemical analysis in a limited small space, a method to capture and coalesce two oil droplets was developed using two laser beams. Three types of stabilizers for the formation of oil droplets were explored to achieve the coalescence of two droplets whereas polyethylene glycol (PEG) was the most suitable one among them. When using the oil droplets with PEG, the increase in temperature of the medium induced successful coalescence of two droplets. We also developed a method to collect liposomes, which are a model of artificial extracellular vesicles, using optical pressure. It was found that the collection efficiency was significantly improved by adding gold nanoparticles into the solution. This effect is due to thermal convection induced by the optical absorption of gold nanoparticles in solution and an enhancement of the optical pressure caused by binding between the vesicles and the gold nanoparticles. It was also elucidated that the binding was strongly related to the electrostatic interaction in addition to the hydrophobic interaction. Based on these findings, we achieved the collection of nanometer-sized vesicles and exosomes released by cells by optical pressure.

Original languageEnglish
Pages (from-to)665-672
Number of pages8
Issue number12
Publication statusPublished - 2020


  • Exosome
  • Gold nanoparticle
  • Liposome
  • Oil droplet
  • Optical pressure

ASJC Scopus subject areas

  • Analytical Chemistry


Dive into the research topics of 'Coalescence of oil droplets and collection of vesicles by optical pressure'. Together they form a unique fingerprint.

Cite this