title: Fluorescence Recovery after Merging a Droplet to Measure the Two-dimensional Diffusion of a Phospholipid Monolayer.
abstract: We introduce a new method to measure the lateral diffusivity of a surfactant monolayer at the fluid-fluid interface, called fluorescence recovery after merging (FRAM). FRAM adopts the same principles as the fluorescence recovery after photobleaching (FRAP) technique, especially for measuring fluorescence recovery after bleaching a specific area, but FRAM uses a drop coalescence instead of photobleaching dye molecules to induce a chemical potential gradient of dye molecules. Our technique has several advantages over FRAP: it only requires a fluorescence microscope rather than a confocal microscope equipped with high power lasers; it is essentially free from the selection of fluorescence dyes; and it has far more freedom to define the measured diffusion area. Furthermore, FRAM potentially provides a route for studying the mixing or inter-diffusion of two different surfactants, when the monolayers at a surface of droplet and at a flat air/water interface are prepared with different species, independently.
authors.affiliation: Department of Bio and Brain Engineering, KAIST.
authors.forename: Dae-Woong
authors.initials: DW
authors.lastname: Jeong
authors.affiliation: Information and Electrical Research Institute, KAIST.
authors.forename: KyuHan
authors.initials: K
authors.lastname: Kim
authors.affiliation: Department of Bio and Brain Engineering, KAIST.
authors.forename: Myung Chul
authors.initials: MC
authors.lastname: Choi
authors.affiliation: Information and Electrical Research Institute, KAIST; sqchoi@kaist.ac.kr.
authors.forename: Siyoung Q
authors.initials: SQ
authors.lastname: Choi
mesh_terms: D004058:Diffusion; D036681:Fluorescence Recovery After Photobleaching / Q000379:methods*; D008856:Microscopy, Fluorescence; D010743:Phospholipids / Q000737:chemistry*; D038761:Photobleaching; D013501:Surface-Active Agents / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: D010743:Phospholipids; D013501:Surface-Active Agents; D014867:Water