title: Elevation of plasma membrane permeability on laser irradiation of extracellular latex particles.
abstract: In this report, we describe a laser-latex combination system that enables membrane-impermeable molecules to penetrate cell membranes. Laser light (Q-switched Nd:YAG laser, 532.5 nm) was used to irradiate a mixture of commercial latex particles (blue dyed, 1 micro m in diameter) and mouse fibrosarcoma (Meth-A) cells. After irradiation, membrane permeability was evaluated by flow cytometric assaying using propidium iodide (PI) and fluorescein diacetate (FDA). The proportion of permeabilized-resealed cells was affected by changes in the light intensity (approximately 780 mW/cm(2)), the irradiation time (approximately 240 s), and/or the particle concentration (approximately 10(9) particles/ml). The permeability persisted up to 20 min after light irradiation. Near the sites of individual particles, the permeability of the cell membrane is modified, probably due to localized temperature changes. These results suggest that this laser-induced permeabilization strategy constitutes a new means of delivering exogenous materials into living cells.
authors.affiliation: School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Tatsunokuchi, Nomi-gun, Ishikawa 923-1292.
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Umebayashi
authors.forename: Yuuichi
authors.initials: Y
authors.lastname: Miyamoto
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Wakita
authors.forename: Akiko
authors.initials: A
authors.lastname: Kobayashi
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Nishisaka
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000378:metabolism* / Q000528:radiation effects*; D002463:Cell Membrane Permeability / Q000528:radiation effects*; D005110:Extracellular Space / Q000378:metabolism / Q000528:radiation effects; D005434:Flow Cytometry; D005452:Fluoresceins / Q000493:pharmacokinetics; D007834:Lasers; D051379:Mice; D008856:Microscopy, Fluorescence; D008863:Microspheres; D011419:Propidium / Q000493:pharmacokinetics; D013194:Staining and Labeling
chemical_list: D005452:Fluoresceins; D011419:Propidium; C018506:diacetylfluorescein