title: Temporal effect of inertial cavitation with and without microbubbles on surface deformation of agarose S gel in the presence of 1-MHz focused ultrasound.
abstract: Sonoporation has the potential to deliver extraneous molecules into a target tissue non-invasively. There have been numerous investigations of cell membrane permeabilization induced by microbubbles, but very few studies have been carried out to investigate sonoporation by inertial cavitation, especially from a temporal perspective. In the present paper, we show the temporal variations in nano/micro-pit formations following the collapse of inertial cavitation bubbles, with and without Sonazoid® microbubbles. Using agarose S gel as a target material, erosion experiments were conducted in the presence of 1-MHz focused ultrasound applied for various exposure times, Tex (0.002-60 s). Conventional microscopy was used to measure temporal variations in micrometer-scale pit numbers, and atomic force microscopy utilized to detect surface roughness on a nanometer scale. The results demonstrated that nanometer-scale erosion was predominantly caused by Sonazoid® microbubbles and C4F10 gas bubbles for 0.002 s<Tex<1 s, while the number of micrometer-scale pits, caused mainly by inertial cavitation bubbles such as C4F10 gas bubbles and vapor bubbles, increased exponentially with increasing Tex in the range 0.1 s<Tex<10 s. The results of the present study suggest that cavitation-induced sonoporation can produce various pore sizes in membranes, enabling the delivery of external molecules of differing sizes into cells or tissues.
authors.affiliation: Faculty of Education, Hokkaido University of Education, Hakodate, Hokkaido 040-8567, Japan. Electronic address: tomita.yukio@h.hokkyodai.ac.jp.
authors.forename: Y
authors.initials: Y
authors.lastname: Tomita
authors.affiliation: Faculty of Education, Hokkaido University of Education, Hakodate, Hokkaido 040-8567, Japan. Electronic address: matsuura.toshihiko@h.hokkyodai.ac.jp.
authors.forename: T
authors.initials: T
authors.lastname: Matsuura
authors.affiliation: Graduate School of Biomedical Engineering, Tohoku University, 4-1 Seiryo, Aoba-ku, Sendai 980-8575, Japan. Electronic address: kodama@bme.tohoku.ac.jp.
authors.forename: T
authors.initials: T
authors.lastname: Kodama
mesh_terms: D002462:Cell Membrane; D005782:Gels; D045423:Microbubbles; D012685:Sepharose; D013010:Sonication; D013499:Surface Properties; D014465:Ultrasonics
chemical_list: D005782:Gels; D012685:Sepharose
keywords: Inertial cavitation; Microbubbles; Sonoporation; Surface roughness; Ultrasound