TY - JOUR
T1 - The lifetime evaluation of vapourised phase-change nano-droplets
AU - Ishijima, Ayumu
AU - Tanaka, Jun
AU - Azuma, Takashi
AU - Minamihata, Kosuke
AU - Yamaguchi, Satoshi
AU - Kobayashi, Etsuko
AU - Nagamune, Teruyuki
AU - Sakuma, Ichiro
N1 - Funding Information:
This work was supported by a grant for the Translational Systems Biology and Medicine Initiative from the Ministry of Education, Culture, Sports and Technology of Japan . We thank Kentaro Kikuchi for helping with the analysis, Kenichi Kawabata and Rei Asami for their kind consultations and providing PCNDs, and Yoshikazu Shibasaki and Shinya Yamahira for participating in the discussions related to the results.
Publisher Copyright:
© 2016 The Authors.
PY - 2016/7
Y1 - 2016/7
N2 - Phase-change nano-droplets (PCNDs) are sub-micron particles that are coated with phospholipid and contain liquid-state perfluorocarbons such as perfluoropentane (boiling point = 29°C) and perfluorohexane (boiling point = 57°C), which can vapourise upon application of ultrasound. The bubbles generated by such reactions can serve as ultrasound contrast agents or HIFU sensitisers. However, the lifetime of bubbles generated from PCNDs on μs-order is not well known. Knowledge of the condition of PCND-derived bubbles on μs-order is essential for producing bubbles customised for specific purposes. In this study, we use an optical measurement system to measure the vapourisation and stability of the bubbles (bubble-lifetime) as well as the stability-controlling method of the nucleated bubbles on μs-order while changing the internal composition of PCNDs and the ambient temperature. PCND-derived bubbles remain in a bubble state when the boiling point of the internal composition is lower than the ambient temperature, but lose their optical contrast after approximately 10 μs by re-condensation or dissolution when the boiling point of the internal composition is higher than the ambient temperature. We reveal that the superheating condition significantly affects the fate of vapourised PCNDs and that the bubble-lifetime can be controlled by changing both the ambient temperature conditions and the internal composition of PCNDs.
AB - Phase-change nano-droplets (PCNDs) are sub-micron particles that are coated with phospholipid and contain liquid-state perfluorocarbons such as perfluoropentane (boiling point = 29°C) and perfluorohexane (boiling point = 57°C), which can vapourise upon application of ultrasound. The bubbles generated by such reactions can serve as ultrasound contrast agents or HIFU sensitisers. However, the lifetime of bubbles generated from PCNDs on μs-order is not well known. Knowledge of the condition of PCND-derived bubbles on μs-order is essential for producing bubbles customised for specific purposes. In this study, we use an optical measurement system to measure the vapourisation and stability of the bubbles (bubble-lifetime) as well as the stability-controlling method of the nucleated bubbles on μs-order while changing the internal composition of PCNDs and the ambient temperature. PCND-derived bubbles remain in a bubble state when the boiling point of the internal composition is lower than the ambient temperature, but lose their optical contrast after approximately 10 μs by re-condensation or dissolution when the boiling point of the internal composition is higher than the ambient temperature. We reveal that the superheating condition significantly affects the fate of vapourised PCNDs and that the bubble-lifetime can be controlled by changing both the ambient temperature conditions and the internal composition of PCNDs.
UR - http://www.scopus.com/inward/record.url?scp=84963760753&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84963760753&partnerID=8YFLogxK
U2 - 10.1016/j.ultras.2016.04.002
DO - 10.1016/j.ultras.2016.04.002
M3 - Article
AN - SCOPUS:84963760753
SN - 0041-624X
VL - 69
SP - 97
EP - 105
JO - Ultrasonics
JF - Ultrasonics
ER -