Abstract
Localized delivery could decrease the systemic side effects of toxic chemotherapy drugs. The unique delivery agents we examine consist of microbubbles with an outer lipid coating, an oil layer, and a perfluorobutane gas core. These structures are 0.5-12 μm in radius at rest. Oil layers of these acoustically active lipospheres (AALs) range from 0.3-1.5 μm in thickness and thus the agents can carry a large payload compared to nano-scale drug delivery systems. We show that triacetin-based drug-delivery vehicles can be fragmented using ultrasound. Compared with a lipid-shelled contrast agent, the expansion of the drug-delivery vehicle within the first cycle is similar, and a subharmonic component is demonstrated at an equivalent radius, frequency, and driving pressure. For the experimental conditions explored here, the pulse length required for destruction of the drug-delivery vehicle is significantly greater, with at least five cycles required, compared with one cycle for the contrast agent. For the drug-delivery vehicle, the observed destruction mechanism varies with the initial radius, with microbubbles smaller than resonance size undergoing a symmetric collapse and producing a set of small, equal-sized fragments. Between resonance size and twice resonance size, surface waves become visible, and the oscillations become asymmetrical. For agents larger than twice the resonance radius, the destruction mechanism changes to a pinch-off, with one fragment containing a large fraction of the original volume.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 1400-1410 |
| Number of pages | 11 |
| Journal | IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control |
| Volume | 49 |
| Issue number | 10 |
| DOIs | |
| State | Published - Oct 2002 |
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ASJC Scopus subject areas
- Electrical and Electronic Engineering
- Acoustics and Ultrasonics
Cite this
Dynamics and fragmentation of thick-shelled microbubbles. / May, Donovan J.; Allen, John S.; Ferrara, Katherine W.
In: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, Vol. 49, No. 10, 10.2002, p. 1400-1410.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Dynamics and fragmentation of thick-shelled microbubbles
AU - May, Donovan J.
AU - Allen, John S.
AU - Ferrara, Katherine W.
PY - 2002/10
Y1 - 2002/10
N2 - Localized delivery could decrease the systemic side effects of toxic chemotherapy drugs. The unique delivery agents we examine consist of microbubbles with an outer lipid coating, an oil layer, and a perfluorobutane gas core. These structures are 0.5-12 μm in radius at rest. Oil layers of these acoustically active lipospheres (AALs) range from 0.3-1.5 μm in thickness and thus the agents can carry a large payload compared to nano-scale drug delivery systems. We show that triacetin-based drug-delivery vehicles can be fragmented using ultrasound. Compared with a lipid-shelled contrast agent, the expansion of the drug-delivery vehicle within the first cycle is similar, and a subharmonic component is demonstrated at an equivalent radius, frequency, and driving pressure. For the experimental conditions explored here, the pulse length required for destruction of the drug-delivery vehicle is significantly greater, with at least five cycles required, compared with one cycle for the contrast agent. For the drug-delivery vehicle, the observed destruction mechanism varies with the initial radius, with microbubbles smaller than resonance size undergoing a symmetric collapse and producing a set of small, equal-sized fragments. Between resonance size and twice resonance size, surface waves become visible, and the oscillations become asymmetrical. For agents larger than twice the resonance radius, the destruction mechanism changes to a pinch-off, with one fragment containing a large fraction of the original volume.
AB - Localized delivery could decrease the systemic side effects of toxic chemotherapy drugs. The unique delivery agents we examine consist of microbubbles with an outer lipid coating, an oil layer, and a perfluorobutane gas core. These structures are 0.5-12 μm in radius at rest. Oil layers of these acoustically active lipospheres (AALs) range from 0.3-1.5 μm in thickness and thus the agents can carry a large payload compared to nano-scale drug delivery systems. We show that triacetin-based drug-delivery vehicles can be fragmented using ultrasound. Compared with a lipid-shelled contrast agent, the expansion of the drug-delivery vehicle within the first cycle is similar, and a subharmonic component is demonstrated at an equivalent radius, frequency, and driving pressure. For the experimental conditions explored here, the pulse length required for destruction of the drug-delivery vehicle is significantly greater, with at least five cycles required, compared with one cycle for the contrast agent. For the drug-delivery vehicle, the observed destruction mechanism varies with the initial radius, with microbubbles smaller than resonance size undergoing a symmetric collapse and producing a set of small, equal-sized fragments. Between resonance size and twice resonance size, surface waves become visible, and the oscillations become asymmetrical. For agents larger than twice the resonance radius, the destruction mechanism changes to a pinch-off, with one fragment containing a large fraction of the original volume.
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UR - http://www.scopus.com/inward/citedby.url?scp=0036771562&partnerID=8YFLogxK
U2 - 10.1109/TUFFC.2002.1041081
DO - 10.1109/TUFFC.2002.1041081
M3 - Article
C2 - 12403141
AN - SCOPUS:0036771562
VL - 49
SP - 1400
EP - 1410
JO - IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
JF - IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
SN - 0885-3010
IS - 10
ER -