Enzyme-Degradable Hybrid Polymer/Silica Microbubbles as Ultrasound Contrast Agents
The fabrication of an enzyme-degradable polymer/silica hybrid microbubble is reported that produces an ultrasound contrast image. The polymer, a triethoxysilane end-capped polycaprolactone (SiPCL), is used to incorporate enzyme-degradable components into a silica microbubble synthesis, and to impart...
| Veröffentlicht in: | Langmuir : the ACS journal of surfaces and colloids. - 1985. - 32(2016), 25 vom: 28. Juni, Seite 6534-43 |
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| Format: | Online-Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2016
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| Zugriff auf das übergeordnete Werk: | Langmuir : the ACS journal of surfaces and colloids |
| Schlagworte: | Journal Article Contrast Media Polyesters Polystyrenes Silanes polycaprolactone 24980-41-4 Silicon Dioxide 7631-86-9 triethoxysilane mehr... |
| Zusammenfassung: | The fabrication of an enzyme-degradable polymer/silica hybrid microbubble is reported that produces an ultrasound contrast image. The polymer, a triethoxysilane end-capped polycaprolactone (SiPCL), is used to incorporate enzyme-degradable components into a silica microbubble synthesis, and to impart increased elasticity for enhanced acoustic responsiveness. Formulations of 75, 85, and 95 wt % SiPCL in the polymer feed produced quite similar ratios of SiPCL and silica in the final bubble but different surface properties. The data suggest that different regions of the microbubbles were SiPCL-rich: the inner layer next to the polystyrene template core and the outer surface layer, thereby creating a sandwiched silica-rich layer of the bubble shell. Overall, the thickness of the microbubble shell was dependent on the starting TEOS concentration and the reaction time. Despite the layered structure, the microbubble could be efficiently degraded by lipase enzyme, but was stable without enzyme. The ultrasound contrast showed a general trend of increase in image intensity with SiPCL feed ratio, although the 95 wt % SiPCL bubbles did not produce a contrast image, probably due to bubble collapse. At higher normalized peak negative acoustic pressure (mechanical index, MI), a nonlinear frequency response also emerges, characterized by the third harmonic at around 3f0, and increases with MI. The threshold MI transition from linear to nonlinear response increased with decrease in SiPCL |
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| Beschreibung: | Date Completed 05.06.2018 Date Revised 05.06.2018 published: Print-Electronic Citation Status MEDLINE |
| ISSN: | 1520-5827 |
| DOI: | 10.1021/acs.langmuir.6b01075 |