The use of peruorocarbon lled droplets for use as Phase Changing Contrast Agents (PCCAs) is a promosing eld. These capsules also have potential to be used for mediated drug delivery. The phase change, which has given the capsules their name, is the process when the capsule transforms from a droplet into a bubble. This process is referred to as Acoustic Droplet Vaporization (ADV) and can be induced with the use of ultrasonic waves. In this study a new type of Perfluorpentane (PFC5) capsules which are stabilized with Cellulose Nano Fibers (CNF) have been evaluated for its potential as a PCCA. To investigate this potential a setup was designed in which the capsules could be exposed to ultrasound waves. Following the ultrasound exposure the capsules were visualized under a light transmission microscope. The experiments were conducted for dierent combinations of ultrasound parameters. For each combination eight volume distributions were created, in which two of them as reference cases were not exposed to ultrasound waves. Six cases with the ultrasound ring with different levels of acoustic power, resulting in peak negative pressures ranging from 0.144 to 0.291 MPa. The results showedfthat ADV could be observed when the frequency of the acoustic wave is 3.5 MHz, the pulse repetition frequency is 500 and the burst width is set to 12 cycles. The Peak Negative Pressure (PNP)-threshold for ADV is about 0.200 MPa. When the burst width is set to 8, ADV is also observed however to a lesser extent then when it is set to 12. These results indicate that the CNF-stabilized PFC5 capsules are promising droplets with a potential future as an alternative to currently used PCCAs.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:kth-253360 |
| Date | January 2019 |
| Creators | Nimander, Didrik |
| Publisher | KTH, Skolan för kemi, bioteknologi och hälsa (CBH) |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | TRITA-CBH-GRU ; 2019:085 |
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