Synchronized Optical and Acoustic Droplet Vaporization for Effective Sonoporation
Journal
Pharmaceutics
Journal Volume
11
Journal Issue
6
Date Issued
2019
Author(s)
Abstract
Inertial cavitation-based sonoporation has been utilized to enhance treatment delivery effcacy. In our previous study, we demonstrated that tumor therapeutic effcacy can be enhanced through vaporization-assisted sonoporation with gold nanodroplets (AuNDs). Specifically, the AuNDs were vaporized both acoustically (i.e., acoustic droplet vaporization, ADV) and optically (i.e., optical droplet vaporization, ODV). A continuous wave (CW) laser was used for ODV in combination with an ultrasound pulse for ADV. Although effective for vaporization, the use of a CW laser is not energy effcient and may create unwanted heating and concomitant tissue damage. In this study, we propose the use of a pulsed wave (PW) laser to replace the CW laser. In addition, the PW laser was applied at the rarefaction phase of the ultrasound pulse so that the synergistic effects of ADV and ODV can be expected. Therefore, a significantly lower laser average power can be expected to achieve the vaporization threshold. Compared to the CW laser power at 2W/cm2 from the previous approach, the PW laser power was reduced to only 0.2404 W/cm2. Furthermore, we also demonstrate in vitro that the sonoporation rate was increased when the PW laser was applied at the rarefaction phase. Specifically, the vaporization signal, the inertial cavitation signal, and the sonoporation rate all displayed a 1-μs period, which corresponded to the period of the 1-MHz acoustic wave used for ADV, as a function of the relative laser delay. The increased sonoporation rate indicates that this technique has the potential to enhance sonoporation-directed drug delivery and tumor therapy with a lower laser power while keeping the cell death rate at the minimum. Photoacoustic imaging can also be performed at the same time since a PW laser is used for the ODV. © 2019 by the authors. Licensee MDPI, Basel, Switzerland.
Subjects
acoustic droplet vaporization; cavitation; nanodroplets; optical droplet vaporization; sonoporation
SDGs
Other Subjects
gold nanodroplet; nanoparticle; unclassified drug; acoustic analysis; acoustic droplet vaporization; acoustics; Article; cell death; nanoencapsulation; optical droplet vaporization; photoacoustics; physical chemistry; physical parameters; pressure measurement; pulse wave; pulsed wave laser; signal detection; sonoporation; vaporization
Type
journal article