Adjustment of Ultrasound Exposure Duration to Microbubble Sonodestruction Kinetics for Optimal Cell Sonoporation In Vitro

Abstract

Cell sonoporation enables the delivery of various exogenous molecules into the cells. To maximize the percentage of reversibly sonoporated cells and to increase cell viability we propose a model for implicit dosimetry for adjustment of ultrasound (US) exposure duration. The Chinese hamster ovary cell suspension was supplemented with microbubbles (MB) and exposed to US, operating at the frequency of 880kHz, with a 100% duty cycle and with an output peak negative pressure (PNP) of 500kPa for durations ranging from 0.5 to 30s. Using diagnostic B-scan imaging we showed that the majority of the MB at 500kPa US peak negative pressure undergo sonodestruction in less than a second. During this time maximal number of reversibly sonoporated cells was achieved. Increase of US exposure duration did not increase sonoporated cell number, however it induced additional cell viability decrease. Therefore aiming to achieve the highest level of reversibly sonoporated cells and also to preserve the highest level of cell viability, the duration of US exposure should not exceed the duration needed for complete MB sonodestruction.

Bleomycin delivery into cancer cellsin vitrowith ultrasound and SonoVue® or BR14® microbubbles

“…Since BLM is comparable in size with these molecules (MW $1.5 kDa), BLM can also enter the cells through the US and MB-induced pores [22]. The duration of intracellular uptake is dependent on the transient pore existence time, which could last from a few seconds [30,31,33] up to 10 min [21]. Alternatively, it was also proposed that mechanism for BLM internalization is a receptor mediated endocytosis and requires specific membrane proteins for BLM binding [5].…”

“…In our previous study, we have proposed that sonoporation can be related to MB sonodestruction [21]. In response to applied US, the inertial cavitation is characterized by a sudden expansion and rapid collapse of gas MBs resulting in their disappearance (sonodestruction).…”

“…The great variation in US parameters indicates that they are selected largely empirically. Recently, we proposed that sonoporation can be related to MB sonodestruction [21]. Thus, the aim of our study was to analyze the efficiency of BLM delivery into human tumor cells in response to MB sonodestruction.…”

Acoustic Estimation of Resonance Frequency and Sonodestruction of SonoVue Microbubbles

“…2). The decrease of attenuation coefficient was shown to reflect MB sonodestruction (Casciaro et al, 2007) and makes it possible to use this parameter for estimation of MB sonodestruction kinetics (Tamosiunas et al, 2012). …”

Enhancement of Adenovirus Delivery after Ultrasound-Stimulated Therapy in a Cancer Model

“…Although there is some evidence disputing the exact duration of this effect, this therapeutic stimulation has been shown to last up to 30 min post-US exposure (Sorace et al 2013). Depending on the US setup and variance between US parameters used for US therapy, differences in sustained permeability have been found on the order of minutes to hours, and there have even been permanent non-reversible reactions (Böhmer et al 2010; Caskey et al 2009; Chin et al 2009; Stieger et al 2007; Tamosi unas et al 2012). US-stimulated therapy has been increasingly popular in pre-clinical models because it is generally non-invasive and has significant potential for translation.…”