The effect of acoustically-induced cavitation on the permeance of a bullfrog urinary bladder

Abstract

It is well known that ultrasound enhances drug delivery to tissues, although there is not a general consensus about the responsible mechanisms. However, it is known that the most important factor associated with ultrasonically-enhanced drug permeance through tissues is cavitation. Here we report results from research conducted using a experimental approach adapted from single bubble sonoluminescence experiments which generates very well defined acoustic fields and allows controlled activation and location of cavitation. The experimental design requires that a biological tissue be immersed inside a highly degassed liquid media to avoid random bubble nucleation. Therefore, live frog bladders were used as the living tissue due to their high resistance to hypoxia. Tissue membrane permeance was measured using radiolabeled urea. The results show that an increase in tissue permeance only occurs when cavitation is present near the tissue membrane. Moreover, confocal microscopy shows a direct correlation between permeance increases and physical damage to the tissue.

Low‐power gas microbubble detection technology based on acoustic resonance

“…The concept applied for bubble detection was originally tested in a resonant acoustic chamber designed by our group. 9,33,34 Briefly, this acoustic chamber consists of a cylindrical borosilicate glass with a diameter of 95 and 300 mm in length, sandwiched between two square acrylic flanges where all required fittings for fluid and bubble injection are installed. Two off centered 8 mm vinyl tubes run the length of the glass cylinder where bubbles can be injected, and the rest of the chamber is filled with degassed water.…”

“…Gas bubble detection is a critical component of the instrumentation needed in many industrial and medical processes as well as in fundamental research of two-phase flow systems, cavitation phenomena, sonochemistry, sonoluminescence, and even biophysics of gene transport. [1][2][3][4][5][6][7][8][9] Real-time information and detection of bubble populations are required for most filling operations in the paint, food, detergent, and cosmetic industries where bubbles can compromise the final product. 10,11 In Ecology and Climate Science, bubble detection technology is required to understand the flux of greenhouse gasses, such as methane and carbon dioxide, between the ocean and the atmosphere.…”

Experiments with nano-scaled helium bubbles in water subjected to standing acoustic fields

“…The acoustic chamber shown in Fig.2 has been described in detail by Cancelos et al, (2010) and it consists of a Pyrex TM glass cylinder wall with 94.5mm in outer diameter, 145.4mm in height and 2.5mm thickness. The glass cylinder is belted at middle height by a piezoelectric ring (PZT) polarized in the radial direction (C5400, Channel Industries, Santa Barbara, CA,USA, shown with a yellow plastic cover in Fig.…”