Development and characterization of a nano-sized surfactant stabilized contrast agent for diagnostic ultrasound

Abstract

Absfracf -ST68 is a surfactant based contrast agent being used to enhance diagnostic ultrasound imaging as well as develop a technique for targeting. The sue of the ST68 nanohnbhles is being reduced in order to facilitate passage through tumor blood vessel pores. Different sonication times are being investigated in order to determine the smallest s e of the nanobuhhles. The contrast agent is characterized hy dynamic light scattering and acoustic dose response to develop the maximum enhancement.

A History of Nanobubbles

“…2003: The use of bulk nanobubbles as ultrasound contrast agents was reported. 6 Illustration: Fluorescence microscopy image of cells incubated with nanobubbles reprinted from ref 7. 2006: The influence of salt and surfactants on the shape and size of surface nanobubbles was shown to be negligible, thus indicating that the stabilization of surface nanobubbles was unlikely because of contaminants.…”

“…Oxygenation using nanobubbles is also being applied to the bioremediation of groundwater pollution and water treatment. , Bulk nanobubbles are finding biological and medical applications. Bubbles are effective ultrasound contrast agents because of their extremely low density and their nonlinear response to ultrasound. ,− Nanosized bubbles are preferred in some applications as they can be used to target the capillaries outside the pulmonary bed . Nanobubbles or related entities have also been implicated in oxygenated medical saline for the treatment of asthma and other autoimmune diseases with remarkable efficacy. − Hydrogen nanobubbles are also present in health drinks that employ a cathodic stream from electrolysis. , Nanobubbles have also been implicated in the disruption of water transport due to hydraulic failure in the xylem of trees …”

“…Illustration: surface nanobubbles on mica, in water, imaged in tapping mode by AFM, reprinted from ref . 2003: The use of bulk nanobubbles as ultrasound contrast agents was reported . Illustration: Fluorescence microscopy image of cells incubated with nanobubbles reprinted from ref .…”

Breaking free from vascular confinement: status and prospects for submicron ultrasound contrast agents

“…However, many reports of nanobubbles have now been made for intravascular and extravascular imaging applications, 30,[33][34][35][36][37][38][39][40][41] demonstrating both stability and signal from size isolated subpopulations or interesting alternative shell components, such as the copolymer Pluronic proposed by Krupka et al, 30 new ones to meet these demands. However, uneven angiogenic signaling from the tumor results in vessels abnormal in form and architecture, characterized by haphazard dilated, tortuous channels lacking the organization and hierarchy of healthy blood vessels.…”

“…However, many reports of nanobubbles have now been made for intravascular and extravascular imaging applications, demonstrating both stability and signal from size isolated subpopulations or interesting alternative shell components, such as the copolymer Pluronic proposed by Krupka et al, which controlled bubble size, enhanced stability and echogenicity, and acted as a chemo‐ and thermal‐sensitizer by altering target cell membrane fluidity. Generally, there are two explanations for the seemingly anomalous observations of nanobubbles: First, the thick polymer or thin surfactant‐based encapsulating layer introduced in the second generation of bubbles can facilitate the generation of nonlinear signals above a pressure threshold .…”