Liquid Perfluorocarbons as Contrast Agents for Ultrasonography and 19F-MRI

Abstract

Perfluorocarbons (PFCs) are fluorinated compounds that have been used for many years in clinics mainly as gas/oxygen carriers and for liquid ventilation. Besides this main application, PFCs have also been tested as contrast agents for ultrasonography and magnetic resonance imaging since the end of the 1970s. However, most of the PFCs applied as contrast agents for imaging were gaseous. This class of PFCs has been recently substituted by liquid PFCs as ultrasound contrast agents. Additionally, liquid PFCs are being tested as contrast agents for (19)F magnetic resonance imaging (MRI), to yield dual contrast agents for both ultrasonography and (19)F MRI. This review focuses on the development and applications of the different contrast agents containing liquid perfluorocarbons for ultrasonography and/or MRI: large and small size emulsions (i.e. nanoemulsions) and nanocapsules.

Design of protein homocystamides with enhanced tumor uptake properties for 19F magnetic resonance imaging

“…[36][37][38][39][40][41] Emulsions and nano-systems encapsulating liquid perfluorocarbons (PFCs) as contrast agents for MRI have proven their potentialities for the imaging of blood pool, ventricular abnormalities, liver, thrombi, atherosclerosis, mononuclear phagocyte system, tumor, molecular imaging of angiogenesis and drug delivery carriers of anticancer drugs. However, the use of PFC emulsions is limited due to their heterogeneity, instability, split 19 F signals, as well as excessive retention within internal organs (liver, spleen, lung) for a prolonged period of time.…”

A Nonpolar, Nonamphiphilic Molecule Can Accelerate Adsorption of Phospholipids and Lower Their Surface Tension at the Air/Water Interface

“…These include use of injectable microbubble contrast agents [1][2][3] and emulsions for oxygen delivery, [4][5][6] drug delivery, and diagnostics. [7,8] In particular, most of the commercially available injectable soft-shell bubbles contain a perfluoro compound in the gas phase. [3,[9][10][11][12] In these systems, monolayers of PLs generally constitute the bubble or emulsion droplet walls.…”

“…As a consequence, although the isolated PFH molecule has no amphiphilic character, it nevertheless displays some surface activity. The efficacy of PFH in terms of decreasing the g eq value of DiC 8 -PC at the interface was quantified by using the difference, Dg eq = g eq (air)Àg eq (PFH), between the equilibrium interfacial tensions measured at the air/DiC 8 ) was reached ( Figure 2). This indicates that, when the PL concentration increases, it eventually overwhelms the tension lowering effect of PFH.…”

“…This fit, in a first step, allowed the following parameters for DiC 8 -PC alone to be calculated: the area occupied by one DiC 8 -PC molecule at the air/buffer interface, w 1 (0.6 nm 2 ), the adsorption equilibrium constant, b 1 (3.85 10 4 L mmol…”

Targeted and ultrasound-triggered cancer cell injury using perfluorocarbon emulsion-loaded liposomes endowed with cancer cell-targeting and fusogenic capabilities

“…It was speculated that cancer cells were injured by the following sequence of events: (i) avidin-mediated liposome binding to target cancer cells; (ii) subsequent HVJ envelope-mediated liposome fusion to cells, resulting in internalization of PFC5 emulsion droplets directly into the cytosol; and (iii) ultrasound-mediated vaporization of PFC5 emulsion droplets within cells, damaging cancer cells physically from the inside. PFC emulsions have been used for ADV in medical applications, including use as a contrast agent in sonography [33]. These emulsions remain stable in the liquid phase even at temperatures above their normal boiling points as long as they are sufficiently small [34].…”