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Evolution of contrast agents for ultrasound imaging and ultrasound-mediated drug delivery.

Paefgen V, Doleschel D, Kiessling F - Front Pharmacol (2015)

Bottom Line: Bubbles can also be loaded with or attached to drugs, peptides or genes and can be destroyed by US pulses to locally release the entrapped agent.Recent studies show that US CAs are also valuable tools in hyperthermia-induced ablation therapy of tumors, or can increase cellular uptake of locally released drugs by enhancing membrane permeability.Additionally, an overview of the recent developments in US probe design for functional and molecular diagnosis as well as for drug delivery is given.

View Article: PubMed Central - PubMed

Affiliation: Institute for Experimental Molecular Imaging, RWTH Aachen University Hospital, Aachen Germany.

ABSTRACT
Ultrasound (US) is one of the most frequently used diagnostic methods. It is a non-invasive, comparably inexpensive imaging method with a broad spectrum of applications, which can be increased even more by using bubbles as contrast agents (CAs). There are various different types of bubbles: filled with different gases, composed of soft- or hard-shell materials, and ranging in size from nano- to micrometers. These intravascular CAs enable functional analyses, e.g., to acquire organ perfusion in real-time. Molecular analyses are achieved by coupling specific ligands to the bubbles' shell, which bind to marker molecules in the area of interest. Bubbles can also be loaded with or attached to drugs, peptides or genes and can be destroyed by US pulses to locally release the entrapped agent. Recent studies show that US CAs are also valuable tools in hyperthermia-induced ablation therapy of tumors, or can increase cellular uptake of locally released drugs by enhancing membrane permeability. This review summarizes important steps in the development of US CAs and introduces the current clinical applications of contrast-enhanced US. Additionally, an overview of the recent developments in US probe design for functional and molecular diagnosis as well as for drug delivery is given.

No MeSH data available.


Related in: MedlinePlus

Behavior of SS-MB (lipid) and HS-MB (polymer) at different US intensities (modified from Hernot and Klibanov, 2008).
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Figure 1: Behavior of SS-MB (lipid) and HS-MB (polymer) at different US intensities (modified from Hernot and Klibanov, 2008).

Mentions: Soft-shell MB are commonly used for examinations using a low mechanical index (MI) since these MB are sensitively detectable by their non-linear oscillations. The better oscillation properties of SS-MB compared with HS-MB are due to the thinner, more flexible shells, which are held together not by covalent bonding, but hydrophobic interactions. Therefore, after slight shell disruptions, the shell seals itself to minimize surface tension (Borden et al., 2005; Brismar et al., 2012). If sealing is not possible due to the high acoustic pressure, the MB will split into several smaller bubbles instead of bursting like HS-MB (Figure 1). To achieve optimal contrast, the shells’ characteristics should be considered and the acoustic power adjusted to the type of MB (Leong-Poi et al., 2002).


Evolution of contrast agents for ultrasound imaging and ultrasound-mediated drug delivery.

Paefgen V, Doleschel D, Kiessling F - Front Pharmacol (2015)

Behavior of SS-MB (lipid) and HS-MB (polymer) at different US intensities (modified from Hernot and Klibanov, 2008).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4584939&req=5

Figure 1: Behavior of SS-MB (lipid) and HS-MB (polymer) at different US intensities (modified from Hernot and Klibanov, 2008).
Mentions: Soft-shell MB are commonly used for examinations using a low mechanical index (MI) since these MB are sensitively detectable by their non-linear oscillations. The better oscillation properties of SS-MB compared with HS-MB are due to the thinner, more flexible shells, which are held together not by covalent bonding, but hydrophobic interactions. Therefore, after slight shell disruptions, the shell seals itself to minimize surface tension (Borden et al., 2005; Brismar et al., 2012). If sealing is not possible due to the high acoustic pressure, the MB will split into several smaller bubbles instead of bursting like HS-MB (Figure 1). To achieve optimal contrast, the shells’ characteristics should be considered and the acoustic power adjusted to the type of MB (Leong-Poi et al., 2002).

Bottom Line: Bubbles can also be loaded with or attached to drugs, peptides or genes and can be destroyed by US pulses to locally release the entrapped agent.Recent studies show that US CAs are also valuable tools in hyperthermia-induced ablation therapy of tumors, or can increase cellular uptake of locally released drugs by enhancing membrane permeability.Additionally, an overview of the recent developments in US probe design for functional and molecular diagnosis as well as for drug delivery is given.

View Article: PubMed Central - PubMed

Affiliation: Institute for Experimental Molecular Imaging, RWTH Aachen University Hospital, Aachen Germany.

ABSTRACT
Ultrasound (US) is one of the most frequently used diagnostic methods. It is a non-invasive, comparably inexpensive imaging method with a broad spectrum of applications, which can be increased even more by using bubbles as contrast agents (CAs). There are various different types of bubbles: filled with different gases, composed of soft- or hard-shell materials, and ranging in size from nano- to micrometers. These intravascular CAs enable functional analyses, e.g., to acquire organ perfusion in real-time. Molecular analyses are achieved by coupling specific ligands to the bubbles' shell, which bind to marker molecules in the area of interest. Bubbles can also be loaded with or attached to drugs, peptides or genes and can be destroyed by US pulses to locally release the entrapped agent. Recent studies show that US CAs are also valuable tools in hyperthermia-induced ablation therapy of tumors, or can increase cellular uptake of locally released drugs by enhancing membrane permeability. This review summarizes important steps in the development of US CAs and introduces the current clinical applications of contrast-enhanced US. Additionally, an overview of the recent developments in US probe design for functional and molecular diagnosis as well as for drug delivery is given.

No MeSH data available.


Related in: MedlinePlus