**4. Applications**


**Figure 3.** *Liquid perfluorocarbon gene carrier.*

peptides, directed to the activated GP2B3A receptor of platelets, were evaluated for affinity to bind to activated platelets by testing for the inhibition of platelet aggregation.

In **Figure 3** the outer surface is stabilized by amphipathic lipid. Targeting ligands have been incorporated onto the head groups of the lipids. The genetic material is stabilized by cationic lipids. Electron microscopy studies have shown that the DNA is condensed as an electron-dense granule within the center of the nanoparticle. The diameter of these particles is about 100–200 nm [37]. There are several advantages to lipid shells. At the air-Space minimized, the phopspholipid's hydrophobic acyl chains face the phopspholipid's gas, and hydrophilic head groups face the water. Thus the monolayer will form around a newly trained gas bubble. Saturated diacyl phospholipids have very low surface tension below phase transition temperature. This is essential as surface tension at the curved interface induces a Laplace overpressure, thus forcing the gas core to dissolve [8]. The microbubble stabilizes at low tension which is achieved by the lipid monolayer [38]. Monolayers of lipids are highly cohesive and form solid-like character because of the attractive hydrophobic interaction between the tightly packed acyl chains and van der Waals [39]. These effect can be effective because the stability of microbubbles during sonication is not dependent on superoxide formation to facilitate disulfide bridging, as is the case with proteins. Therefore, as recently described by Stride and Edirisinghe, lipids are suitable for a variety of manufacturing techniques apart from sonication [40].

In the absence of ultrasound, if the adenovirus was administered with microbubbles using the same model, the author confirmed that plasmid transgene expression can be directed to the heart, with an even higher specificity than viral vectors and that this expression can be regulated by repeated treatments [41]. Lu et al. [42] have also shown that albumin-coated microbubbles significantly improved transgene expression in skeletal muscle of mice, even in the absence of ultrasound.
