However, soluble carriers remain plagued with limited load-carrying capacity, lack of protection for the bounded therapeutics, and covalent linkage chemistry that may alter drug efficacy. As such, soluble carriers can have
limitations for drug delivery but still be beneficial for imaging application and gene delivery. Viral nanoparticles are advantageous due to their selleck chem Idelalisib natural ability to avoid detection and clearance from the bloodstream, their innate targeting capability, and their ability to enter cells. For example, the cowpea mosaic virus (CPMV) may be used for vascular imaging and drug delivery due Inhibitors,research,lifescience,medical to its specific binding to vimentin, which is presented on endothelial cells during angiogenesis and also present during neovascularization of the vasa vasorum in atherosclerosis.20 21 Additionally, imaging of CPMV has shown their localization
to inflamed endothelium.22 PEGylation of CPMV may permit the use of these viruses for other targets.23 The drawbacks to such nanoparticles are potential toxicity in humans and the requirement Inhibitors,research,lifescience,medical for them to be engineered and grown in bioreactors, which adds to the complexity of their design. Several lipid-based nanovectors such as liposomes, micelles, and lipoproteins have been proposed for targeted drug delivery and imaging. Liposomes, phospholipid-based nanovesicles, are easy to fabricate and possess low toxicity and large versatility. Liposomes can be loaded with hydrophilic, hydrophobic, Inhibitors,research,lifescience,medical and lipophilic drugs for therapeutic applications. For diagnostic applications, contrast-generating material can be incorporated in the outer shell or entrapped within the core. For example, a group Inhibitors,research,lifescience,medical at Washington
University School of Medicine has engineered a targeted paramagnetic nanoemulsion for molecular imaging of atherosclerotic plaques with MRI.9 24 The nanoemulsion consists of a liquid perfluorocarbon core coated with a lipid shell that contains gadolinium. Unfortunately, issues of gadolinium toxicity have been raised that may limit the utility of the paramagnetic nanoemulsion. Alternatively, perfluorocarbon nanoemulsions have been used for ultrasound-based molecular imaging Inhibitors,research,lifescience,medical of atherosclerosis.25 However, the nanoemulsions are weak scatterers due to their size and the incompressibility of the liquid core, and thus a large number of nanoemulsions are required in order to produce a detectable change in image contrast. Ideally, ultrasound contrast agents will contain gas, which is more compressible Cilengitide than liquid and thus is more echogenic. Liposomes containing liquid and gas have been engineered for ultrasound-based molecular imaging of several components of selleck products atheromas, including fibrin and adhesion molecules.26 27 In addition to imaging, ultrasound can be used to trigger the release of entrapped thrombolytic agents from echogenic liposomes.28 29 Thus, echogenic liposomes can serve as a nanovector platform for targeted image-guided drug delivery and treatment of thrombi.