Iron oxide nanoworms

Bhatia and coworkers established synthetic urinary biomarkers for detection of disease-specific protease activity with independence from the need for expensive machinery and an ease of interpretation [173,174]. They used activatable nanoprobes, producing lu-inary biomarkers readily detectable using a paper strip assay similar to a pregnancy test. Ihe luinary biomarkers are PEG-coated iron oxide nanoworms densely conjugated with fluorescein-labeled thrombin and MMP substrates, with high peptide density both for sensitivity and photoinduced fluorescence quenching. 

Figure 14.9. Artist s depiction of iron oxide nanoworms finding a tumor in the body. The worms are made of magnetic iron oxide coated with a biopolymer. The wormiike structure and a specialized coating allow these nanodevices to find and attach to tumors, improving our ability to find the tumor In an MR scan of the patient. Image from Popular Science, November 2008.

Most nanoparticles are recognized by the body s protective mechanisms as foreign objects. They are captured and removed from the bloodstream within minutes. A common trick is to coat the nanostructure with a biopolymer that allows the nanostructure to evade these natural elimination processes. In the case of iron oxide nanoworms, the biopolymer coating allows the materials to circulate in the body of a mouse for hours. 

Park, J.-H. Maltzahn, G. A. V. Zhang, L. Schwartz, M. R Bhatia, S. R Ruoslahti, E. Sailor, M. J. Magnetic iron oxide nanoworms for tumor targeting and imaging. Advanced Materials 2008,20,1630-1635. 

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