Application of Nanoparticles in Diagnostic Imaging via Ultrasonography

The effectiveness of an imaging technique not only depends on its ability to image quantitatively both morphological and physiological functions of the tissue, but also on the contrast agent used to communicate with biomolecules. Several types of contrast media are used in medical imaging and they can roughly be cataloged based on the imaging modalities where they are used. More importantly, the use of contrast agent with their size ranging in nanometer scale has become general practice in medical diagnosis. As the matter of fact, nanoparticles have fascinated scientist for over a century and are now heavily utilized in biomedical sciences and engineering as they are long known to communicate effectively with the biomolecules. Today these materials can be synthesized and modified with various chemical functional groups which allow them to be conjugated with antibodies, ligands, and drugs of interest and thus opening a wide range of potential applications in biotechnology, and more importantly in diagnostic medical imaging via ultrasound, computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET). These imaging modalities differ not only in resolution, but also in the instrumentation and the type of nanoparticle that can be employed as its assistant. Of these imaging techniques, ultrasound is one of the oldest imaging modality which is still widely used to examine internal organs of the body and diagnose potential disease states such as cancer, plague, clots, and swelling. Various articles have been published over the period of years detailing the instrumentation and the applications of ultrasonography, but very few have emphasized the importance of particle size in developing a successful contrast agent for ultrasonography. Thus in the present review article we aim to present the basic principles involved in developing successful contrast agent for Ultrasound imaging. Furthermore, we have also discussed the experimental and physical aspects of various types of nanoparticles including its fabrication and design of targeted contrast agents. Finally, we have cited some of the best biomedical and clinical applications of the developed nanoprobes and their use for Ultrasound imaging.