Noninvasive Imaging Techniques of Metal Nanoparticles and Their Future Diagnostic Applications

Abstract

Bio-imaging offers visualization of complex living systems for clinical diagnosis and detection of the diseases. The critical challenges that are associated with conventional contrasting agents or imaging probes are toxic effects and shorter circulation time in the body. Therefore, bio-imaging requires advancements in imaging probes and contrast agents for better understanding of the biological architectures to diagnose the disease. Recent advancements of nanoscience and nanotechnology have changed the paradigm of bio-imaging by providing the better resolution, high contrast images to diagnose the diseases at the molecular level. Also, nanotechnology offers the theranostic approach to diagnose and treat the disease using various nanomaterials that are functionalized with imaging agents and therapeutic molecules. In fact, various imaging techniques are now employing nanomaterials as sole source of imaging signal rather using as contrast objective. The present review article mainly focuses on the application of various nanomaterials in imaging modalities including MRI (magnetic resonance imaging), Raman based, luminescence upconversion imaging, CT (computed tomography), fluorescence imaging, etc. Additionally, we also review the recent advancements that occurred with the help of nanomaterials in each of these imaging techniques. Further, present clinical status of nanomaterials as imaging agents will also be discussed. We conclude with the various challenges associated with nanomaterials for clinical translation as imaging agents. Finally, we focus the insights of nanoparticle-based bio-imaging for future diagnostic applications.