Chemical Strategies for the Development of Multimodal Imaging Probes Using Nanoparticles

This chapter focuses on the most recently reported nanoparticle agents that have been demonstrated in vivo. It describes the general methods of chemical conjugations, silanisation, and electrostatic adsorption. The chapter examines the recent use of nanoparticles that incorporate a fluorescent dye and a magnetic nanoparticle together. The combination of near-infrared (NIR) and magnetic resonance imaging (MRI) modalities and in vivo characterisation has been executed in two ways: attaching an organic NIR dye to a superparamagnetic iron oxide nanoparticle (SPION); and combining SPIONs with a materials-based NIR fluorescent species such as a quantum dot or multilayered gold/silica nanoparticles. Upconversion luminescence (UCL) has been observed in nanoparticles of compositions such as NaYF4 doped with sensitiser ions such as Yb3+ and activator ions such as Er3+. Magnetomotive optical coherence tomography (MM-OCT) is used to image dynamic magnetic nanoprobes in biological subjects because these probes alter the local optical properties of the tissue.