Chapter 2 - Nanomaterials for bioimaging studies

Abstract

Novelly designed bioimaging of nanomaterials helps us for greater perception of biological actions at the molecular level since the human body and the living cells are the most complex systems due to its variation in metabolism and diversity in its organic composition. Currently, nanomaterials for in vivo imaging are preferred for various bioapplications such as diagnostics, therapeutics, and development of theranostic tools (coupled therapeutic and diagnostic tools). Recently, nanoparticulate materials were applied in biological imaging and include dye-loaded fluorescent silica nanoparticles (SiNPs) for both in vitro and in vivo noninvasive fluorescent imaging. Multifunctional inorganic nanoparticles are in use for cancer tumor imaging and thermal therapy. Lanthanide-doped upconverting nanoparticles (UCNPs) are used as imaging contrast reagents, image-based drug delivery platforms, and phototherapeutic reagents. SiNPs are highly efficient, have high hydrophilicity and low toxicity, and exhibit excellent biocompatibility and optical transparency. Because of these properties, SiNPs were considered as ideal substrates for the construction of fluorescent probes, which were used for the efficient imaging of live cells and small animals. Multifunctional inorganic nanoparticles are of broad range, classified as metal-based (Ag, Au, Pd, Pt); magnetic (iron oxides); quantum dot-based nanostructures (CdTe, CdSe); near-infrared (NIR)-absorbing carbon nanoparticles (carbon and graphene nanotubes); and upconversion composite nanoparticles (NaGdF4:Yb:Er). Utilization of multifunctional inorganic nanoparticles aids in diagnostics, competently treating the diseased tissue and therapeutics combined with an imaging tool in a single nanostructure. Lanthanide-doped upconverting nanoparticles (UCNPs) convert low-energy NIR photons into high-energy UV or visible emissions utilizing multiphoton upconversion processes that have various applications in bioimaging and biomedicine.