18 - Gold nanoparticles in cancer theranostics

Abstract

Removal of cancer tissues does not always lead to disease cure due to lack of early detection, poor prognosis, and limited therapeutic options. The use of nanoparticles (NPs) as detectors has been widespread in recent years for cancer cell detection. Cancer diagnosis and therapy is expected to leap forward in the future with the development of NPs. Gold NPs (AuNPs) exhibit favorable physical properties and tailored functionalities, which provide the foundation for developing cancer theranostics. Cancer imaging techniques can use AuNPs in surface plasma resonance (SPR) as excellent imaging probes that are adaptable by changing shape, size, and composition. AuNPs are also used to detect target biomolecules and their accumulation, while functionalized AuNPs are employed for early stage detection in vitro and in vivo. Nanoporous Au and hollow NPs are two other potent candidates for surface-enhanced Raman scattering (SERS) substrates that are highly active, biocompatible, reusable, and stable. Besides imaging cells, AuNPs are also used for in vivo CT scans and decorated AuNPs have transformed anatomically based cancer diagnosis with molecular imaging. AuNPs have also shown good results in photodynamic (PDT) and photothermal therapy (PTT) along with delivery of drugs. High atomic number and the nontoxic nature of AuNPs have made them suitable candidates as radiosensitizers, with their usages being dependent on factors such as surface coating, concentration, shape, size, and cell types. This chapter reviews the favorable physiochemical properties of AuNPs, therapeutic strategies employed, and their design for early detection and local treatment in using AuNPs as theranostics in oncology.