Gold nanoparticles (AuNPs) have undergone significant
research
for their use in the treatment of cancer. Numerous researchers have
established their potent antitumor properties, which have greatly
impacted the treatment of cancer. AuNPs have been used in four primary
anticancer treatment modalities, namely radiation, photothermal therapy,
photodynamic therapy, and chemotherapy. However, the ability of AuNPs
to destroy cancer is lacking and can even harm healthy cells without
the right direction to transport them to the tumor microenvironment.
Consequently, a suitable targeting technique is needed. Based on the
distinct features of the human tumor microenvironment, this review
discusses four different targeting strategies that target the four
key features of the tumor microenvironment, including abnormal vasculature,
overexpression of specific receptors, an acidic microenvironment,
and a hypoxic microenvironment, to direct surface-functionalized AuNPs
to the tumor microenvironment and increase antitumor efficacies. In
addition, some current completed or ongoing clinical trials of AuNPs
will also be discussed below to further reinforce the concept of using
AuNPs in anticancer therapy.