Background: Nanoclusters are made of a few to tens of atoms with a size below 2 nm.
Compared with nanoparticles, they exhibited excellent properties, such as tunable fluorescence,
ease of conjugation, high quantum yield and biocompatibility, which are highly desired in the development
of cancer nanotheranostics. Hence, the metallic nanoclusters have emerged as a newcomer
in cancer nanomedicines. This review aims to summarize recently developed approaches to
preparing metallic nanoclusters, highlight their applications in cancer theranostics, and provide a
brief outlook for the future developments of nanoclusters in nanomedicine.
Method: We carried out a thorough literature search using online databases. The search was focused
on a centered question. Irrelevant articles were excluded after further examination and directly
relevant articles were included. The relevant articles were classified by the subjects and the
information from these articles was synthesized.
Results: One hundred and forty-three articles were included in this review. About eighty articles
outlined the development in the synthetic methods of nanoclusters. The synthesis approaches include
chemical reduction, photoreduction and so on. The progress in the application of gold and
silver nanoclusters to cancer theranostics was described in fifteen and eight articles, respectively.
The rest articles were about the advancements in the use of other metal nanoclusters and nanocluster
nanocomposites as cancer theranostic agents.
Conclusion: This review summarizes the synthesis and use of metallic nanoclusters or their nanocomposites
as cancer theranostic agents. It confirms their importance, advantages and potentials in
serving as a new generation of cancer theranostics in clinics.