[Development of Drug Delivery Technology and Nanomedicine by Using Gold Nanoparticles]

Nanomedicine is a new medical field involving the use of nanoparticles. Early examples of biocompatible nanomedicines include liposomes (Doxil^®) and albumin nanoparticles (Abraxane^®), and promising new nanomedicines include nanocarriers such as nanomicelles and nanoemulsions. A new trend towards the use of metal-based nanoparticles, including gold nanoparticles, has led to global clinical trials. These particles exhibit novel properties compared to conventional nanomedicines such as liposomes and albumin nanoparticles. These properties hold promise for nanomedicines, and thus the biodistribution and pharmacokinetics of metal-based nanoparticles should be carefully investigated. This had led to an increasing number of clinical trials investigating metal nanoparticles and inorganic nanoparticles. The present review evaluates multi-functional gold nanoparticles described in recent articles and shows that the unique properties of gold nanoparticles are applicable for not only drug delivery, but also for imaging. The combined therapeutic modality between therapeutics and diagnostics is called "theranostics" and is promising for future personalized cancer therapy. This review also introduces recent research from our laboratory involving the use of various kinds of molecules [polyethylene glycol (PEG), drug/cyclodextrin inclusion complexes, biosimilars and small interfering (siRNAs)] loaded onto and/or conjugated with gold nanoparticles.