Ultra-small Albumin Templated Gd/Ru Composite Nanodots for In Vivo Dual modal MR/Thermal Imaging Guided Photothermal Therapy.

Multifunctional theranostic nanoagents which realize precise diagnosis and treatment of tumors are attracting increasing interests in recent years. However, efficient and controlled synthesis of ultra-small noble metal nanoagents remains a challenge. Here, monodisperse Gd/Ru@BSA nanodots (GRBNDs) are successfully fabricated via a totally "green", "one-pot" protocol for in situ reduction of Ru(III) and biomineralization of Gd(III) in the presence of albumin. The as-prepared nanoagent possesses the features of being ultra small in size (≈6.7 nm), having strong colloidal stability, and thermal stability as well as high photothermal conversion efficiency (η = 50.7%). As expected, the GRBNDs achieve a significant efficacy of anticancer therapy under LASER activation both in vitro and in vivo. It also exhibits superior T1 -weighted magnetic resonance (MR) imaging ability due to its high longitudinal relaxivity value (r1 = 10.98 × 10-3 m-1 s-1 ). Moreover, it is demonstrated to be renal clearable with negligible systemic toxicity. This work highlights a straightforward and repeatable approach for synthesizing highly effective and multifunctional noble metal nanoagent of great clinical promising for cancer theranostics.