Doxorubicin-Conjugated Bimetallic Silver-Gadolinium Nanoalloy for Multimodal MRI-CT-Optical Imaging and pH-Responsive Drug Release.

Monodispersed chitosan-capped bimetallic nanoparticles (BNPs) of AgGd have been synthesized for "cancer theranosis" through environmentally benign microwave-assisted polyol synthesis. In the present article, we report the one-pot synthesis of AgGd BNPs with varied Ag:Gd molar ratios via coreduction of Ag+ and Gd3+ ions. Studies reveal a well-dispersed AgGd BNPs of average size 12 nm and also the presence of face-centered cubic (FCC) Ag and cubic Gd components within the individual crystal. Chitosan (CS) a biopolymer, as a capping agent facilitates the bioconjugation of doxorubicin (Dox), a potential anticancer drug on the surface of BNPs. The Dox was covalently conjugated onto the BNPs through pH-sensitive hydrazone linkage with CS. In vitro study reveals negligible drug release at physiological pH while release rate accelerates in acidic medium. The mutual properties of the host metals in AgGd BNPs at the nanoscale offer concurrent magnetic resonance imaging (MRI) and computed tomography (CT) contrast performances. Moreover, the paramagnetic behavior inherited by Gd in BNPs demonstrates both T1 and T2 contrast ability. BNPs ensures biocompatibility and also express sturdy therapeutic effects in HeLa cells when conjugated with Dox.