Gold-silver alloy nanoshells: a new candidate for nanotherapeutics and diagnostics

Abstract

We have developed novel gold-silver alloy nanoshells as magnetic resonance imaging (MRI) dual T1 (positive) and T2 (negative) contrast agents as an alternative to typical gadolinium (Gd)-based contrast agents. Specifically, we have doped iron oxide nanoparticles with Gd ions and sequestered the ions within the core by coating the nanoparticles with an alloy of gold and silver. Thus, these nanoparticles are very innovative and have the potential to overcome toxicities related to renal clearance of contrast agents such as nephrogenic systemic fibrosis. The morphology of the attained nanoparticles was characterized by XRD which demonstrated the successful incorporation of Gd(III) ions into the structure of the magnetite, with no major alterations of the spinel structure, as well as the growth of the gold-silver alloy shells. This was supported by TEM, ICP-AES, and SEM/EDS data. The nanoshells showed a saturation magnetization of 38 emu/g because of the presence of Gd ions within the crystalline structure with r1 and r2 values of 0.0119 and 0.9229 mL mg-1 s-1, respectively (Au:Ag alloy = 1:1). T1- and T2-weighted images of the nanoshells showed that these agents can both increase the surrounding water proton signals in the T1-weighted image and reduce the signal in T2-weighted images. The as-synthesized nanoparticles exhibited strong absorption in the range of 600-800 nm, their optical properties being strongly dependent upon the thickness of the gold-silver alloy shell. Thus, these nanoshells have the potential to be utilized for tumor cell ablation because of their absorption as well as an imaging agent.

Metal nanoparticle‐hydrogel nanocomposites for biomedical applications – An atmospheric pressure plasma synthesis approach

“…To the best of our knowledge, none of the previous studies have yet explored the one step AMP synthesis of metal NPs/hydrogel biocomposites. The idea is interesting as such material system would possess multi‐functionality that can be used for various applications in the biomedical field, such as anti‐microbial, drug delivery, cancer theranostics, biosensing, etc.…”

Antitumor Activity of Alloy and Core-Shell-Type Bimetallic AgAu Nanoparticles

“…Among the different types of nanoparticles, metal nanoparticles including gold and silver have widespread use across the biomedical sciences [3, 4]. Nanoparticles (NPs) based on noble metals remain promising anticancer agents capable of enhancing existing surgery and chemotherapeutic-based approaches in cancer treatment.…”

Chloroplasts-mediated biosynthesis of nanoscale Au-Ag alloy for 2-butanone assay based on electrochemical sensor

“…Five characteristic peaks (111), (200), (220), (311), and (222) confirmed that the Au-Ag alloy was in the fcc structure [13,30]. The peak corresponding to the {200} plane was more intense than the other planes, suggesting that the {200} plane was the predominant orientation, which demonstrated that the nanoscale Au-Ag alloys are high crystalline [7,31]. …”