Tuyển tập các báo cáo nghiên cứu về hóa học được đăng trên tạp chí hóa hoc quốc tế đề tài : Gold-silver alloy nanoshells: a new candidate for nanotherapeutics and diagnostics | Gheorghe et al. Nanoscale Research Letters 2011 6 554 http content 6 1 554 o Nanoscale Research Letters a SpringerOpen Journal NANO EXPRESS Open Access Gold-silver alloy nanoshells a new candidate for nanotherapeutics and diagnostics Dana E Gheorghe1 Lili Cui1 Christof Karmonik2 Audrius Brazdeikis3 Jose M Penaloza1 Joseph K Young4 Rebekah A Drezek4 5 and Malavosklish Bikram1 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 and 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 .
