An x-ray computed tomography imaging agent based on long-circulating bismuth sulphide nanoparticles. Nat Mater

Harvard University, Cambridge, Massachusetts, United States
Nature Materials (Impact Factor: 36.5). 02/2006; 5(2):118-22. DOI: 10.1038/nmat1571
Source: PubMed


Nanomaterials have become increasingly important in the development of new molecular probes for in vivo imaging, both experimentally and clinically. Nanoparticulate imaging probes have included semiconductor quantum dots, magnetic and magnetofluorescent nanoparticles, gold nanoparticles and nanoshells, among others. However, the use of nanomaterials for one of the most common imaging techniques, computed tomography (CT), has remained unexplored. Current CT contrast agents are based on small iodinated molecules. They are effective in absorbing X-rays, but non-specific distribution and rapid pharmacokinetics have rather limited their microvascular and targeting performance. Here we propose the use of a polymer-coated Bi(2)S(3) nanoparticle preparation as an injectable CT imaging agent. This preparation demonstrates excellent stability at high concentrations (0.25 M Bi(3+)), high X-ray absorption (fivefold better than iodine), very long circulation times (>2 h) in vivo and an efficacy/safety profile comparable to or better than iodinated imaging agents. We show the utility of these polymer-coated Bi(2)S(3) nanoparticles for enhanced in vivo imaging of the vasculature, the liver and lymph nodes in mice. These nanoparticles and their bioconjugates are expected to become an important adjunct to in vivo imaging of molecular targets and pathological conditions.

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Available from: Jan Grimm, Sep 26, 2014
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    • "Despite the above-mentioned advantages of metal-containing nanoparticles over molecular agents, only a few nanoparticle CT contrast agents have been studied thus far [12, 14–20]. These include gold (Au) nanoparticles [12, 14– 16], Gd(IO 3 ) 3 nanoparticles [17], Gd 2 O 3 nanoparticles [19] [20], and tantalum oxide nanoparticles [21], and bismuth sulphide nanoparticles [22]. It is important to note that gold, tantalum, and bismuth have much larger linear x-ray attenuation coefficients than iodine, as does Gd [13], (see footnote 7). "
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    • "Several nanoparticulated CT contrast agents have been reported based on iodine functionalized polymers [3], gold nanoparticles [4], core–shell iron oxide/tantalum oxide nanoparticles [5] and iron-platinum alloy nanoparticles [6]. Nanoparticulated CT contrasts bearing bismuth, in particular bismuth sulphide nanodots (2–3 nm) [8] [9] [10] [11], have obtained special attention due to a combination of low price, low toxicity and a high x-ray attenuation coefficient [2] [7]. This material has been successfully prepared in large quantities and targeted to contrast breast cancer [10]. "
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    • "However, to develop AuNP-based CT contrast agents with desirable properties, such as good biocompatibility, easy and controllable surface modification, sharp contrast, and prolonged imaging time [23-25], multiple complicated steps are generally required. Recent studies have shown that proper modification of AuNPs can extend their circulation time in cardiovascular diseases by decreasing the rapid uptake and clearance by the reticuloendothelial system (RES) [19,26-28]. One promising and efficient technique to achieve this goal is to modify AuNPs with polyethylene glycol (PEG) molecules [29,30]. "
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