In Vivo Quantitative Study of Sized-Dependent Transport and Toxicity of Single Silver Nanoparticles Using Zebrafish Embryos

Abstract

Nanomaterials possess distinctive physicochemical properties (e.g., small sizes, high surface area-to-volume ratios) and promise a wide variety of applications, ranging from design of high quality consumer products to effective disease diagnosis and therapy. These properties can lead to toxic effects, potentially hindering advance in nanotechnology. In this study, we have synthesized and characterized purified and stable (non-aggregation) silver nanoparticles (Ag NPs, 41.6±9.1 nm in average diameters), and utilized early-developing (cleavage-stage) zebrafish embryos (critical aquatic and eco- species) as in vivo model organisms to probe diffusion and toxicity of Ag NPs. We found that single Ag NPs (30–72 nm diameters) passively diffused into the embryos through chorionic pores via random Brownian motion and stayed inside the embryos throughout their entire development (120 hours-post-fertilization, hpf). Dose and size dependent toxic effects of the NPs on embryonic development were observed, showing the possibility of tuning biocompatibility and toxicity of the NPs. At lower concentrations of the NPs (≤ 0.02 nM), 75–91% of embryos developed to normal zebrafish. At the higher concentrations of NPs (≥ 0.20 nM), 100% of embryos became dead. At the concentrations in between (0.02–0.2 nM), embryos developed to various deformed zebrafish. Number and sizes of individual Ag NPs embedded in tissues of normal and deformed zebrafish at 120 hpf were quantitatively analyzed, showing deformed zebrafish with higher number of larger NPs than normal zebrafish, and size-dependent nanotoxicity. By comparing with our previous studies of smaller Ag NPs (11.6±3.5 nm), the results further demonstrate striking size-dependent nanotoxicity that, at the same molar concentration, the larger Ag NPs (41.6±9.1 nm) are more toxic than the smaller Ag NPs (11.6±3.5 nm).

Real-time in vivo imaging of size-dependent transport and toxicity of gold nanoparticles in zebrafish embryos using single nanoparticle plasmonic spectroscopy

“…By comparing with these previous studies of smaller Au NPs and various-sized Ag NPs [11,16,18,19], we found the size-dependent and chemical-dependent biocompatibility and toxicity of the Au and Ag NPs. Notably, our previous studies neither predict nor conclude the effects of larger Au NPs (86.2 + 10.6 nm) on the embryonic development.…”

“…The larger Au NPs cause fewer embryos to become dead than the smaller Au NPs, suggesting that the larger Au NPs (86.2 + 10.8 nm) are more biocompatible (less toxic) than smaller Au NPs (11.6 + 0.9 nm) at the same given doses. By contrast, our previous studies of the effects of purified and stable Ag NPs (11.6 + 3.5, 41.6 + 9.1 and 95.4 + 16.0 nm with similar doses to the Au NPs) on the embryonic development show much higher toxicity of Ag NPs than the Au NPs [11,18,19]. The toxicity of Ag NPs highly depends on their doses and sizes [11,18,19].…”

“…We calculated their molar concentrations by dividing moles of single Au NPs by the solution volume, and characterized rsfs.royalsocietypublishing.org Interface Focus 3: 20120098 them as we described previously [11,16,18,19,35]. Briefly, we calculated the weight of Au (W Au ) generated by the complete reduction of ).…”

Particle Size Dependent Teratogenicity of Silver Nanoparticles in Mice

“…At concentrations ≥0.19 nm, all embryos were deformed (e.g., pericardial edema, tail/spinal cord flexure) and/or died; the effects were concentration-dependent. The authors later repeated the experiment with larger AgNPs (42 nm) and reported similar results [7]: at concentrations ≥0.20 nm, all embryos died; at 0.02 nm, most of the embryos developed normally. At concentrations between 0.02 and 0.2 nm, embryos were deformed.…”

Silver Nanoparticles in the Environment

“…However, different from previous studies that smaller particles were more toxic, the authors found that larger AgNPs (41.6 AE 9.1 nm) produced higher toxic impacts and more severely deformed zebrash than the smaller ones (11.6 AE 3.5 nm) at the same concentration. 114 Chae et al 115 used Japanese medaka (Oryzias latipes) as a model animal to assess the toxic effects of AgNPs. Real time RT-PCR analysis was utilized to monitor the variation of stressrelated gene expression aer exposure to 1 and 25 mg mL…”