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

Abstract

Noble metal nanoparticles (NPs) show distinctive plasmonic optical properties and superior photostability, enabling them to serve as photostable multi-coloured optical molecular probes and sensors for real-time in vivo imaging. To effectively study biological functions in vivo , it is essential that the NP probes are biocompatible and can be delivered into living organisms non-invasively. In this study, we have synthesized, purified and characterized stable (non-aggregated) gold (Au) NPs (86.2 ± 10.8 nm). We have developed dark-field single NP plasmonic microscopy and spectroscopy to study their transport into early developing zebrafish embryos (cleavage stage) and their effects on embryonic development in real-time at single NP resolution. We found that single Au NPs (75–97 nm) passively diffused into the embryos via their chorionic pore canals, and stayed inside the embryos throughout their entire development (120 h). The majority of embryos (96 ± 3%) that were chronically incubated with the Au NPs (0–20 pM) for 120 h developed to normal zebrafish, while an insignificant percentage of embryos developed to deformed zebrafish (1 ± 1)% or dead (3 ± 3)%. Interestingly, we did not observe dose-dependent effects of the Au NPs (0–20 pM) on embryonic development. By comparing with our previous studies of smaller Au NPs (11.6 ± 0.9 nm) and similar-sized Ag NPs (95.4 ± 16.0 nm), we found that the larger Au NPs are more biocompatible than the smaller Au NPs, while the similar-sized Ag NPs are much more toxic than Au NPs. This study offers in vivo assays and single NP microscopy and spectroscopy to characterize the biocompatibility and toxicity of single NPs, and new insights into the rational design of more biocompatible plasmonic NP imaging probes.

In situ calibration of position detection in an optical trap for active microrheology in viscous materials

“…The corresponding shear modulus G' ~633 Pa is within an order of magnitude of our measurements. Diffusion constants of cleavage-stage zebrafish embryos of ~6 × 10 −9 cm 2 •s −1 have been measured with gold nanoparticles, corresponding to viscosity η ~4 × 10 −3 Pa•s [49]. Zebrafish whole blood viscosity was found to be ~3.5 × 10 −3 Pa•s [50].…”

Silver nanoparticles induce developmental stage-specific embryonic phenotypes in zebrafish

“…1–2, 19–20, 24, 35–38 However, systematic characterization of the effects of a library of well-design nanomaterials on embryonic development has not yet been carried out to validate the effectiveness of the embryos as in vivo assays. Many studies did not characterize physicochemical properties of individual NPs in vivo in situ in real time.…”

“…1–2, 19–20, 24, 35 However, none of these previous studies permit us to investigate stage-specific abnormalities. In this study, we select vital and representative developmental-stage (cleavage, early-gastrulation, early-segmentation, late-segmentation, and hatching stages) embryos, acutely expose them to the purified and stable Ag NPs (13.1 ± 2.5 nm) for only 2 h, and then characterize their development in egg water over 120 h. This study aims to determine whether Ag NPs can incite stage-dependent abnormalities, understand their stage-dependent toxicity, and identify important embryonic developmental stages for further analysis.…”

Detection, Counting, and Imaging of Single Nanoparticles

“…A follow-up work on Au nanoparticles by the same group discovered that Au nanoparticles exhibited less toxicity than Ag nanoparticles with the same size. 141 …”