Because gold nanoparticles (NPs) are resistant to oxidative dissolution and are easily detected, they have been used as stable probes for the behavior of nanomaterials within biological systems. Previous studies provide somewhat limited evidence for bioavailability of Au NPs in food webs. In this presentation, we provide multiple lines of evidence, including orthogonal microspectroscopic techniques, as well as evidence from biological responses that demonstrate Au NPs are bioavailable from soil to a model detritivore (Eisenia fetida). We also present limited evidence that AuNPs may cause adverse effects on earthworm reproduction. Surface functionalization of Au NPs with Mn (II) ions produces for the first time novel Mn-Au NPs positive contrast agents which offer the potential of site-specific magnetic resonance MR T1-weighted molecular imaging capabilities for in vivo and in vitro applications. In vitro MRI measurements made in agarose gel phantoms exhibit high relaxivity (18.26 � 1.04 mmol-1�sec-1). Controlled incubation of nanoparticles with mesenchymal stem cells (MSCs) is used to study cellular uptake of particles. This process appears to be controlled by the size of nanoparticle aggregates in the extracellular solution. The results of this study will be described in detail.

Gold nanoparticles: Bioavailability and bioimaging applications

243rd National Meeting (2012)

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