Imaging gold nanoparticles in mouse liver by laser ablation inductively coupled plasma mass spectrometry.

Imaging the size distribution of metal nanoparticles (NPs) in a tissue has important implications in terms of evaluating NP toxicity. Microscopy techniques used to image tissue NPs are limited by complicated sample preparation or poor resolution. In this study, we developed a laser ablation (LA) system coupled to single-particle inductively coupled plasma mass spectrometry (SP-ICP-MS) for quantitative imaging of gold (G)NPs in tissue samples. In this system, GNPs were ablated but did not disintegrate and integrate under optimised operation conditions, which were verified by characterising LA particles by scanning electron microscopy. The feasibility of imaging size distributions in tissue was validated using reference GNPs 60 and 80 nm in size on matrix-matched kidney. A transport efficiency of 6.07% was obtained by LA-SP-ICP-MS under optimal conditions. We used this system to image 80-nm GNPs in mouse liver and the size distribution thus obtained was in accordance with that determined by nebuliser SP-ICP-MS. The images revealed that 80-nm GNPs mainly accumulate in the liver and did not obviously aggregate. Our results demonstrate that LA-SP-ICP-MS is an effective tool for evaluating the size distribution of metal NPs in tissue.