Journal
ACS NANO
Volume 9, Issue 3, Pages 3293-3306Publisher
AMER CHEMICAL SOC
DOI: 10.1021/acsnano.5b00439
Keywords
nanotoxicity; surface coating; fluorescence quenching; functionalization; lysosome; cell uptake
Categories
Funding
- National Institute of Environmental Health Sciences [R01 ES016746]
- National Science Foundation
- Environmental Protection Agency [DBI 0830117, 1266377]
- JCCC [P30 CA016042]
Ask authors/readers for more resources
Upconversion nanoparticles (UCNPs), which are generated by doping with rare earth (RE) metals, are increasingly used for bioimaging because of the advantages they hold over conventional fluorophores. However, because pristine RE nanoparticles (NPs) are unstable in acidic physiological fluids (e.g., lysosomes), leading to intracellular phosphate complexation with the possibility of lysosomal injury, it is important to ensure that UCNPs are safely designed. In this study, we used commercially available NaYF4:Er/Yb UCNPs to study their stability in lysosomes and simulated lysosomal fluid. We demonstrate that phosphate complexation leads to REPO4 deposition on the particle surfaces and morphological transformation. This leads to a decline in upconversion fluorescence efficiency as well as inducing pro-inflammatory effects at the cellular level and in the intact lung. In order to preserve the imaging properties of the UCNPs as well as improve their safety, we experimented with a series of phosphonate chemical moieties to passivate particle surfaces through the strong coordination of the organophosphates with RE atoms. Particle screening and physicochemical characterization revealed that ethylenediamine tetra(methylenephosphonic acid) (EDTMP) surface coating provides the most stable UCNPs, which maintain their imaging intensity and do not induce pro-inflammatory effects in vitro and in vivo. In summary, phosphonate coating presents a safer design method that preserves and improves the bioimaging properties of UCNPs, thereby enhancing their biological use.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available