Biological Applications of Rare-Earth Based Nanoparticles

Abstract

Biomedicine and cell and molecular biology require powerful imaging techniques of the single molecule scale to the whole organism, either for fundamental science or diagnosis. These applications are however often limited by the optical properties of the available probes. Moreover, in cell biology, the measurement of the cell response with spatial and temporal resolution is a central instrumental problem. This has been one of the main motivations for the development of new probes and imaging techniques either for biomolecule labeling or detection of an intracellular signaling species. The weak photostability of genetically encoded probes or organic dyes has motivated the interest for different types of nanoparticles for imaging such as quantum dots, nanodiamonds, dye-doped silica particles, or metallic nanoparticles. One of the most active fields of research in the past decade has thus been the development of rare-earth based nanoparticles, whose optical properties and low cytotoxicity are promising for biological applications. Attractive properties of rare-earth based nanoparticles include high photostability, absence of blinking, extremely narrow emission lines, large Stokes shifts, long lifetimes that can be exploited for retarded detection schemes, and facile functionalization strategies. The use of specific ions in their compositions can be moreover exploited for oxidant detection or for implementing potent contrast agents for magnetic resonance imaging. In this review, we present these different applications of rare-earth nanoparticles for biomolecule detection and imaging in vitro, in living cells or in small animals. We highlight how chemical composition tuning and surface functionalization lead to specific properties, which can be used for different imaging modalities. We discuss their performances for imaging in comparison with other probes and to what extent they could constitute a central tool in the future of molecular and cell biology.

Cerium oxide nanoparticle: a remarkably versatile rare earth nanomaterial for biological applications

“…2 The chemistry of rare earth differs from main group elements and transition metals because of the nature of the 4f orbitals, which are 'buried' inside the atom and are shielded from the atom's environment by the 4d and 5p electrons. 1,2 These orbitals give rare earth unique catalytic, magnetic and electronic properties.…”

Facilitating Translational Nanomedicine via Predictive Safety Assessment

“…31 For example, numerous studies explored the application of these nanomaterials in MRI and showed that they could significantly improve the image contrast. RE-based nanomaterials such as UCNPs often outperform conventional imaging probes in terms of photostability and detection efficiency.…”

“…RE-based nanomaterials such as UCNPs often outperform conventional imaging probes in terms of photostability and detection efficiency. 31 In addition to imaging applications, UCNPs could be applied for photodynamic therapy and cancer treatment. 32 However, the growing application of RE-based nanomaterials could increase the possibility of human exposure and adverse health outcomes.…”

Structural disorder-dependent upconversion in Er3+/Yb3+-doped calcium titanate

“…Rare-earth (RE) doped materials are widely used in optical devices such as sensors, amplifiers, waveguides, solid-state lighting and lasers, as well as in biological applications [1][2][3][4][5]. They are characterized mainly due to their partially filled 4f shells, which results various unique optical features.…”