Controllable synthesis of NaYF4 : Yb,Er upconversion nanophosphors and their application to in vivo imaging of Caenorhabditis elegans

Abstract

β-NaYF4 : Yb,Er upconversion nanoparticles (UCNPs) can emit bright green fluorescence under near-infrared (NIR) light excitation which is safe to the body and can penetrate deeply into tissues. The application of UCNPs in biolabeling and imaging has received great attention recently. In this work, β-NaYF4 : Yb,Er UCNPs with an average size of 35 nm, uniformly spherical shape, and surface modified with amino groups were synthesized by a one-step green solvothermal approach through the use of room-temperature ionic liquids as the reactant, co-solvent and template. The as-prepared UCNPs were introduced into Caenorhabditis elegans (C. elegans) to achieve successful in vivo imaging. We found that longer incubation time, higher UCNP concentration and smaller UCNP size can make the in vivo fluorescence of C. elegans much brighter and more continuous along their body. The worms have no apparent selectivity on ingestion of the UCNPs capped with different capping ligands while having similar size and shape. The next generation of worms did not show fluorescence under excitation. In addition, low toxicity of the nanoparticles was demonstrated by investigating the survival rates of the worms in the presence of the UCNPs. Our work demonstrates the potential application of the UCNPs in studying the biological behavior of organisms, and lays the foundation for further development of the UCNPs in the detection and diagnosis of diseases.

Enhancing the Imaging and Biosafety of Upconversion Nanoparticles through Phosphonate Coating

“…9–13 The use of optical properties together with the high resistance to photobleaching and photochemical degradation, allows lanthanide-doped UCNPs to be considered as promising new bioimaging agents for advanced accomplishments, such as single-molecule tracking, multiplexed labeling and deep tissue imaging. 14–20 While to date no serious toxicity has been observed during the use of UCNPs in organisms such as C. elegans, 2, 21 zebra fish, 22 and rodent studies, 16, 23–25 we are aware of the problems caused by Gd-based MRI agents in renal failure patients where these reagents can lead to nephrogenic systemic fibrosis (NSF). 26, 27 Moreover, there is documentation of the occurrence of an occupational lung disease in RE miners or workers exposed to RE materials ( e.g.…”

Photonen aufkonvertierende Nanopartikel zur optischen Codierung und zum Multiplexing von Zellen, Biomolekülen und Mikrosphären

“…Unmodifizierte UCNPs wurden zunächst dazu verwendet, um ihre Verteilung in Fadenwürmern, [167][168][169] hçheren Tieren [140,156,170] und Pflanzen [171] zu beobachten. Die Vorteile der UCNPs wurden anschließend für die biomedizinische Forschung an ganzen Tieren genutzt, wie kürzlich in einem Übersichtsartikel beschrieben.…”

Photofunctional hybrid silica microspheres covalently functionalized with metalloporphyrins

“…Especially, the triplet energies of porphyrins (typically 12,000-17,000 cm À 1 ) render them suitable chromophores for the sensitization of the relatively low-lying excited state of lanthanide ions such as Yb 3 þ (10,200 cm À 1 ) [24]. The Yb 3 þ ion plays an important role in laser emission because of its very simple f-f energy level structure.…”