Upconverting nanophosphors for bioimaging

Abstract

Upconverting nanoparticles (UCNPs) when excited in the near-infrared (NIR) region display anti-Stokes emission whereby the emitted photon is higher in energy than the excitation energy. The material system achieves that by converting two or more infrared photons into visible photons. The use of the infrared confers benefits to bioimaging because of its deeper penetrating power in biological tissues and the lack of autofluorescence. We demonstrate here sub-10 nm, upconverting rare earth oxide UCNPs synthesized by a combustion method that can be stably suspended in water when amine modified. The amine modified UCNPs show specific surface immobilization onto patterned gold surfaces. Finally, the low toxicity of the UCNPs is verified by testing on the multi-cellular C. elegans nematode.

Preparation and characterization of stable aqueous suspensions of up-converting Er3+/Yb3+-doped LiNbO3 nanocrystals

“…For biological applications, and particularly for imaging, one of the explored solutions relies on up-conversion processes using Yb 3+ and Er 3+ as doping ions [12][13][14][15]. In fact, this mechanism is well characterized in many materials, including LNB:Er 3+ /Yb 3+ bulk crystals [16][17][18][19][20][21].…”

Lanthanide-based nanostructures for optical bioimaging: Small particles with large promise

“…15 -18 It was further shown that the functionalization of Y 2 O 3 :Er 3+ ,Yb 3+ with amine groups allows specifi c surface immobilization, and provides water-dispersibility, biocompatibility, and the ability for bioconjugation. 19 For reliable cancer imaging, Gd 3+ ions are potential co-dopants to introduce magnetic properties, allowing for magnetic resonance imaging (MRI). 20 Aside from doping with Gd 3+ ions, several groups investigated the suitability of Ln 3+ -doped magnetic host materials as multimodal biomarkers that combine excellent optical and magnetic properties, allowing for high spatial resolution imaging via MRI.…”

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.…”