A Four-Color Colloidal Multiplexing Nanoparticle System

Abstract

Any labeling with multicolor markers can be affected by the autofluorescence of biological tissue due to the UV or blue light excitation sources, or the results are affected by fluorescence resonance energy transfer. In this work, we present novel IR-to-vis upconverting nanoparticles of different rare earth metal dopants. With a single excitation source of 980 nm, four different colors of nanocrystals can be spectrally separated under multiplexing conditions. The particles were phase transferred into polar solvents by means of silica encapsulation and were characterized by transmission electron microscopy, X-ray diffraction, and photoluminescence spectroscopy.

Synthesis of β-Phase NaYF4:Yb,Er Upconversion Nanocrystals and Nanorods by Hot-Injection of Small Particles of the α-Phase

“…Upon excitation at 978 nm, the Yb, Er-doped samples display the characteristic two-photon upconversion emission in the green and red spectral region along with some weak emission in the blue caused by the corresponding threephoton process ( Figure 6, -NaYF 4 :Yb,Er particles) [63]. In Figure 7, the upconversion intensities of our samples are compared with the emission of -NaYF 4 :Yb,Er bulk material.…”

Surface modification, functionalization and bioconjugation of colloidal inorganic nanoparticles

“…Then, using this first layer, a polymeric, crosslinked inorganic silica shell is deposited on the particles, which can be further derivatized. Nanoparticles of different materials (Mulvaney et al 2000;Graf et al 2003;Jana et al 2007), in particular noble metals (Au, Liz-Marzán et al 1996;Buining et al 1997;Ag, Hardikar & Matijevic 2000;Han et al 2008), fluorescent quantum dots (CdSe/ZnS, Gerion et al 2001;Nann & Mulvaney 2004;Darbandi et al 2005), phosphorescent (Ehlert et al 2008) and magnetic nanoparticles (e.g. Fe, Ohmori & Matijevic 1993;Co, Kobayashi et al 2003; CoFe 2 O 4 , Wagner et al 2002) and particles of different shapes have been coated with silica shells.…”

Recent advances in the optimization and functionalization of upconversion nanomaterials for in vivo bioapplications

“…The most commonly used emitters are Er 3 þ , Tm 3 þ and Ho 3 þ that have main upconversion emission bands located in the green and red regions, the blue and NIR regions and the green region, respectively ( Figure 1). 16 To date, the most widely investigated upconversion nanosystem is the NaREF 4 nanocrystal, where RE stands for rare earth elements, including Y and all the lanthanides (La to Lu). Because of the low solubility of NaREF 4 nanocrystals in both aqueous and organic solutions, NaREF 4 upconversion nanocrystals are easily synthesized using the coprecipitation method from corresponding precursors to provide the required amount of elements.…”