Coated up-conversion nanoparticles

Abstract

The invention provides novel biocompatible upconversion nanoparticle (UCNP) that comprises a core of cubic nanocrystals (e.g., comprising α-Na Lna, Lnb Lnc F4) and an epitaxial shell (e.g., formed from CaF2; wherein Lnb is Yb), and related methods of preparation and uses thereof.

What is claimed is: 
     
         1 - 62 . (canceled) 
     
     
         63 . A method of whole-body imaging of an animal, comprising:
 administering to the animal a biocompatible upconversion nanoparticle comprising:
 a core of cubic nanocrystals comprising α-Na (Y, Yb, Tm)F 4 ; and 
 an epitaxial shell formed from CaF 2 , 
   wherein the molar ratio of Tm/(Y+Yb+Tm) is a about 0.5±0.02%, and the molar ratio of Yb/(Y+Yb+Tm) is greater than 30%;   exciting the nanoparticle with a laser a wavelength in the range of about 900 nm to about 1064 nm; and   recording the emission luminescence at a wavelength in the range of about 980 nm to about 800 nm.   
     
     
         64 . The method of  claim 63 , wherein the excitation wavelength is about 980 nm. 
     
     
         65 . The method of  claim 63 , wherein the emission luminescence is about 800 nm. 
     
     
         66 . A method for activating a light sensitive molecule, comprising:
 administering to a cell an upconversion nanoparticle coated with a light sensitive molecule; exciting the nanoparticle with a laser having a wavelength from about 900 nm to about 1064 nm;   causing the particle to emit a luminescence at a wavelength of from about 340 nm to about 380 nm; and   activating the light sensitive molecule.   
     
     
         67 . The method of  claim 66 , wherein the nanoparticle comprises a core of cubic nanocrystals comprising α-Na (Y, Yb, Tm)F 4 ; an epitaxial shell formed from CaF 2 ; and an outer layer of an organic acid which covers the epitaxial shell, wherein the molar ratio of Tm/(Y+Yb+Tm) is a about 0.5±0.02%; and, the molar ratio of Yb/(Y+Yb+Tm) is greater than 30%. 
     
     
         68 . The method of  claim 66 , wherein the excitation wavelength is about 980 nm, and the emission luminescence of the nanoparticle is about 365 nm. 
     
     
         69 . The method of  claim 66 , wherein the light sensitive molecule is activated at a wavelength from about 340 nm to about 380 nm. 
     
     
         70 . The method of  claim 66 , wherein the light sensitive molecule are derivatives of the 2-nitrobenzyl groups and the coumarin moieties and their protected biological active macromolecules.