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 Ln a , Ln b Ln c F 4 ) and an epitaxial shell (e.g., formed from CaF 2 ; wherein Ln b is Yb), and related methods of preparation and uses thereof.

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 50%;
 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 biocompatible upconversion nanoparticle further comprises an outer layer of an organic acid which covers the epitaxial shell, wherein the organic acid is selected from the group consisting of citric acid, hyaluronic acid and polyacrylic acid. 
     
     
         65 . The method of  claim 64 , wherein the organic acid is conjugated to an amine. 
     
     
         66 . The method of  claim 65 , wherein the amine can be conjugated to amine reactive functional groups selected from N-hydroxysulfosuccinimide (NHS) or aldehyde derivatives. 
     
     
         67 . The method of  claim 66 , wherein the NHS coupled fluorescent moiety is selected from the group consisting of NHS-flourescein, NHS-caged fluorescein and NHS-Rodamine, NHS-Cy3.5, NHS-Cy 5.5. 
     
     
         68 . The method of  claim 65 , wherein the amine is conjugated to an antibody. 
     
     
         69 . The method of  claim 63 , wherein the excitation wavelength is about 980 nm. 
     
     
         70 . The method of  claim 69 , wherein the emission luminescence is about 800 nm. 
     
     
         71 . A method for activating a light sensitive molecule, comprising:
 administering to a cell an upconversion nanoparticle coated with a light sensitive molecule comprising a group selected from 2-nitrobenzyl and coumarin;   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,   
       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 50%. 
     
     
         72 . The method of  claim 71 , wherein the excitation wavelength is about 980 nm, and the emission luminescence of the nanoparticle is about 365 nm. 
     
     
         73 . The method of  claim 71 , wherein the light sensitive molecule is activated at a wavelength from about 340 nm to about 380 nm.