title: microPET-based biodistribution of quantum dots in living mice.
abstract: This study evaluates the quantitative biodistribution of commercially available CdSe quantum dots (QD) in mice.
  
  
  METHODS
  (64)Cu-Labeled 800- or 525-nm emission wavelength QD (21- or 12-nm diameter), with or without 2,000 MW (molecular weight) polyethylene glycol (PEG), were injected intravenously into mice (5.55 MBq/25 pmol QD) and studied using well counting or by serial microPET and region-of-interest analysis.
  
  
  RESULTS
  Both methods show rapid uptake by the liver (27.4-38.9 %ID/g) (%ID/g is percentage injected dose per gram tissue) and spleen (8.0-12.4 %ID/g). Size has no influence on biodistribution within the range tested here. Pegylated QD have slightly slower uptake into liver and spleen (6 vs. 2 min) and show additional low-level bone uptake (6.5-6.9 %ID/g). No evidence of clearance from these organs was observed.
  
  
  CONCLUSIONS
  Rapid reticuloendothelial system clearance of QD will require modification of QD for optimal utility in imaging living subjects. Formal quantitative biodistribution/imaging studies will be helpful in studying many types of nanoparticles, including quantum dots.
authors: Departments of Radiology and Bioengineering, Bio-X Program, Molecular Imaging Program at Stanford (MIPS), Stanford University, East 150 Clark Center, Palo Alto, CA 94305, USA.
authors: Meike L
authors: ML
authors: Schipper
authors: Zhen
authors: Z
authors: Cheng
authors: Sheen-Woo
authors: SW
authors: Lee
authors: Laurent A
authors: LA
authors: Bentolila
authors: Gopal
authors: G
authors: Iyer
authors: Jianghong
authors: J
authors: Rao
authors: Xiaoyuan
authors: X
authors: Chen
authors: Anna M
authors: AM
authors: Wu
authors: Shimon
authors: S
authors: Weiss
authors: Sanjiv S
authors: SS
authors: Gambhir
mesh_terms: D000818:Animals; D001842:Bone and Bones / Q000378:metabolism; D019187:Cadmium Compounds / Q000737:chemistry / Q000493:pharmacokinetics*; D003301:Copper Radioisotopes; D008099:Liver / Q000378:metabolism; D051379:Mice; D008819:Mice, Nude; D011092:Polyethylene Glycols / Q000737:chemistry; D049268:Positron-Emission Tomography / Q000379:methods; D045663:Quantum Dots; D018036:Selenium Compounds / Q000737:chemistry / Q000493:pharmacokinetics*; D013154:Spleen / Q000378:metabolism; D014018:Tissue Distribution; D017967:Zinc Compounds / Q000737:chemistry / Q000493:pharmacokinetics
chemical_list: D019187:Cadmium Compounds; D003301:Copper Radioisotopes; D018036:Selenium Compounds; D017967:Zinc Compounds; D011092:Polyethylene Glycols; C058667:cadmium selenide; C044696:zinc selenide
references: Biosens Bioelectron. 2006 Apr 15;21(10):1859-66
references: 16495043
references: Proc Natl Acad Sci U S A. 2006 Apr 4;103(14):5567-72
references: 16567637
references: Nano Lett. 2006 Apr;6(4):669-76
references: 16608262
references: Phys Med Biol. 2006 Aug 7;51(15):3733-46
references: 16861777
references: J Pharmacol Exp Ther. 2000 Jun;293(3):996-1001
references: 10869403
references: J Pharmacol Exp Ther. 2001 Aug;298(2):607-12
references: 11454922
references: Crit Rev Ther Drug Carrier Syst. 2001;18(6):551-66
references: 11789675
references: Proc Natl Acad Sci U S A. 2002 Oct 1;99(20):12617-21
references: 12235356
references: Biosci Rep. 2002 Apr;22(2):225-50
references: 12428902
references: Eur J Nucl Med Mol Imaging. 2003 May;30(5):737-47
references: 12536244
references: Prog Lipid Res. 2003 Nov;42(6):463-78
references: 14559067
references: Mol Imaging. 2003 Jul;2(3):131-7
references: 14649056
references: Nat Biotechnol. 2006 Mar;24(3):339-43
references: 16501578
references: J Am Chem Soc. 2006 Mar 1;128(8):2526-7
references: 16492023
references: Ann Surg Oncol. 2006 Mar;13(3):386-96
references: 16485157
references: Int J Pharm. 2006 Jan 3;307(1):93-102
references: 16303268
references: J Nucl Med. 2005 Nov;46(11):1851-7
references: 16269599
references: J Am Chem Soc. 2005 Aug 17;127(32):11364-71
references: 16089466
references: Nat Med. 2005 Jun;11(6):678-82
references: 15880117
references: J Thorac Cardiovasc Surg. 2005 Apr;129(4):844-50
references: 15821653
references: Curr Opin Biotechnol. 2005 Feb;16(1):63-72
references: 15722017
references: Science. 2005 Jan 28;307(5709):538-44
references: 15681376
references: Nat Biotechnol. 2004 Aug;22(8):969-76
references: 15258594
references: Bioconjug Chem. 2004 Jan-Feb;15(1):79-86
references: 14733586