Zinc Oxide Quantum Dots stabilized by polyethers as...
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In this study novel organometallic pathway was developed in order to prepare low dispersed ZnO nanoparticles. Capping technique was used to stabilize nanocrystals. Polyethers were chosen as protecting ligands due to possibility to solubilize obtained ZnO quantum dots PETH shell allows for ZnO QDs transfer from organic solvent into water medium. Size of the ZnO@PETH were determined by HRTEM and DLS analysis. All obtained QDs have very similar photoluminescent properties and relatively high quantum yield. Prepared ZnO@PETH were tested as bio labels in the CCD cell line showing potential of stabile and soluble ZnO QDs in the medical techniques. Zinc Oxide Quantum Dots stabilized by polyethers as potential cell labeling agents Katarzyna Wójcik a , Małgorzata Wolska b , Anna Wojewódzka b , Kamil Jastrzębski c , Łukasz Sadowski c , Janusz Lewiński a,b a. Institute of Physical Chemistry PAS, ul. Kasprzaka 44/52, 01-224 Warsaw, b. Warsaw University of Technology, ul. Noakowskiego 3, 00-664 Warsaw, c. The International Institute of Molecular and Cell Biology, ul. Trojdena 4, 02-109 Warsaw Acknowledgements Introduction Nanomaterials except the extremely small size possess unique physical and chemical properties having the potential for wide- ranging industrial, biomedical, and electronic applications. Photoluminescent semiconductor nanocrystals called Quantum Dots (QDs) are novel class of inorganic nanomaterials which are promising candidates for labeling agents in cellular imaging enable to serve as novel tools and techniques that have not existed previously in biomedical research. Zinc oxide nanoparticles attract attention as ideal candidates for Cd-based fluorescent replacement since they are nontoxic possessing at the same time good optical properties, high quantum yield, broad absorption spectrum and narrow emission spectrum. • J. Lewiński et al. Angewandte Chemie International Edition, 2008, 47(3), 573 • Lewiński et al. patent application P-385427 nano-ZnO Methodology of the synthesis of ZnO QDs R' OH O R 2 Zn R' O H O Zn - R 2+ + R' - alkyl group Reaction between alkylzink and carboxyl ligand Oxo-clusters air water Can you imagine something up to 10 000 times smaller than a human hair? If yes, you just created a nanomaterial. Quantum dots (QDs) have the unique ability to emit light representing the entire rainbow of colors from the same elemental material based solely on the size or surface defects of the particles. Their optical properties can be customized as function of shape, size and composition. Quantum dots ZnO QDs PROPERTIES narrow light emmision spectrum broad light absorption spectrum bright luminescence in different colours size-dependent spectrum properties long-term photostability The capping technique based on direct binding of protective ligand on the nanoparticle surface can be applied in order to stabilize the nanomaterial. Quantum dots coated by ligands are build similar like earth Results ZnO@PETH Synhesis and solubilization A shell formed by ligand layer can change the properties of nanoparticle. Especially we can play with the solubility using ligands with hydrophilic groups. . In this study an original method for the synthesis of well-defined nanoparticulate forms of ZnO was developed. Alkylzinc complexes RZnL (L = ligand) stabilized by various polyethers were transformed under exposure of air and water into monodispersed and ultrasmall ZnO forms. All obtained ZnO QDs (ZnO@PETH) were soluble in DMSO and aqueous environment. ZnO@PETH with their unique properties like luminescence, high quantum yield, solubility and long term stability were evaluated in the imaging of CCD cells showing a great potential of QDs as specific biological labels. 300 400 500 600 700 800 0,0 0,2 0,4 0,6 0,8 1,0 absorbance excitation emission Normalized absorbance/fluorescence Wavelength [nm] ZnO@PETH Photoluminescence This method allows for the synthesis of well define and stable quantum dots with strong luminescent properties in the organic solvents like DMSO. Obtained materials were characterized by HRTEM microscopy. The data indicate the formation of quantum dots with low polydispersity and size around 5 nm. Hydrodynamic diameter with value 15 nm was defined using DLS analysis. ZnO@PETH Size and morphology air water Synthesized ZnO nanoparticles were coated by polyethers (PETH) resulting in formation of monodispersed, ultrasmall ZnO NPs (ZnO@PETH), soluble in DMSO and aquatic media. Polyethers (PETH) used: Polyether (PETH) + ZnEt 2 All three ligands give very similar results ZnO@PETH as biolabels -imaging results Obtained ZnO QDs stabilized by polyethers (ZnO@PETH) were tested as biolabels in the imaging of CCD cells using confocal microscopy. The best results gave nanoparticles coated by methoxyacetic acid. The QDs were selectively located in the mitochondria of the cell after 3 h which can be observed as a red colour in the picture. In the control sample no luminescence was present. The cells were in total treated with the QDs for 24h and no toxic effect of zinc oxide was observed in used concentration. Conclusion Financial support from European Union 7.FP under grant REGPOT-CT-2011- 285949-NOBLESSE is gratefully acknowledged Idea of biolabeling with the use of quantum dots HRTEM In the presence of O 2 and H 2 O organometallic precursors transform into stable ZnO nanoparticles. Direct exposure on air and moisture leads to formation of ZnO QDs coated by organic ligands. Control sample ZnO@PETH O O O O O CH 3 CH 3 ZnO O OH OH ZnO O OH O O O C OH O O O O OH O Methoxyacetic acid 2-(2-methoxyethoxy)acetic acid 2-[2-(2-methoxyethoxy)ethoxy)acetic acid air, water
Transcript of Zinc Oxide Quantum Dots stabilized by polyethers as...
In this study novel organometallic pathway was developed in order to prepare low dispersed ZnO
nanoparticles. Capping technique was used to stabilize nanocrystals. Polyethers were chosen as protecting ligands due to
possibility to solubilize obtained ZnO quantum dots PETH shell allows for ZnO QDs transfer from organic
solvent into water medium. Size of the ZnO@PETH were determined by HRTEM
and DLS analysis. All obtained QDs have very similar photoluminescent
properties and relatively high quantum yield. Prepared ZnO@PETH were tested as bio labels in the
CCD cell line showing potential of stabile and soluble ZnO QDs in the medical techniques.
Zinc Oxide Quantum Dots stabilized by polyethers as potential cell labeling agents
Katarzyna Wójcika, Małgorzata Wolskab, Anna Wojewódzkab, Kamil Jastrzębskic, Łukasz Sadowskic, Janusz Lewińskia,b
a. Institute of Physical Chemistry PAS, ul. Kasprzaka 44/52, 01-224 Warsaw, b. Warsaw University of Technology, ul. Noakowskiego 3, 00-664 Warsaw,
c. The International Institute of Molecular and Cell Biology, ul. Trojdena 4, 02-109 Warsaw
Acknowledgements
Introduction Nanomaterials except the extremely small size possess unique physical and chemical properties having the potential for wide-ranging industrial, biomedical, and electronic applications. Photoluminescent semiconductor nanocrystals called Quantum Dots (QDs) are novel class of inorganic nanomaterials which are promising candidates for labeling agents in cellular imaging enable to serve as novel tools and techniques that have not existed previously in biomedical research. Zinc oxide nanoparticles attract attention as ideal candidates for Cd-based fluorescent replacement since they are nontoxic possessing at the same time good optical properties, high quantum yield, broad absorption spectrum and narrow emission spectrum.
• J. Lewiński et al. Angewandte Chemie International Edition, 2008, 47(3), 573 • Lewiński et al. patent application P-385427
nano-ZnO
Methodology of the synthesis of ZnO QDs
R'OH
O
R2Zn R'
OH
O
Zn- R
2+
+
R' - alkyl group
Reaction between alkylzink and carboxyl ligand
Oxo-clusters
air water
Can you imagine something up to 10 000 times smaller than a human hair?
If yes, you just created a nanomaterial.
Quantum dots (QDs) have the unique ability to emit light representing the entire rainbow of colors from the same elemental material based solely on the size or surface defects of the particles. Their optical properties can be customized as function of shape, size and composition.
Quantum dots
ZnO QDs PROPERTIES narrow light emmision spectrum broad light absorption spectrum
bright luminescence in different colours size-dependent spectrum properties
long-term photostability
The capping technique based on direct binding of protective ligand on the nanoparticle surface can be applied in order to stabilize the nanomaterial.
Quantum dots coated by ligands are build similar like earth
Results ZnO@PETH
Synhesis and solubilization
A shell formed by ligand layer can change the properties of nanoparticle. Especially we can play with the solubility using ligands with hydrophilic groups. .
In this study an original method for the synthesis of well-defined nanoparticulate forms of ZnO was developed. Alkylzinc complexes RZnL (L = ligand) stabilized by various polyethers were transformed under exposure of air and water into monodispersed and ultrasmall ZnO forms. All obtained ZnO QDs (ZnO@PETH) were soluble in DMSO and aqueous environment. ZnO@PETH with their unique properties like luminescence, high quantum yield, solubility and long term stability were evaluated in the imaging of CCD cells showing a great potential of QDs as specific biological labels.
300 400 500 600 700 800
0,0
0,2
0,4
0,6
0,8
1,0
absorbance
excitation
emission
No
rma
lize
d a
bso
rba
nce
/flu
ore
sce
nce
Wavelength [nm]
ZnO@PETH Photoluminescence
This method allows for the synthesis of well define and stable quantum dots with strong luminescent properties in the organic solvents like DMSO.
Obtained materials were characterized by HRTEM microscopy. The data indicate the formation of quantum dots with low polydispersity and size around 5 nm. Hydrodynamic diameter with value 15 nm was defined using DLS analysis.
ZnO@PETH Size and morphology
air water
Synthesized ZnO nanoparticles were coated by polyethers (PETH) resulting in formation of
monodispersed, ultrasmall ZnO NPs (ZnO@PETH), soluble in DMSO and aquatic media.
Polyethers (PETH) used:
Polyether (PETH)
+ ZnEt2
All three ligands give very similar results
ZnO@PETH as biolabels -imaging results
Obtained ZnO QDs stabilized by polyethers (ZnO@PETH) were tested as biolabels in the imaging of CCD cells using confocal microscopy. The best results gave nanoparticles coated by methoxyacetic acid. The QDs were selectively located in the mitochondria of the cell after 3 h which can be observed as a red colour in the picture. In the control sample no luminescence was present. The cells were in total treated with the QDs for 24h and no toxic effect of zinc oxide was observed in used concentration.
Conclusion
Financial support from European Union 7.FP under grant
REGPOT-CT-2011- 285949-NOBLESSE is gratefully acknowledged
Idea of biolabeling with the use of
quantum dots
HRTEM
In the presence of O2 and H2O organometallic precursors transform into stable ZnO nanoparticles. Direct exposure on air and moisture leads to formation of ZnO QDs coated by organic ligands.
Control sample ZnO@PETH
OO
O
O
O CH3
CH3
ZnO
OOH
OH
ZnO
OOH
O
OO C
OH
O
OO
OOH
O
Methoxyacetic acid
2-(2-methoxyethoxy)acetic acid
2-[2-(2-methoxyethoxy)ethoxy)acetic acid
air, water
