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An overview of quantumquantumdotdotsynthesis, applications

and safetyNastassja Lewinski

Department of Bioengineering

nal@rice.edu

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What are Quantum Dots?

II-VI: ZnS, ZnSe, CdSe,

CdTe, CdS, HgS

III-V: GaAs, GaN, InP,

InAs, InGaAs

IV-VI: PbS, PbSe

II

IV V VIIII

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What do Quantum Dots look like?

Control AntiHER2

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Quantum dots

~2 - 6 nm

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How are they made?

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Synthesis Movie

http://www.youtube.com/watch?v=2XfFQKEfCcw&feature=related

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Why do we care?

Medintz et al. Nature Mat., 4, 2005.

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Luminescence

Energy

Ground State

Excited State

Ab

sorp

tion

(exc

ita

tion

)

F

luorescence

(em

iss

ion

)

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Electromagnetic Spectrum

400 nm 700 nm

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Bare CdSe QD Spectra

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CdSe/ZnS Excitation-Emission Matrix

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-(CH-CH-CH2-CH)m-

O

OHO NH

(O-CH2-CH2)n-OCH3

Water solubilization

Silica shelling

Polymaleic anhydride oxide - polyethylene glycol (PMAO-PEG)

HS

O

OH

-[CH2-CH]x-[CH2-CH]y-[CH2-C-CH2-C-CH2-C]z-

COOC4H9COOC2H5

COOH CH3

CONHC8H17

COOH

Amphiphilic triblock polymer

Mercaptoundecanoic acid

O

Si SH

O

3-mercaptopropylmethyldimethoxysilane

(MPS)

O

Si O

O

O

O

nO

Si NH2

O2-[methoxy(polyethleneoxy)propyl]-

trimethoxysilane (PEOS)

3-aminopropylmethyldimethoxysilane

(APS)

Polymer wrapping

Ligand exchange

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Particle Aggregation

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How are they used?

Michalet et al. Science, 307, 2005

Gao et al. Nat.Biotech., 22, 2004Green, Angew. Chem., 43, 2004

Sapsford et al. Sensors, 6, 2006

Parungo et al. JTCS, 129, 2005

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Tumor Tissue Margin Detection

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NIR Optical Window

Absorptioncoefficient(cm

-1)

Wavelength (nm)

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Toxicity Concerns

HS

O

OH

-(CH-CH-CH2-CH)m-

O

OH

O NH

(O-CH2-CH2)n-OCH3

Low pH - lysosomes

Oxidation - peroxisomes

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Lewinski et al. Small, 4, 2008

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Daphnia magna

4x Brightfield

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Qdot Localization

10x Brightfield

10x Fluorescence

(DAPI excitation filter)

Rectum

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