An overview of quantum dot synthesis, applications and safety

1
An overview of quantum dot synthesis,
applications and safety

• Nastassja Lewinski
• Department of Bioengineering
• nal_at_rice.edu

2
What are Quantum Dots?
IV
V
VI
III
II
II-VI ZnS, ZnSe, CdSe, CdTe, CdS,
HgS III-V GaAs, GaN, InP, InAs,
InGaAs IV-VI PbS, PbSe
3
What do Quantum Dots look like?
4
Quantum dots 2 - 6 nm
5
How are they made?
6
Synthesis Movie
http//www.youtube.com/watch?v2XfFQKEfCcwfeature
related
7
Why do we care?
Medintz et al. Nature Mat., 4, 2005.
8
Luminescence
Excited State
Energy
Fluorescence (emission)
Absorption (excitation)
Ground State
9
Electromagnetic Spectrum
400 nm
700 nm
10
Bare CdSe QD Spectra
11
CdSe/ZnS Excitation-Emission Matrix
12
Water solubilization

• Ligand exchange

Mercaptoundecanoic acid

• Polymer wrapping

Amphiphilic triblock polymer
Polymaleic anhydride oxide - polyethylene glycol
(PMAO-PEG)

• Silica shelling

2-methoxy(polyethleneoxy)propyl-trimethoxysilane
(PEOS)
3-aminopropylmethyldimethoxysilane (APS)
3-mercaptopropylmethyldimethoxysilane (MPS)
13
Particle Aggregation
14
How are they used?
Sapsford et al. Sensors, 6, 2006
Parungo et al. JTCS, 129, 2005
Gao et al. Nat.Biotech., 22, 2004
Green, Angew. Chem., 43, 2004
Michalet et al. Science, 307, 2005
15
Tumor Tissue Margin Detection
16
NIR Optical Window
17
Toxicity Concerns
Low pH - lysosomes Oxidation - peroxisomes
18
(No Transcript)
19
Lewinski et al. Small, 4, 2008
20
Daphnia magna
4x Brightfield
21
Qdot Localization
Rectum
10x Brightfield
10x Fluorescence (DAPI excitation filter)
22
Take Home