Nanosensors Hyunkyung Bae Byungmook Kim. Nanosensors Why is it needed? How to make? What to do?
-
Upload
randolf-lloyd -
Category
Documents
-
view
221 -
download
0
Transcript of Nanosensors Hyunkyung Bae Byungmook Kim. Nanosensors Why is it needed? How to make? What to do?
Magnetic properties
Ferromagnetism Paramagnetism. Ferrimagnetism Antiferromagnetism
Ordered and same magnitude without external magnetic field
Disordered without external magnetic fieldIn the external mag-netic field, the mo-ments are ordered.
Aligned oppositely with different magni-tude
Aligned oppositely with the same magni-tudes
Superparamagnetism
• Superparamagnetism is a form of magnetism, which appears in small ferromagnetic or ferromagnetic nanoparticle.
• Neel relxation time < measurement time→average zero magnetic state = superparamagnetic state
• When an external magnetic field is applied to an assembly of superparamagnetic nanoparticles, their magnetic moments tend to align along the applied field, leading to a net magnetization.
N S
Nanoparticle
Optical properties
IGOR L. MEDINTZ1*, H. TETSUO UYEDA2, ELLEN R. GOLDMAN1 AND HEDI MATTOUSSI, Quantum dot bioconjugates for imaging, labelling and sensing, Nature materials 2005
Alexa 488
FITC
GFP Quantum dots
Organic dye
0 10 20 30 40 50 60 70 80 90100
110120
130140
1500
0.2
0.4
0.6
0.8
1
1.2
Photobleaching time
FITC Alexa Flour 488GFP QD 608
Time(sec)
Rela
tive
inte
nsity
Qd is Much Much stable!
3. Nanoruler
• Alexander J. Mastroianni, David A. Sivak, Phillip L. Geissler, and A. Paul Alivisatos, Probing the Conformational Distributions of Subpersistence Length DNA, Biophysical Journal 2009
.
3. Nanoruler
• Alexander J. Mastroianni, David A. Sivak, Phillip L. Geissler, and A. Paul Alivisatos, Probing the Conformational Distributions of Subpersistence Length DNA, Biophysical Journal 2009
.
Dark Field – Gold nanoparticles TIRF Microscopy – Quantum dots
Q dot
Magnetic+Au
Completely matching!
Glass
Strong magnet
TIRF Microscopy
Strong magnet
References• A.P.Alivisatos, Science, New Series, Vol. 271, No. 5251. (Feb. 16, 1996), pp. 933-937• Yadong Yin & A.Paul Alivisatos, NATURE04165, vol 437, 2005• J. M. Yuk, J.W. Park, A. Paul Alivisatos, High-resolution EM of Colloidal Nanocrystal growth using graphene liquid cells, Science 336, 61 (2012) • J. M. Yuk, J.W. Park, A. Paul Alivisatos, High-resolution EM of Colloidal Nanocrystal growth using graphene liquid cells, Science 336, 61 (2012) • Xiaogang Peng, L.Manna, W.Yang, J. Wickham, E.Scher, A.Kadavanich & A.P.Alivisatos, Shape control of CdSe nanocrystals, Nature,vol 404, 2 March 2000• L.Manna, D.J.Milliron, A.Meisel, E.C.Scher, A.Paul Alivisatos, Controlled growth of tetrapod-branched inorganic nanocrystals, nature materials, vol 2,June 2003• Haitao Liu and A.Paul Alivisatos, Preparation of Asymmetric Nanostructures through Site Modification of Tetrapods,Nano Lett., Vol. 4, No. 12, 2004 • Son, D. H.; Hughes, S. M.; Yin, Y. D.; Alivisatos, A. P., Cation exchange reactions-in ionic nanocrystals. Science 2004, 306, (5698), 1009-1012• Robinson, R. D.; Sadtler, B.; Demchenko, D. O.; Erdonmez, C. K.; Wang, L. W.; Alivisatos, A. P., Spontaneous superlattice formation in nanorods through partial cation exchange. Science 2007, 317, (5836), 355-358• IGOR L. MEDINTZ1*, H. TETSUO UYEDA2, ELLEN R. GOLDMAN1 AND HEDI MATTOUSSI, Quantum dot bioconjugates for imaging, • labelling and sensing, Nature materials 2005• Alexander J. Mastroianni, David A. Sivak, Phillip L. Geissler, and A. Paul Alivisatos, Probing the Conformational Distributions of Subpersistence Length DNA, Biophysical Journal 2009