Photosensitive complexes of hydrophobically modified polymers, micelles of surfactants and enzymes.

1
Photosensitive complexes of hydrophobically
modified polymers, micelles of surfactants and
enzymes.
Juliette RUCHMANN, ESPCI, Paris, France Macro
2008, Taipei, June 29 - July 4
2
Stimuli-responsive systems of polymer and
surfactant
Polymer hydrophilic/ hydrophobic
stimuli pH, T, light
protein refolding
sol/gel transition
association polymer / surfactant multiple
applications
3
Light-stimulated association
non invasive and focused stimuli

• photo-polymer non responsive surfactant
• macroscopic response to light
• study of physico-chemical parameters

4
Azobenzene-modified polymer
Structural parameters

• chain length (Mn)
• small 7,500 g/mol
• long 42,000 g/mol or 60,000 g/mol
• amount of modificationx 1 - 5
• NMR
• spectroscopy UV-visible

Irradiation
UV 365 nm
blue 436 nm
cis
Surfactant
TX 100
trans
42_3.5C6azo
x 3.5 / Mn42,000g/mol
5
Light-responsive complexes
Static light scattering
1/ mixture complexes formation
2
3
1
(A.U.)
2/ UV light partial photo-dissociation
mixture
42_3.5C6azo
UV light
Blue light
TX 100
in the dark
3/ Blue light re-association
reversible photo-association / photo-dissociation
several cycles for hours
J. Ruchmann, S. Fouilloux, C. Tribet, Soft
Matter, in press
6
Light-responsive complexes
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Transfer of the azobenzene from water into the
micelles
UV visible spectrophotometry
(O.D.)
bound azobenzene
8
Necklace composition
binding isotherm
Electrophoresis
neutral reference
complexes (anionic)
TX100 (neutral)
continuous injection
bound surfactants
9
3 regimes of association
bound surfactants
bound azobenzenes
cmc
10
Light-responsive complexes
2
3
42_5C6azo
Electrophoresis
blue irradiation UV irradiation
60 dissociation
light-response in a large range of compositions
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Influence of different parameters
small chain length
60 photo-dissociation
7.5_4C6azo
42_5C6azo
30 photo-dissociation
TX 100bound/polymer (g/g)
low ionic strength
1 modification
70 photo-dissociation
almost no association
42_5C6azo
42_1C6azo
TX 100free (g/L)
TX 100free (g/L)
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Applications
AMPs protein (BSA) ? photo-responsive physical
gels
G. Pouliquen and C. Tribet, Macromolecules, 2006.
39(1), 373-383

• AMPs neutral surfactants
• ? reversible photo-control of
• emulsion
• S. Khoukh, et al., Chemphyschem, 2005. 6(10),
  2009-2012

J. Ruchmann, S. Fouilloux, C. Tribet, Soft
Matter, in press
13
Protein refolding

• AMPs enzyme (BCA)

no aggregation
association
soluble complexes
unfolded protein
REFOLDING

refolded protein
dissociation
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Protein refolding
dissociation


association
quenching
no quenching
Fluorescence
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CONCLUSION photo-control of association/dissociati
on with micelles and more generally with
hydrophobic colloids (proteins )
Christophe TRIBET Agnès PALLIER Sarah FOUILLOUX
Acknowledgements
ANR-06-BLAN-0174  and BLAN07-3_190727 French
ministery of research
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3 regimes
1
3
2
cmc
?
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Association with surfactants
Rh(complexes) Rh(polymer isolated
chains) Rh(complexes)BLACK Rh(complexes)UV

• well define complexes
• no aggregation

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AMP multiple association onto an hydrophobic
cluster.

• balance between
• loop free energy
• free energy of transfer of azobenzene between
  water and the micelle