Aucun titre de diapositive

1
bio-inspired nanomaterials
Jacques Livage - Collège de France
Sao Paulo - 14.09.09
2
The history of materials starts almost 3
millions years ago
Cutted stone
homo habilis
Polished stone
3
Only natural materials such as wood, stone and
bones were used
4
(No Transcript)
5
5
The history of mankind follows the development of
materials
copper
bronze
stone
iron
6
today is the age of silicon and nanomaterials !
7
Making advanced materials requires higher
temperatures and more sophisticated techniques
Materials chemistry Shake bake chemistry
would it be possible to make advanced materials
under soft conditions ?
Chimie douce - Soft chemistry
8
(No Transcript)
9
(No Transcript)
10
10
Diatoms
single cell photosynthetic micro-algaes
consume 20 of the whole CO2 produced by man
live inside a silica cage called frustule
11
Charles Darwin
origin of species 1859
Why are diatoms silica shells so beautiful, is
it just to enjoy our eyes ?
12
200.000 tons/year in France
13
I Diatom Nanotechnology
Fast production of large amounts of identical
porous silica shells
14
Diatoms all-made 3D nanostructured materials
15
15
Diatoms as living gas sensors
Highly porous silica frustules
Large gas-solid interface
16
Large gas-solid interface
Photoluminescence of silica
very sensitive sensors detection limit 0.1 ppm
17
Diatoms as living photonic crystals
Periodic distribution of pores
18
photons in photonic crystals behave like
electrons in semi-conductors
19
Lensless light focussing with diatom
De Stefano et al. Optics express 15 (2007) 18082
diatom behaves as a microlens
focalisation of light on chloroplastes for
photosynthesis
20
20
Nano-lasers
21
The  BaSIC process
Bioclastic and Shape-preserving Inorganic
Conversion
K.H. Sandhage et al. J. Am. Ceram. Soc. 88 (2005)
2010
22
(No Transcript)
23
Diatoms 3D nanostructured materials with photonic
and electronic properties
24
(No Transcript)
25
25
Biogenic synthesis of silica by diatoms
Si(OH)4
26
Silica is synthesized inside the cell in Silica
Deposition Vesicles
Then deposited outside to form the shell
(frustule)
27
Diatom division
the new silica frustule is formed within 1 or 2
hours
28
Diatom division
the new silica frustule is formed within 1 or 2
hours
29
(No Transcript)
30
30
inorganic polymerization
The sol-gel process
31
1845 first publication C.R. Académie des
Sciences 1939 first patent by Schott
Glaswerke Sol-gel coatings on glasses 1959
commercialization 1981 first
international scientific meeting
J.J. Ebelmen
1959 rear-view mirrors 1964 anti-reflecting
coatings 1969 anti-caloric coatings (calorex,
Irox)
32
Powderless Processing of Glasses Ceramics
33
Hybrid organic-inorganic nanocomposites
inorganic chemistry organic chemistry room
temperature metal-organic precursors in organic
solvents
a whole range of new materials from brittle
glasses to plastic polymers
34
sol-gel optics
Organic dyes in a silica matrix
Organic dyes protected in a silica matrix easily
shaped materials (molding, polishing) nano-composi
te transparency
Fraunhofer Würzburg
fluorescence laser non linear optic photochromism
35
35
Organic-inorganic hybrids
Roof of the National Theater of Bejing
Beijing Zhang Saina Glass Technology
36
Enzyme immobilization on solid substrates
mainly with organic or bio-polymers
advantages of silica substrates
mechanical properties chemical stability no
sweling in water
37
Encapsulation within sol-gel silica
38
Trapped enzymes retain their catalytic
activity their lifetime increases significantly
(x 100)
Enzymes are protected by the silica matrix
39
Protection of alkaline phosphatases against pH
H. Frenkel-Mullerad, D. Avnir, JACS (2005)
inside nanopores
103 H2O
only 2 H3O
40
40
organic syntheses oil chemistry food medecine
41
Interfacial activation of Lipases
42
Sol-gel lipases
M. Reetz - Max Planck
43
Immobilized Enzymes    62272 Lipase, imm. In
Sol-Gel-AK on sintered glass. Cand.
Antarc   62274 Lipase, imm. In Sol-Gel-AK on
sintered glass, Mucor miehei   62275 Lipase,
imm. In Sol-Gel-AK on sintered glass, Pseud.
Fluor   62277 Lipase, imm. In Sol-Gel-AK, from
candida antarctica   62278 Lipase, imm. In
Sol-Gel-AK, from Candida cylindracea   62279 Lipa
se, imm. In Sol-Gel-AK, from Pseudo-monas
cepacia   62281 Lipase, imm. In Sol-Gel-AK, from
Asper-gillus niger   62282 Lipase, imm. In
Sol-Gel-AK,from Mucor miehei   62283 Lipase,
imm. In Sol-Gel-AK, from Pseudo-monas
fluorescens   62319 Lipase, imm. On Eupergit C
from Pseudo-monas fluorescens   62324 Lipase,
imm. In Sol-Gel-AK, from hog pancreas   62334 Lip
ase, imm. In Sol-Gel-AK on sint. Gl., Pseudom.
Cepacia  
Commercialized by  Fluka 
44
Enzymes can be incorporated into electronic
devices to make biosensors
Glucose Oxidase
Oxidation of glucose by molecular O2
Diabete sugar titration in blood
45
45
Electrochemical titration of O2
Oxygen titration via a Clark electrode
46
Optical titration via a double enzymatic reaction
1 Oxidation of glucose via GOx
2 Oxidation of a dye by H2O2 via HRP
X colored dye
Both enzymes are trapped in the silica matrix
HRP Horse Radish Peroxidase
47
Pin-printed sol-gel micro-arrays
J.D. Brennan et al. Chem. Mater. 15 (2003) 1803
Ink-jet printer
M. Lejeune et al. J. Am. Ceram. Soc. 89 (2006)
1876
48
III Life in glasses !
Is it possible to keep living micro-organisms in
silica ?
bacteria - yeasts - plant cells - animal cells
49
Sol-gel encapsulation of whole cells
first paper by G. Carturan et al. J. Mol. Catal.
57 (1989) L13
bacteria - yeasts plant cells - animal cells
50
50
alcohol is toxic for bacteria
51
Encapsulation in aqueous silica gels
diluted solution to avoid precipitation silica
colloïds (Ludox) to improve mechanical properties
52
Enzymatic activity of E. coli
53
Enzymatic properties of E. coli are preserved
54
enzymatic activity does not mean that bacteria
are still alive bacteria bag of enzymes
55
55
Viability of E. coli in silica gels
Cell division
12h 37C
formation of colonies in a culture medium
Colony Forming Units
The viability of trapped bacteria decreases very
quickly
56
Using additives to protect the cell and improve
viability
glycerol
57
Formation of a protecting glycerol layer around
the cell
without glycerol
with glycerol

retain water around the cell
avoid interactions with silica
58
Incorporation of living cells into silica-based
nanostructures
cells phospholipids silicic acid
Fluorescence microscopy shows that cells are
surrounded by a protecting phospholipid layer
59
(No Transcript)
60
60
Sol-gel encapsulation can be extended to other
oxide matrices
Cells are protected by glycerol
Long term viability
SEM
Alumina gels
Iron oxide gels
TEM
61
The metabolic activity of trapped bacteria is
preserved
E ethanol L lactate A acetate S
succinate
62
The miracle of Bolsena 1263
bleeding host
Blood spots on bread
63
Serratia marcescens
Produce a red pigment
Prodigiosin
64
Prodigiosin new drug with therapeutic properties
induces apoptosis of cancer cells
65
65
Prodigiosin production by Serratia marcescens
better activity in gels
66
Bacteria are isolated within the silica matrix
No chemical communication between bacteria
67
Chemical communication between bacteria
Quorum sensing molecules control the metabolic
activity bioluminescence, biofilm formation,
sporulation, pigment production,
68
Q.S. molecules enhance the production of
prodigiosin
The metabolic activity of bacteria is modified by
QS molecules
69
Q.S. molecules improve the viability of bacteria
almost 100 bacteria are still viable after 1
month with C6
Q.S. favors entry into stationary state resulting
in increased resistance to environmental stresses
70
44
70
Immunology
Immuno-assays are based on the specific
recognition between antigens and antibodies
71
(No Transcript)
72
(No Transcript)
73
ELISA blood tests Enzyme Linked ImmunoSorbent
Assays
La Pitié Salpétrière hospital - Paris
wells 300ml
encapsulation of Leishmania cells in each wells
of a titration plate
74
Leishmania cell trapped in silica gels
TEM
Immuno-assays are performed with whole cells as
antigenic materials
Leishmania cells at the promastigote stage are
trapped within silica gels in the wells of the
titration plate
75
Blood tests in silica gels
Specific detection of antigens by antibodies
occurs in silica gels
75
76
Encapsulation of Langherans islets
Langerhans islets in the pancreas are involved
in the metabolism of glucose
diabete
Solgene Therapeutics
E. Pope - USA
77
Cell transplantation
78
transplanted cells are protected
against immuno-rejection by the porous silica
membrane
no inflamation
79
IV Encapsulation within hybrid microcapsules
Towards living materials !
80
80
Alginate beads are currently used for cell
encapsulation
Polysaccharide cross linked by Ca2
good bio-compatibility swelling in water poor
mechanical properties
81
core-shell hybrid microcapsules
Silica coating
prevents swelling diffusion control mechanical
properties
? mm
82
Micro-algaes as cell factories
Bao-Lian Su et al. J. Mater. Chem. (2008)
R. Brayner et al. New J. Chem. (2005)
83
(No Transcript)
84
Biosynthesis of Au nanoparticles by cyanobacteria
R. Brayner et al. J. Nanoscience Nanotechnology
7 (2007) 2696
85
85
Bio-synthesis of b-FeOOH nanorods by cyanobacteria
R. Brayner et al. Langmuir (2009)
Trapped cyanobacteria can survive several
months but they dont have enough space to divide
!
86
Encapsulation of diatoms
Photo-synthetic activity of living
diatoms  brown algae 
O2 bubbles
life time gt several months
87
Diatoms are able to divide inside silica gels
88
Dissolution of the silica gel around living
diatoms
C. Gautier et al. Chem. Commun. 2006, 4611
Silica dissolution by trapped diatoms
no void around dead cells
The empty space increases with time
How can we provide more space for trapped cells
to divide ?
89
(No Transcript)
90
90
alginate beads (? 3 mm) are trapped within a
silica gel
Ca2-alginate is dissolved by adding citric acid
to provide space for cell growth
cells, trapped in macro-cavities have enough
space to divide
91
trapped cells are protected against contamination
contaminating agents cannot diffuse through the
mesopores
92
Hybrid silica nanoparticles for drug delivery
Nanoparticles can be used as a vector to bring
drugs inside cells
93
Aerosol route toward hybrid nanoparticles
mean diameter 100 - 200 nm
Nanoparticles can cross the cell membrane
94
Internalization of nanoparticles by fibroblast
cells
J. Allouche et al. J. Mater. Chem. 16 (2006) 3120
In vivo liberation of CF dyes in fibroplast cells
carboxyfluoresceine CF
M.Boissiere et al.. Int. J. of Pharmaceutics 2007
95
Design of hybrid organic-inorganic nanocapsules
95
M. Boissière et al. Int. J. Pharmaceutics, 344
(2007) 128
R recognize the target
96
Targeting through the membrane of cancer cells
Imaging
Photo Dynamic Therapy
Cell destruction by UV irradiation
dyes are progressively released in the blood
dyes trapped inside nanoparticles cannot escape
97
Silica nanoparticles doped with rare earth ions
(Eu3, Dy3)
Nanoparticles can be excited before
injection their in vivo distribution can be
followed in real time for more than 1 hour
without the need of any external illumination
avoid auto-fluorescence of mammalian tissue
98
Gene Therapy
Introduction of therapeutic genes inside a
target cell
a vector is required to bring these genes inside
the nucleus of the cell
It is usually a virus
99
Why are diatoms silica shells so beautiful is
it just to enjoy our eyes ?
Charles Darwin, origin of species 1859