[PPT] - Sol-gel derived bioactive glass/natural polymer nanocomposite PowerPoint Presentation

SLIDE 1

Sol-gel derived bioactive glass/natural polymer nanocomposite scaffolds

Oliver Mahony Ruth Hanly Julian Jones

SLIDE 2

Project

Goal

– Develop a bone tissue regenerating scaffold suitable for in situ bone tissue repair

Strategy

– Combine the osteoinductive characteristics of bioactive glass – With tough natural polymers – Gelatin g p y – In class II nanocomposite

GPTMS

SLIDE 3

Presentation outline

Characterisation of class II materials

– C-factor: 0 – 2000

Techniques

– FTIR – Dissolution study – Raman

Preliminary macroporous scaffolds

Preliminary macroporous scaffolds

SLIDE 4

FTIR - Class II nanocomposites

As C-Factor increases the

C-Factor Si-O

Si-NBO peak disappears.

As C-Factor increases the

influence of the C-O-C/Si-

2000 1500 Amide I Amide II

CH2 peak becomes visible.

Oxirane peak becomes

visible in high C-Factor

1000

sorbance

500

samples.

100

Abs

250 Si-O-Si C-O-C/ H d li d Si-NBO Oxirane

2000 1800 1600 1400 1200 1000 800

C-O-C/ Si-CH2 Hydrolised GPTMS

Wavenumber (cm

1)

SLIDE 5

Dissolution study

C Factor 1500 C F t 100 C-Factor 500 13 Days C-Factor 1500 C-Factor 100 C Factor 500

Amide III peak is

8 Days

reduced at longer time points in SBF

Indicates polymer is

3 Days

Absorbance

5 Days

bsorbance Absorbance

dissolving out of the material

With more cross

y

A

2 Days

A A

linking this process is slowed

C-Factor 1500 shows

id III ft 13

1 Day 6 Hours I retch III

amide III after 13 days

1800 1600 1400 1200

Wavenumber (cm

1)

1800 1600 1400 1200

Wavenumber (cm

1)

1800 1600 1400 1200

Wavenumber (cm

1)

Amide CH Str Amide

SLIDE 6

Foam Scaffolds

Extremely high toughness
Stable in solution
Large pore interconnects

SLIDE 7

Conclusions

GPTMS is working successfully to functionalise gelatin

g y g therefore modifying material properties

– Improves silica network condensation – fewer NBOs Improves stability in solution – Improves stability in solution

Materials can be foamed using a novel foaming – freeze-

drying method

– Scaffolds are incredibly tough – Exhibit a pore architecture dictated by foaming process not freeze drying process y g p

SLIDE 8

Samples

SLIDE 9

Colorimetric Absorbance

SLIDE 10

Colorimetric Absorbance

Colorimetric Analysis (Combined results - Normalised)

Absorbance A 100 250 500 1000 1500 2000 C-Factor

SLIDE 11

Nitrogen Adsorption

Modal Pore Size 12 14 6 8 10 nm 2 4 100S-HF (OM) 100S-I- 30G 100S- 100II- 30G 100S- 250II- 30G 100S- 500II- 30G 100S- 1000II- 30G 100S- 1500II- 30G 100S- 2000II- 30G

SLIDE 12

Nitrogen Adsorption

Specific Surface Area p 300 350 150 200 250 m2/g 50 100 100S-HF (OM) 100S-I- 30G 100S- 100II- 30G 100S- 250II- 30G 100S- 500II- 30G 100S- 1000II- 30G 100S- 1500II- 30G 100S- 2000II- 30G

SLIDE 13

FTIR - Functionalised Gelatin

Si-O-Si O i Si-O

As GPTMS is increased

1500II-30G 2000II-30G Amide I Amide II Oxirane C-O-C/ Si-CH2

peak dominance shifts from amide peaks to inorganic silica-oxygen peaks

1000II-30G 500II 30G

bance

As GPTMS is increased the

intensity of the oxirane peak increases

500II-30G

Absorb

Si-O-Si peak may be

indicative of crosslinking

ccurring between GPTMS

molecules

100II-30G

molecules

2000 1800 1600 1400 1200 1000 800

Wavenumber (cm

1)

SLIDE 14

Direct Crosslinking of GPTMS

Gelatin Gelatin One bridging and two non bridging

xygens characteristic of functionalised

gelatin. g

SLIDE 15

Probing the local environment of calcium in apatites
using 43Ca solid state NMR and X-Ray absorption Spectroscopy
Ca(1)
Ca(2)
Ca10(PO4)6(OH)2
Mg2+, Na+
CO3

2-, HPO4 2-…

43Ca solid state NMR
Ca K-edge EXAFS
Ca K-edge XANES
Simulations
Site preference (at high field)
Preedge intensity
Distortion around the Ca
Average Ca-O distance
in 1st sphere
Changes in the 2nd
δiso
Average Ca-O distance
PQ
Distortion around the Ca
Edge position
Coordination number of Ca
Ca10-xMgx(PO4)6(OH)2
Natural apatites
(horse bone cow tooth)
coordination sphere

Q

Disorder around the Ca

(horse bone, cow tooth)

Location of magnesium?
Structure around the calcium?

SLIDE 16

Probing the local environment of calcium in Ca10-xMgx(PO4)6(OH)2
using 43Ca solid state NMR
Natural abundance 43Ca solid state NMR at 18.8 T
Ca(2)
Ca(1)

80 silicates

0% Mg

20 40 60 aluminates phosphates borates carbonates

d δiso (ppm)

8% Mg
12% Mg
40
20
calculated
δ(ppm)
-300
-200
-100
100
200
300
12% Mg
60

2.35 2.40 2.45 2.50 2.55 2.60 2.65 2.70 2.75

Average d(Ca…O) (in Å)

(pp )

43Ca NMR seems to show that
Mg enters the Ca(2) site.

SLIDE 17

Probing the local environment of calcium in Ca10-xMgx(PO4)6(OH)2
using Ca K-edge X-Ray absorption Spectroscopy
0 % Mg
EXAFS
XANES

k3χ(k)

0 % Mg

15 % Mg
0% Mg
15% Mg

d absorption

4
6
8
10
k (Å-1)
Normalized
FT of k3χ(k)
0 % Mg
15 % Mg
Relative edge position (eV)
-5
5
10
15

Ca O shell: 2nd shell:

1
3
5
7
9
r (Å)
The local geometry around the calcium
is hardly distorted after incorporation of
Mg in the apatite lattice.
Ca…O shell:
Hardly any change in

Ca…O distances in Mg-HA sample

2nd shell:
Decrease in intensity
in Mg-HA:
presence of Mg in the lattice

and loss of crystallinity

SLIDE 18

Probing the local environment of calcium in bone and tooth
using 43Ca solid state NMR

14 1 T MAS 4kH

43Ca NMR :
Ca K-edge XANES :
14.1 T, MAS 4kHz
RAPT-1pulse,
24h/spectrum
bone

d •absorption

Ca10(PO4)6(OH)2
bone
Ca10(PO4)6(OH)2
Normalized
Relative •edge •position (
eV)
5
10
15
5
5
10
15
5
-5
10
15
5
δ(ppm)
-200
-150
-100
-50
50
100
150
200
Stronger intensity of the pre-edge:

more distorted environment

around Ca in bone
Comparison of the 43Ca NMR spectra
of bone and apatite:
►δmax of bone at higher frequencies than apatite

sample : maximum Ca-O distance in the 1st shell li htl l i b ? around Ca in bone slightly longer in bone ?

►fwhm in bone bigger than for apatite sample :

stronger distribution of chemical shifts and bigger distortion around Ca?

SLIDE 19

Probing the local environment of calcium in bone and tooth
using calcium K-edge EXAFS
Ca10(PO4)6(OH)2
Tooth
Bone
Crystallinity:
agrees with XRD
HA > tooth > bone
Average Ca-O bond distance in the 1st sphere:
HA ~ tooth < bone

agrees with XRD

agrees with NMR

SLIDE 20

Kent ● Warwick ● Imperial ● UCL

Sol-Gel Partnership Meeting Sol-Gel Partnership Meeting

Friday 29th August 2008 Department of Physics University of Warwick University of Warwick

SLIDE 21

XAS measurements of Zn Ti Phosphates p

Phosphate glasses of composition

(P O ) (CaO) (Na O) (TiO ) (ZnO) (P2O5)50(CaO)30-x(Na2O)15(TiO2)5(ZnO)x

[O]/[P]=3.05 ~ Metaphosphate
Zn K-edge XAS data collected on station

9.3 at Daresbury

Probe the local environment of Zn (first

and second neighbour information) g )

EXAFS data fitted with EXCURV98

SLIDE 22

EXAFS of Zn Ti Phosphates p

ZnO parameters agree

with tabulated values

10

8
6
4
2

2 4 6 8

k^3 chi(k)

N gives 6 coordination
R is consistent with 4

6 8 10 12 14 16 18 20 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

12
10

T k^3 chi(k) k (ang^-1)

ZnO

R is consistent with 4 coordination

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0

2

2 4

FT r (ang)

4 6 8

)

Sample Neighbour R N d/w factor

18 2 3 4 5 6 7 8 9 10 11 12 13

10
8
6
4
2

2

k^3 chi(k)

ZnO O 1.96 3.94 0.00846 Zn 3.22 11.97 0.01810 O 3.75 9.17 0.01405 Zn 4.57 7.13 0.01834

2 4 6 8 10 12 14 16 18

FT k^3 chi(k) k (ang^-1)

T5Z5

T5Z5 O 1.95 6.17 0.01616 P 3.11 1.08 0.00941 T5Z3 O 1.95 6.05 0.01606 P 3.09 1.03 0.00911

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0

2

r (ang)

T5Z1 O 1.95 6.41 0.01755

SLIDE 23

XANES of Zn Ti Phosphates p

Results have characteristics of both four- and

six-coordinated environments

Sample has similarity with both crystalline Zn

sulfate and Zn phosphate Mi t f 4 d 6 di ti ?

Mixture of 4 and 6 coordination?

1.0 1.2

)

0.2 0.4 0.6 0.8

Absorption (A.U.)

0 8

0.6
0.4
0.2

0.0

Normalised A Sample T5Z5 Zn sulfate standard (6) Zn Phosphate (4)

9600 9650 9700 9750 9800 9850 9900

1.0
0.8

Photon Energy (eV)

SLIDE 24

Possibilities

Samples ground into fine powder for the

experiment p

Zn phosphate tetrahydrate has a 4 and 6

coordinated site 4 site is made up of 4 NBOs 6 site is made up of 4 NBOs + 2 water ligands p g

Has sample become hydrated?

Proton NMR? Proton NMR? UV-vis and IR to look for change in water peak with heating? g

SLIDE 25

Q

4

29Si MAS NMR
Gowsh’s Hybrids

T species Q

2

Q

3

HC2192* HC2189a2 T species

40
60
80
100
120
140

δ (ppm)

HC2189a1

Sample Peak 5 (T2) Peak 4 (T3) Peak 3 (Q2) Peak 2 (Q3) Peak 1 (Q4) δ (ppm) FWHM (ppm) I % δ (ppm) FWHM (ppm) I % δ (ppm) FWHM (ppm) I % δ (ppm) FWHM (ppm) I % δ (ppm) FWHM (ppm) I % HC2189a1

61.2

2.78 1

64.6

4.29 1

92.3

5.15 2

101.9

6.43 24

111.6

9.19 72 HC2189a2

65.0

3.44 1

93.4

6.22 3

102.0

7.97 25

111.5

9.24 71 HC2192*

62.3

4.57 2

92.5

5.03 2

101.4

8.58 25

111.0

9.04 71

SLIDE 26

13C CP MAS NMR
Hybrids containing collagen (C) and gelatin (G) – Oli’s samples

C H COOH NH2 H N COOH N COOH O H C H COOH NH2 H3C α H

α β γ δ

H

α β γ δ

α

β sα, Pheα β, Ileβ Leuα Leuγ

2

Glycine Proline Hydroxyproline Alanine

CO Proα, Hypα,Lys Pro δ Glyα, Argδ Alaβ ypγ spβ, Lysε, Leuβ, Pheβ Ala α , Argα,Aspα, Serα, L Gluγ, Lysδ, Ileγ Proγ, Gluβ, euδ, Valγ,γ', Thrγ

S100H8Gel30 S100NGel20

ssb ssb ssb Pheδ,ε ssb Hy Hypβ, As Hypδ, Gluα Le

S100NGel20 C12 S70NGel30

CH3

CH2O

300 250 200 150 100 50

50
100

80 70 60 50 40 30 20 10

δ (ppm) δ (ppm)

C12

C

SLIDE 27

Synthesis

SOL GEL PROCESSING

SOL – GEL PROCESSING
TEOS, calcium chloride and triethyl phosphate as SiO2, CaO and

P2O5 precursors

________________

________________Parameters of the sol Parameters of the sol-

gel synthesis

gel synthesis____________________________ ____________________________

Sample CaO (%) P2O5 (%) TEOS/EtOH/H2O (H2

17O)/HCl Form

S100 -
1 : 2 : 2 : 0.02 transparent
S90 10 -

1 : 2 : 2 : 0.02 transparent

S70 30 -

1 : 2 : 2 : 0.02 transparent

S50 50 -

1 : 2 : 2 : 0.02 transparent

S77 16 4 1 : 2 : 2 : 0.02 transparent
S58 36 4 1 : 2 : 2 : 0.02 transparent

SLIDE 28

FTIR – SBF – HC2199

HF catalyst
More stable in SBF
No Catalyst
HC2199 1hr
HC2199 24hrs
HC2199 3days
Si-O
1073
P-O
HC2213f 1 hr
HC2213f 24 hr
HC2213f 3 days
Si-O
1073

bance

Amide I & II
575
P-O
600
P-O
575
P-O
600
Amide I & II
Absorb
Wavenumber (cm-1)
4000
1000
500
2000
2800
Wavenumber (cm-1)
4000
1000
500
2000
2800

Wavenumber (cm ) ( )

SLIDE 29

SBF – ICP

SLIDE 30

SEM of SBF Samples
HC2199
HC2199 after 3 days

SLIDE 31

SEM of SBF Samples
5 µm
HC2 213
after 3
days

Element Weight % Atomic % O 63 09 78 79

O
HC2 213

O 63.09 78.79 Si 1.12 0.82 P 11.67 7.56

P
Ca

Ca 20.34 10.15

Ca/P = 1.3
1
2
3
4
5
6
7
Ca
Si
Cl
Ca

SLIDE 32

This study : This study :

(45mol%) (45mol%)P2O5 (30) (30)CaO

CaO (25

(25-

x)

x)Na

Na2O (x)

(x)TiO

TiO2

{x=0,1,3,5,10,15} {x=0,1,3,5,10,15} (55mol%) (55mol%)P2O5 (30) (30)CaO

CaO (15

(15-

x)

x)Na

Na2O (x)

(x)TiO

TiO2

2 5 2 2

{x=0,1,3,5} {x=0,1,3,5}

SLIDE 33

D it f PG f ti f TiO t t Density of PGs as a function of TiO2 content

y = 0.0071x + 2.6284 2.75 2.8

P45 P55

R

2 = 0.9886

2.7

y (g.cm-3)

y = 0.0036x + 2.5585

2

2.6 2.65

Density

R

2 = 0.9591

2.55 3 6 9 12 15 18

TiO2 content(mol%)

SLIDE 34

Thermal analysis data of P45 and P55 Thermal analysis data of P45 and P55

800 600 700 ature (C) P45- Tg P45- Tc 400 500 Tempera P55- Tg P55- Tc 300 2 4 6 8 10 12 14 16 TiO2 content (mol%)

Tg and Tc increase with TiO2 incorporation in both P45 and P55 PGs.
P45-Ti %15 with the highest Ti content has the highest Tg and Tc.

SLIDE 35

Degradation of PGs as a function of TiO2 content

y = 1E-05x + 8E-05 R

2 = 0.9922

0.01 0.01 %.mm-2) P45-Ti %15 P55-Ti %5

R 0.9922

0.00 0.00 weight loss (%

y = 2E-06x - 2E-05 R

2

0 968

0.00 0.00 Cumulative w

R

2 = 0.968

0.00 50 100 150 200 250 300 350 400 Ti (h) C Time (h)

SLIDE 36

HT-XRD and DTA graph of P45-Ti%15 HT XRD and DTA graph of P45 Ti%15

1000 1100

re (°C )

700 800 900

T e m p e ra tu r

400 500 600 60 100 200 300 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39

Crystallised phases are identified from XRD at room temperature :

NaCa(PO3)3

TiP O

2-Theta - Scale

TiP2O7
ßCaP2O6

SLIDE 37

HT-XRD and DTA graph of P55-Ti%5 HT XRD and DTA graph of P55 Ti%5

900 1000 1100

u re (°C )

600 700 800

T e m p e ra tu

400 500 600 50 100 200 300 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39

Crystallised phases are identified from XRD at room temperature :

NaCa(PO3)3

2-Theta - Scale

20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39

(

3)3

TiP2O7

SLIDE 38

Formation of amorphous calcium phosphate and hydroxyapatite on melt quenched Bioglass using surface sensitive shallow angle X-ray diffraction

Intensity

quenched Bioglass using surface sensitive shallow angle X ray diffraction

Incident
X-ray beam
Diffracted
e-l
Intensity
Detecto

r

αi
αi
Thin

film

z
2θ
2θ'

Diffracted

X-ray

beam

Penetratio

n depth z ↓

film

Substrate
z = l sin(αi)

Incident angle, αi, (º) Penetration depth, z, (µm) Bioglass Octacalcium phosphate

µ α α

α i c i

z = >

0.2 0.8 0.6 0.5 2.0 1.5 1.0 3.9 3.1 1 6 6 2 4 9 1.6 6.2 4.9

SLIDE 39

0.0 0.4 (a.u.)

0 8 1

The diffraction pattern of Bioglass as a

function of incident angle for (a) unreacted

0.8
0.4

1.4 1.8 2.2 2.6 Q (Å-1) S(Q)

0.4 0.6 0.8 ntensity (a.u.)

function of incident angle for (a) unreacted Bioglass; the inset shows the diffraction pattern for the unreacted Bioglass compared to the pattern obtained by FitzGerald et al using conventional high

0.2 In

g g energy X-ray diffraction, (b) Bioglass reacted in SBF for 24 hours and (c) Bioglass reacted in SBF for 3 days. The incident angles; 1.6 º, 1.0 º, 0.5 º and 0.2º are given from top to bottom

1 1.5 2 2.5 3 3.5 4 Q (Å-1) 1 3

are given from top to bottom,

0.6 0.8 sity (a.u.) 2 sity (a.u.) 0.2 0.4 Intens 1 Intens 1 1.5 2 2.5 3 3.5 4 Q (Å-1) 1 1.5 2 2.5 3 3.5 4 Q (Å-1)

SLIDE 40

0.6 0.5 0.4 (a.u.)

The diffraction pattern of

0 2 0.3 Intensity

The diffraction pattern of Bioglass reacted in SBF for varying periods of time. All data sets were collected with an angle of incidence of 1.6 º.

0.1 0.2 1 1.5 2 2.5 3 3.5 4 1 1.5 2 2.5 3 3.5 4 Q (Å-1)

SLIDE 41

18 14 16 10 12 .u.)

The diffraction pattern of Bioglass reacted

8 10 Intensity (a

in SBF for 0, 4, 24 and 72 hours followed by heating treating at 650 º C are given by b, c, d and f respectively. The diffraction pattern

f Na6Ca3Si6O18 and Hydroxyapatite are

given by (a) and (e) respectively All data

4 6

given by (a) and (e) respectively. All data sets were collected with an angle

f

incidence of 1.6 º.

2 1 2 3 4 Q (Å-1)

SLIDE 42

Antibacterial Gallium Doped Sol- Gel Glasses

Helen Twyman

SLIDE 43

Previous work

Had produced 2 glasses: (SiO2)0 7(CaO)0 3 and

p g (

2)0.7(

)0.3 (SiO2)0.7(CaO)0.275(Ga2O3)0.025

Ran XRD, EXAFS and XANES on both.
Tested negative for antibacterial activity.
Decided to introduce Na2O as a network modifier to

disrupt the SiO network and increase to solubility of the disrupt the SiO2 network and increase to solubility of the silica to allow Ga3+ ions to be more readily released.

SLIDE 44

Recent work

Produced 2 glasses with 10 mol% Na2O, one with Ga

g

2 ,

and one without: (SiO2)0.6(CaO)0.3(Na2O)0.1 and (SiO2)0.6(CaO)0.275(Na2O)0.1(Ga2O3)0.025 G t i i l d t b tib t i l i t

Ga containing sample proved to be antibacterial against

Pseudomonas aeruginosa.

XRD EXAFS XANES and SAXS have been performed
XRD, EXAFS, XANES and SAXS have been performed
n both samples but data is yet to be analysed.

SLIDE 45

Future work

Analysis of data already obtained.

y y

Analysis techniques to be performed:

Bioactivity assessment Solubility assessment TGA/DTA BET

SLIDE 46

Solid-State NMR Group

chain-length statistics in a phosphate glass using NMR

REfocused INadequate spin-Echo REINE

SLIDE 47

Solid-State NMR Group

P1 — P2 — P1 P1 — P2 — P2 — P1 P1 — P2 — (P2 —)n P2 — P1

ref. INAD. peaks and

phosphate chain lengths

P1 — P1

P1 — P1 P1 — P2 P2 — P1 P2 — P2

P0

SLIDE 48

Solid-State NMR Group

phosphate chains and J-modulations

P1 — P2 — (P2 —)m P2 — P1

P1 — P1

P1 — P2 — P1 P1 — P2 — P2 — P1

n2 × 2 × cos(1—1) (n3 + n4 + n5+) × 2 × cos(1—2) (2×n4 + 2×n5+) × cos(1—2) × cos(2—2) n5+ × m × cos2(2—2) P1 peaks P2 peaks n3 × cos2(2—1)

SLIDE 49

Solid-State NMR Group

J-modulations of

ref. INAD. peaks

P1 — P1 P1 — P2 P2 — P1 P2 — P2

cos(πJ11τj) n3 × cos2(πJ12τj) + (n4 + n5+) × 2 × cos(πJ12τj) × cos(πJ22τj) cos(πJ12τj) n5+ × cos2(πJ22τj) + n4 × 2 × cos(πJ12τj) × cos(πJ22τj)

SLIDE 50

Solid-State NMR Group

5 10 15 20 25 30 35 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

J1 = 13.9 ± 0.8 Hz J2 = 7.9 ± 0.5 Hz T2’ = 33.2 ± 3.6 ms

τj / 2 / (ms) Intensity / (a.u.) 5 10 15 20 25 30 35 40 0.2 0.4 0.6 0.8 1

J1 = 13.8 ± 0.5 Hz J2 = 6.8 ± 0.5 Hz T2’ = 35.9 ± 3.3 ms

τj /2 / (ms) Intensity / (a.u.)

cos(πJ12τj) × cos(πJ22τj) × exp(−τj/T2’) same J-modulation suggests P2 units are mostly in tetra-phosphate chains structure of glass: mostly di- and tetra-phosphate chains