Name

Controllable Aggregation ofFunctionalized Gold Particles by

Ligand-Receptor Mechanism

Friedrich-Alexander-Universität Erlangen-NürnbergLehrstuhl für Feststoff- und

Grenzflächenverfahrenstechnik

Dr. A. Voronov, A.Kohut, Prof.W.Peukert

Name

• Motivation• Avidin-Biotin

Interactions• Experimental

Results• Conclusions and

Outlook

Presentation overlook

Name

Gold particles synthesis and characterization

H[AuCl4]+3

+ Au0

+ KCl + HCl + + H2OCO2C

CH2CHOC

CH2C OOK

O OK

O

KO+ CH3C CH3

O

70 nm400 500 600 700 800

0,0

0,2

0,4

0,6

0,8

1,0

1,2

1,4

0,0

0,2

0,4

0,6

0,8

1,0

1,2

1,4

1,6

maximal adsorbance 519,3 nm

21

2 - Au sol after 30 days1 - Au sol as prepared

Abso

rban

ce

Wavelength (nm)

Abs

orba

nce

TEM AFM (height 25 nm)

Particles size

UV-vis measurements

T, oC Time, min Size, nm100 5 2080 25 16.570 45 18

Chlorauric acid reacts with a sodium citratewater solution at the boiling point

Name

Melting point: 232 – 233oC

Isoelectric point: pH 3.5

Solubility at 25oC in water0.22 mg/ml, in alcohol 0.8 mg/ml

pH of 0.01% aqueoussolution: pH 4.5

Molecular weight 244.31

Biotin compositionC10H16N2O3S

Avidin monomer contains 128 aminoacid residues

Isoelectric point: pH 10

Subunit molecular weight 15.600

Combined molecular weight 67.000

Oligosachcharide 1/subunit, mannose4-5/su, Glucosamine 3/su, tryptophan 4/su

AVIDINBIOTIN

The avidin- biotinInteraction is thestrongest knownnoncovalent and

biological interactionK d = 10 - 15 M -1

COMPLEX- very rapid

- unaffected by pH

- stable up to 130 oC

- stable in organic solvents

- autoclaving breaks it

Avidin - Biotin Interaction

Name

-S-

-S- -S--S--S-

-S-

-S-

-S-

-S-

-S-

-S-

-S-

-S-

+ BDS

+ ODT -S-

-S- -S--S--S-

-S-

-S-

-S-

-S-

-S-

-S-

-S-

-S-

-S-

-S- -S--S--S-

-S-

-S-

-S-

-S-

-S-

-S-

-S-

-S-

(S 2(S 2)

+ Alkylbiotin

+ TGI

-S-

-S- -S--S--S-

-S-

-S-

-S-

-S-

-S-

-S-

-S-

-S-

-OH

-OH

-OH

-OH

-OH-OHHO-

HO-

HO-

HO-

-OH-OH

-S--S-

-S-

-S-

-S--S-

-S-

-S-

-S-

-OH-OH

-OH

-OH

-OH-OHHO-

HO-

HO-

HO- -OH-OH

HO--OH

HO-

HO-

+ BDS

(S 2(S 2)

-S-

-S- -S--S--S-

-S-

-S-

-S-

-S-

-S-

-S-

-S-

-S-

-S-

-S- -S--S--S-

-S-

-S-

-S-

-S-

-S-

-S-

-S-

-S-

-S-

-S- -S--S--S-

-S-

-S-

-S-

-S-

-S-

-S-

-S-

-S--S-

-S- -S--S--S-

-S-

-S-

-S-

-S-

-S-

-S-

-S-

-S-

-S-

-S- -S--S--S-

-S-

-S-

-S--S-

-S-

-S-

-S-

-S-

Gold aggregate domain

HS-

HS- -OH-OH

A

B

C

NHHN

S

O

(CH2)4 C OCH2CH2SO

2

Avidin - tetrameric protein, MW ~ 66,000

NHNH

O

S(CH2)4 OHC

O

Biotin 3propan-1-ol

+ = Biotin 16hexadecan-1-ol

Biotin disulfide(BDS)2-hydoxyethyl disulfide

Modification Routes

Name

UV- and particle sizemeasurements of Au capped with

ODT

400 500 600 700 800

0,0

0,2

0,4

0,6

0,8

1,0

1,2

1,4

5

Au sol after capping with 10-5Moctadecanthiol (ODT)1- as prepared, 2- 15 min, 3- 3 hours4- 6 h, 5- 120 h

43

21

Abso

rban

ce

Wavelength, nm

0 10000 20000 30000

25

50

75

100

125

150

Au + 10-5 ODT

Au + 10-7M ODT

x 50

,3, n

m

time, min

Name

UV-measurements of Au capped with biotin and cross-linked with avidin

400 500 600 700 8000,0

0,2

0,4

0,6

0,8

1,0

avidin addition

Gold + BDS 10-10M + avidin 10-10M (1-168 hours)

43

21

Nor

mal

ized

abs

orba

nce

Wavelength, nm400 500 600 700 800

0,0

0,2

0,4

0,6

0,8

1,0

avidin addition

7

65

4

32

1

1

Gold + ODT 10-7M + alkyl biotin 10-6M + avidin 10-8 M (1-18 hours)

Nor

mal

ized

abs

orba

nce

Wavelength, nm

400 500 600 700 800

0,0

0,2

0,4

0,6

0,8

avidin addition

8765

432

1

Gold+thyoglycerol 10-6M + BDS 10-10M + avidin 10-10M (1-96 hours)

Norm

aliz

ed a

bsor

banc

e

Wavelength, nm

Name

Flocculation parameters

200 400 600 800 1000 1200 140050

60

70

80

90

100

110

120

130Gold+ODT10-7M+ alkyl biotin 10-6M+avidin10-8Mafter avidin addition

Floc

cula

tion

para

met

er

total experimental time, min

2000 4000 6000 8000 10000

20

40

60

80

100

120

Gold +thyoglycerol 10-6M+BDS10-10M+avidin10-10M afteravidin addition

Gold + BDS 10-10M + avidin 10-10M after avidin addition

Floc

cula

tion

para

met

er

total experimental time, min

Name

Particles size and optical spectroscopy characteristics of Au capped with biotin and cross-linked with avidin

0 2000 4000 6000 8000 1000020

40

60

80

100

120

140 no avidin no linker no biotin avidin lower C avidin higher C stabilizer higher C stabilizer lower C

x 50

,3, n

m

total experimental time, min0 1000 2000 3000 4000 5000 6000

0,7

0,8

0,9

1,0

1,1

518

519

520

Gold + 10-6 M thyoglycerol + BDS 10-10 M-avidin 10-10M

λ, nmavidin addition

A (5

19 n

m)

total experimental time, min

0 200 400 600 800 1000 1200

0,6

0,8

1,0

1,2

1,4

500

520

540

560

580

600

620

640

660

A (5

19 n

m)

total experimental time, min

Gold +10-7M ODT+ BDS 10-6 M + avidin 10-8M

avidin additionλ, nm

0 2000 4000 6000 8000 10000

0,9

1,0

1,1

1,2

1,3

500

520

540

560

580

600

620

640

660

Gold + BDS 10-10 M + avidin 10-10Mavidin addition

λ, nm

A (5

19 n

m)

total experimental time, min

Name

ED

Aggregated Gold Colloids

Name

It is possible to predict and to control the size and the structure of nanogold aggregates formed by ligand-receptor interaction

Key factors by the aggregate formation were gold solution stability, time and ligand – receptor ratio

The aggregate structures could be applied for the formation of thin particulate films with a certain morphologies

Conclusions

Name

• - Clarissa Abetz (University of Bayreuth) for the technicalsupport by SEM measuremenns

• - DAAD for the financial support

Acknowledgments