Monodisperse Polymer-Stabilised Water Soluble Gold Nanoparticles

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2 Monodisperse PolymerStabilised Water Soluble Gold Nanoparticles Nicolas SCHAEFFER The University of Liverpool Department of Chemistry Crown street Liverpool L69 7ZD U.K.

3 Stabilization Van der Waals attraction

4 Stabilization Electrostatic repulsion Van der Waals attraction Electrostatic stabilization

5 Stabilization Steric repulsion Van der Waals attraction Electrostatic stabilization Steric stabilization

6 Polymeric stabilization

7 What makes a suitable stabilizer?

8 What makes a suitable stabilizer? Binding site Hydrophobic end Hydrophilic tail J. Am. Chem. Soc.; 2004; 126; 10076

9 Chain transfer polymerization R' Initiation 2 + N 2 N Initiator Chain transfert agent Monomers R S R' J. Macrmol. Sc. Part A; 1999, 36, 51

10 Chain transfer polymerization Chain transfer R S R' J. Macrmol. Sc. Part A; 1999, 36, 51

11 Chain transfer polymerization Chain transfer Initiation R S R' Propagation R S R' J. Macrmol. Sc. Part A; 1999, 36, 51

12 Chain transfer polymerization Initiation R S R' Propagation R S R S R' R' R' J. Macrmol. Sc. Part A; 1999, 36, 51

13 Chain transfer polymerization Initiation R S R' Propagation R S etc R' R' J. Macrmol. Sc. Part A; 1999, 36, 51

14 Gold nanoparticles synthesis R 9 S n' + HAuCl 4 NaBH 4 ( agent (reducing a) b) c) d) J. Am. Chem. Soc.; 2005; 127; & Langmuir; 2007;23; 885

15 Endgroup contribution PMAAODT PMAADDT R PMAAHT SH R n' PMAAPentT SH PMAAPropT O R n' HO SHS n' PMAAMAT Langmuir; 2007;23; 885

16 Endgroup contribution Endgroup hydrophobicity C polymer C Au increasing PMAAODT M n =2980, M w =3480 PMAADDT Mn=2550, Mw=3491 PMAAHT Mn=2180, Mw=2550 PMAAPent Mn=2300, Mw=2670 PMAAProp Mn=1960, Mw=2340 PMAAMAT Mn=1780, Mw=2060 J. Am. Chem. Soc.; 2005; 127; & J. Langmuir; 2007;23; 885

17 Endgroup contribution Endgroup hydrophobicity C polymer C Au increasing PMAAODT M n =2980, M w =3480 PMAADDT Mn=2550, Mw=3491 PMAAHT Mn=2180, Mw=2550 PMAAPent Mn=2300, Mw=2670 PMAAProp Mn=1960, Mw=2340 PMAAMAT Mn=1780, Mw=2060 J. Am. Chem. Soc.; 2005; 127; & J. Langmuir; 2007;23; 885

18 Endgroup contribution Endgroup hydrophobicity C polymer C Au increasing PMAAODT M n =2980, M w =3480 PMAADDT Mn=2550, Mw=3491 PMAAHT Mn=2180, Mw=2550 PMAAPent Mn=2300, Mw=2670 PMAAProp Mn=1960, Mw=2340 PMAAMAT Mn=1780, Mw=2060 Langmuir; 2007;23; 885

19 Endgroup contribution Endgroup hydrophobicity C polymer C Au increasing PMAAODT M n =2980, M w =3480 PMAADDT Mn=2550, Mw=3491 PMAAHT Mn=2180, Mw=2550 PMAAPent Mn=2300, Mw=2670 PMAAProp Mn=1960, Mw=2340 PMAAMAT Mn=1780, Mw=2060 Langmuir; 2007;23; 885

20 Endgroup contribution Endgroup hydrophobicity C polymer C Au increasing PMAAODT M n =2980, M w =3480 PMAADDT Mn=2550, Mw=3491 PMAAHT Mn=2180, Mw=2550 PMAAPent Mn=2300, Mw=2670 PMAAProp Mn=1960, Mw=2340 PMAAMAT Mn=1780, Mw=2060 Langmuir; 2007;23; 885

21 Endgroup contribution Endgroup hydrophobicity C polymer C Au increasing PMAAODT M n =2980, M w =3480 PMAADDT Mn=2550, Mw=3491 PMAAHT Mn=2180, Mw=2550 PMAAPent Mn=2300, Mw=2670 PMAAProp Mn=1960, Mw=2340 PMAAMAT Mn=1780, Mw=2060 Langmuir; 2007;23; 885

22 Endgroup contribution Endgroup hydrophobicity C polymer C Au increasing PMAAODT M n =2980, M w =3480 PMAADDT Mn=2550, Mw=3491 PMAAHT Mn=2180, Mw=2550 PMAAPent Mn=2300, Mw=2670 PMAAProp Mn=1960, Mw=2340 PMAAMAT Mn=1780, Mw=2060 Langmuir; 2007;23; 885

23 What about thiol(s) containing endgroups? HS SH HS O SH O O O O O O HS O SH Langmuir; 2007;23; 885

24 What about thiol(s) containing endgroups? 20nm HS HOOC O S n O 50nm O O O O O HS O SH Langmuir; 2007;23; 885

25 «Small is beautiful» C polymer C Au increasing Absorbance Wavelength (nm)

26 «Small is beautiful» C polymer C Au increasing 1.7 nm

27 «Small is beautiful» C polymer C Au increasing 1.1 nm 1.7 nm

28 «Small is beautiful» C polymer C Au increasing 1.1 nm 1.1 nm 1.7 nm

29 «Small is beautiful» C polymer C Au increasing 1.1 nm 1.1 nm 1.1 nm 1.7 nm

30 «Small is beautiful» C polymer C Au increasing 1.1 nm 1.1 nm 1.1 nm 1.7 nm

31 Wavelength (nm) Wavelength (nm) Photophysical properties C polymer C Au increasing Excitation Emission Polymer concentration (mm) Intensity (a.u.) Intensity (a.u.) Polymer concentration (mm)

32 Are they really fluorescent? J. Am. Chem. Soc.; 2002; 125; 7780 & J. Am. Chem. Soc.; 2004; 126; 8358

33 Are they really fluorescent? The polymer is not fluorescent The polymer, after oxidation, is not fluorescent The polymer, after reduction, is not fluorescent The polymer, in the presence of HAuCl 4, is not fluorescent 200 Purification/control by size exclusion chromatography Concentration (ppm) Emission intensity (a.u.) S Au Retention time (min)

34 Occurenc es Core/shell structure 20 Core (HRTEM) Size (nm) Shell (???) 10 μm

35 Occurenc es Core/shell structure 20 Core (HRTEM) Size (nm) Shell (Fluorescence recovery after photobleaching)

36 Building a model

37 Conclusion A simple protocol for the preparation of nearmonodisperse gold nanoparticles in the small size regime below 5 nm has been developed. Polymer structures have been optimized to control the growth of gold nanoparticles, leading to a narrow size distribution. By varying systematically the polymer to gold ratio, the size of the nanoparticles can be finely tuned and a transition from nonfluorescent to fluorescent nanoparticles is observed. A combination of characterization techniques allow us to propose a theoratical model of the most fluorescent nanoparticle solution

38 Acknowledgements Supervision: Pr. Andrew I. Cooper Dr. Raphaël Lévy EP/C511794/1

39 Acknowledgements