Supporting Information

Interfacial Properties and In Vitro Cytotoxic Effects of SurfaceModified Near Infrared Absorbing AuAu2S Nanoparticles

Mei Chee Tan,1 Jackie Y. Ying2, 3and Gan Moog Chow1, 4 *

1.Molecular Engineering of Biological and Chemical Systems, SingaporeMIT Alliance, 4 Engineering Drive 3, Singapore 117576;

2.Department of Chemical Engineering, MassachusettsInstitute of Technology, Cambridge, MA 02139-4307, USA;

3.Institute of Bioengineering and Nanotechnology, 31 Biopolis Way, The Nanos, Singapore 138669;

4.Department of Materials Science and Engineering, NationalUniversity of Singapore, 9 Engineering Drive 1, Singapore 117576

* To whom correspondence should be addressed: E-mail:

FigureS1. Optical properties of () uncoated, () MAAmodified, and () cisplatinloaded, MAAmodified NIR-absorbing nanoparticles.

FigureS2. Optical properties of () uncoated, () MPAmodified, and () cisplatinloaded, MPAmodified NIR-absorbing nanoparticles.

FigureS3. Optical properties of () uncoated, () MUAmodified, and () cisplatinloaded, MUAmodified NIR-absorbing nanoparticles.

FigureS4. Cytotoxicity of ()MAA, ()MPA, and ()MUA surfactants.

FigureS5. Cytotoxicity of cisplatin mixed with 0.15 μmol/ mL of ()MAA, ()MPA and ()MUA surfactants, and () native cisplatin.

FigureS6. 1HNMR spectra of cisplatin in 5% D2O aqueous solution.

FigureS7. 1H NMR spectra of Pt compounds released fromdrug-loadedMAAmodified particles in 5% D2O aqueous solution.

FigureS8. 1H NMR spectra of Pt compounds released from drug-loadedMPAmodified particlesin 5% D2O aqueous solution.

FigureS9. 1HNMR spectra of Pt compounds released from drug-loadedMUAmodified particles in 5% D2O aqueous solution.

TableS1. Assignment of vibrational modes for adsorbed MAA and MPA.

Wavenumber (cm-1) / Assignment (Mode)
2918 / a (CH2), antisymmetric stretching
1735 /  (C=O), stretching
1374 /  (CH2), wagging
1212 /  (CH2), twisting
1030 /  (CH2), rocking

TableS2. Assignment of vibrational modes for adsorbed MUA.

Wavenumber (cm-1) / Assignment (Mode)
2921 / a (CH2), antisymmetric stretching
2854 / s (CH2), symmetric stretching
1707 /  (C=O), stretching
1456 / s (CO2), symmetric stretching
1250 /  (CH2), twisting
1075 /  (CH2), rocking

TableS3. Estimated thickness of surfactant coatings from hydrodynamic diameters of surfacemodified nanoparticles dispersed in water.

Hydrodynamic Diameter(nm) / Thickness (nm)
Uncoated / 46 ± 5 / –
MAA-modified / 51 ± 4 / 2.5
MPA-modified / 50 ± 4 / 2.0
MUA-modified / 58 ± 9 / 6.0

TableS4. Assignment of possible combinations of Pt complexes to peaks in the mass spectrum of cisplatin.

Atomic Mass Unit / Assignment (Possible Combinations)
245 / Pt(NH3)2(OH)
265 / Pt(NH3)2(OH)2
282 / Pt(NH3)2(Cl)
299 / Pt(NH3)2(Cl)2
323 / Pt(NH3)(Cl)3
530 / [Pt(NH3)(OH)Cl]2, [Pt(NH3)2Cl]2or [Pt(NH3)2(OH)2]2
545 / [Pt(NH3)2(OH)2][Pt(NH3)2(Cl)(OH)]
566 / [Pt(NH3)2(OH)2][Pt(NH3)2(Cl)2]

TableS5. Assignment of possible combinations of complexes to peaks in the mass spectra of released Pt compounds.

Atomic Mass Unit / Assignment (Possible Combinations)
223 / Pt(N)2 or Pt(CH2)2
245 / Pt(NH3)2(OH)
277 / Pt(NH3)2(COO)
299 / Pt(NH3)2(Cl)2
365 / Pt(NH3)2(Cl)4
391 / PtAu
413 / PtAuC2

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