The precise use of nanoparticles in technological applications requires control over their surface properties. This implies the ability to quantitatively describe, for example, molecular coatings in terms of their thickness, areal mass, or number of molecules. Here, the authors describe two different approaches to the measurement of these parameters by using gold nanoparticles ranging in diameter from 10 to 80 nm and coated with three different proteins: immunoglobulin G, bovine serum albumin, and a peptide. One approach utilizes ultraviolet–visible spectroscopy, dynamic light scattering, and differential centrifugal sedimentation to measure the protein shell refractive indices and thicknesses, from which the number of molecules in the protein shell can be derived. The other approach employs x-ray photoelectron spectroscopy to measure the thickness of the dry molecular coatings and also to derive the number of molecules in the protein shell. The authors demonstrate that the two approaches, although very different, produce consistent measurement results. This finding is important to extend the quantitative analysis of nanoparticle molecular coatings to a wide range of materials.

1.
C.
Minelli
,
S. B.
Lowe
, and
M. M.
Stevens
,
Small
6
,
2336
(
2010
).
2.
G.
Raschke
,
S.
Kowarik
,
T.
Franzl
,
C.
Sönnichsen
,
T. A.
Klar
,
J.
Feldmann
,
A.
Nichtl
, and
K.
Kürzinger
,
Nano Lett.
3
,
935
(
2003
).
3.
A.
Ito
,
M.
Shinkai
,
H.
Honda
, and
T.
Kobayashi
,
J. Biosci. Bioeng.
100
,
1
(
2005
).
4.
Y. F.
Wu
,
C. L.
Chen
, and
S. Q.
Liu
,
Anal. Chem.
81
,
1600
(
2009
).
5.
J.-M.
Nam
,
S. I.
Stoeva
, and
C. A.
Mirkin
,
J. Am. Chem. Soc.
126
,
5932
(
2004
).
6.
M. P.
Monopoli
,
C.
Aberg
,
A.
Salvati
, and
K. A.
Dawson
,
Nat. Nanotechnol.
7
,
779
(
2012
).
7.
S.
Tenzer
 et al,
Nat. Nanotechnol.
8
,
772
(
2013
).
8.
S. A.
Bhakta
,
E.
Evans
,
T. E.
Benavidez
, and
C. D.
Garcia
, “
Protein adsorption onto nanomaterials for the development of biosensors and analytical devices: A review
,”
Anal. Chim. Acta
(in press).
9.
R. A.
Petros
and
J. M.
DeSimone
,
Nat. Rev. Drug Discovery
9
,
615
(
2010
).
10.
N. C.
Bell
,
C.
Minelli
, and
A. G.
Shard
,
Anal. Methods
5
,
4591
(
2013
).
11.
C.
Minelli
,
R.
Garcia-Diez
,
A. E.
Sikora
,
C.
Gollwitzer
,
M.
Krumrey
, and
A. G.
Shard
,
Surf. Interface Anal.
46
,
663
(
2014
).
12.
N. C.
Bell
,
C.
Minelli
,
J.
Tompkins
,
M. M.
Stevens
, and
A. G.
Shard
,
Langmuir
28
,
10860
(
2012
).
13.
S.
Ray
and
A. G.
Shard
,
Anal. Chem.
83
,
8659
(
2011
).
14.
K. P.
Fears
,
T. D.
Clark
, and
D. Y.
Petrovykh
,
J. Am. Chem. Soc.
135
,
15040
(
2013
).
15.
S.
Techane
,
D. R.
Baer
, and
D. G.
Castner
,
Anal. Chem.
83
,
6704
(
2011
).
16.
S.
Techane
,
L.
Gamble
, and
D.
Castner
,
Biointerphases
6
,
98
(
2011
).
17.
A.
Rafati
,
R.
ter Veen
, and
D. G.
Castner
,
Surf. Interface Anal.
45
,
1737
(
2013
).
18.
A. G.
Shard
,
J. Phys. Chem. C
116
,
16806
(
2012
).
19.
R. R.
Naik
,
S. J.
Stringer
,
G.
Agarwal
,
S. E.
Jones
, and
M. O.
Stone
,
Nat. Mater.
1
,
169
(
2002
).
20.
C. F.
Bohren
and
D. R.
Huffman
,
Absorption and Scattering of Light by Small Particles
(
Wiley
,
New York
,
1983
).
21.
C.
Mätzler
,
Research Report No. 2002-08
, Institut für Angewandte Physik, University of Bern (
2002
), available at http://arrc.ou.edu/~rockee/NRA_2007_website/Mie-scattering-Matlab.pdf.
22.
J.
Teichroeb
, “
Selected experiments with proteins at solid-liquid interfaces
,” Ph.D. thesis (
University of Waterloo
,
Canada
,
2008
).
23.
See supplementary material at http://dx.doi.org/10.1116/1.4913566 for analysis of protein coatings on gold nanoparticles by XPS and liquid-based particle sizing techniques.
24.
M. P.
Seah
,
I. S.
Gilmore
, and
S. J.
Spencer
,
J. Electron Spectrosc. Relat. Phenom.
120
,
93
(
2001
).
25.
W.
Anderson
,
D.
Kozak
,
V. A.
Coleman
,
Å. K.
Jämting
, and
M.
Trau
,
J. Colloid Interface Sci.
405
,
322
(
2013
).
26.
A.
Laromaine
,
L.
Koh
,
M.
Murugesan
,
R. V.
Ulijn
, and
M. M.
Stevens
,
J. Am. Chem. Soc.
129
,
4156
(
2007
).
27.
S. H.
Brewer
,
W. R.
Glomm
,
M. C.
Johnson
,
M. K.
Knag
, and
S.
Franzen
,
Langmuir
21
,
9303
(
2005
).
28.
Ž.
Krpetić
,
A. M.
Davidson
,
M.
Volk
,
R.
Lévy
,
M.
Brust
, and
D. L.
Cooper
,
ACS Nano
7
,
8881
(
2013
).
29.
J. B.
Falabella
,
T. J.
Cho
,
D. C.
Ripple
,
V. A.
Hackley
, and
M. J.
Tarlov
,
Langmuir
26
,
12740
(
2010
).
30.
J.
Buijs
,
J. W. T.
Lichtenbelt
,
W.
Norde
, and
J.
Lyklema
,
Colloid Surf. B
5
,
11
(
1995
).
31.
K.
Kaur
and
J. A.
Forrest
,
Langmuir
28
,
2736
(
2011
).
32.
G.
Yohannes
,
S. K.
Wiedmer
,
M.
Elomaa
,
M.
Jussila
,
V.
Aseyev
, and
M.-L.
Riekkola
,
Anal. Chim. Acta
675
,
191
(
2010
).
33.
M. L.
Ferrer
,
R.
Duchowicz
,
B.
Carrasco
,
J. G.
de la Torre
, and
A. U.
Acuña
,
Biophys. J.
80
,
2422
(
2001
).
34.
S.
Goy-López
,
J.
Juárez
,
M.
Alatorre-Meda
,
E.
Casals
,
V. F.
Puntes
,
P.
Taboada
, and
V.
Mosquera
,
Langmuir
28
,
9113
(
2012
).
35.
L.
Pauling
and
R. B.
Corey
,
PNAS
37
,
729
(
1951
).
37.
J. A.
De Feijter
,
J.
Benjamins
, and
F. A.
Veer
,
Biopolymers
17
,
1759
(
1978
).
38.
H.
Zhao
,
P. H.
Brown
, and
P.
Schuck
,
Biophys. J.
100
,
2309
(
2011
).
39.
H.
Fischer
,
I.
Polikarpov
, and
A. F.
Craievich
,
Protein Sci.
13
,
2825
(
2004
).
40.
W. S. M.
Werner
,
M.
Chudzicki
,
W.
Smekal
, and
C. J.
Powell
,
Appl. Phys. Lett.
104
,
243106
(
2014
).

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