ChemComm
Communication
3 S. Franz, S. Rammelt, D. Scharnweber and J. C. Simon, Biomaterials,
2011, 32, 6692.
4 B. D. Ratner and S. J. Bryant, Annu. Rev. Biomed. Eng., 2004, 6, 41.
5 R. A. Latour Jr, in Encyclopedia of Biomaterials and Biomedical
Engineering, Taylor & Francis, 2005, pp. 1–15.
6 C. J. Wilson, R. E. Clegg, D. I. Leavesley and M. J. Pearcy, Tissue Eng.,
2005, 11, 1.
7 M. R. Malone, J.-F. Masson, M. Barhnart, S. Beaudoin and
K. S. Booksh, Proc. SPIE-Int. Soc. Opt. Eng., 2005, 6007, 60070V.
8 S. Choi and J. Chae, J. Micromech. Microeng., 2010, 20, 075015.
9 B. Nilsson, K. N. Ekdahl, T. E. Mollnes and J. D. Lambris, Mol.
Immunol., 2007, 44, 82.
10 P. H. Kvist and H. E. Jensen, J. Diabetes Sci. Technol., 2007, 1, 746.
11 K. N. J. Stevens, Y. B. J. Aldenhoff, F. H. van der Veen, J. G. Maessen
and L. H. Koole, J. Biomed. Biotechnol., 2007, 2007, 29464.
12 S. Chen, L. Li, C. Zhao and J. Zheng, Polymer, 2010, 51, 5283.
13 I. Banerjee, R. C. Pangule and R. S. Kane, Adv. Mater., 2011,
23, 690.
14 P. Gong and D. W. Grainger, Methods Mol. Biol., 2007, 381, 59.
15 C. Zhao, L.-Y. Li, M.-M. Guo and J. Zheng, Chem. Pap., 2012, 66, 323.
16 E. Ostuni, R. G. Chapman, R. E. Holmlin, S. Takayama and
G. M. Whitesides, Langmuir, 2001, 17, 5605.
17 C. Blaszykowski, S. Sheikh and M. Thompson, Chem. Soc. Rev., 2012,
41, 5599.
18 S. Sheikh, D. Y. Yang, C. Blaszykowski and M. Thompson, Chem.
Commun., 2012, 48, 1305.
19 M. Thompson, S. M. Ballantyne, L.-E. Cheran, A. C. Stevenson and
C. R. Lowe, Analyst, 2003, 128, 1048.
20 S. M. Ballantyne and M. Thompson, Analyst, 2004, 129, 219.
21 A. Vasilescu, S. M. Ballantyne, L.-E. Cheran and M. Thompson,
Analyst, 2005, 130, 213.
22 S. Sheikh, J. C.-C. Sheng, C. Blaszykowski and M. Thompson, Chem.
Sci., 2010, 1, 271.
23 M. Thompson, S. Sheikh, J. C.-C. Sheng and C. Blaszykowski,
U. S. patent application publication, US 2011/0306771 A1, 2011.
24 S. Sheikh, C. Blaszykowski and M. Thompson, Talanta, 2011,
85, 816.
25 We note however that glass-coated (silicate) gold substrates,
on which our MEG-OH silane chemistry could in principle be
implemented, have recently been described for SPR analysis. See:
K. S. Phillips, J.-H. Han, M. Martinez, Z. Wang, D. Carter and
Q. Cheng, Anal. Chem., 2006, 78, 596.
extensive rinse-off (B+80 Hz in B60 min). With respect to bare
gold, a limited rinse-off phase likely indicates that species
responsible for fouling accumulate readily and quasi-irreversibly.
The fact that bare gold surfaces are heavily fouled (G c
100 ng cmÀ2) upon contact with serum, even diluted, has already
been documented on several occasions.31–35 In contrast, it
appears for the HS-MEG-OH case that the majority of serum
species adsorb in a reversible fashion involving transient inter-
action with the surface. The occurrence of a sequential ‘Vroman-
like’ process or/and stiffening events within the fouling layer also
constitute reasonable explanations.18
We note finally that whether or not bare gold surfaces are
submitted to the hydration treatment, DF values are not statisti-
cally different (À150 Æ 12 vs. À147 Æ 23 Hz) and TSM profiles
actually almost perfectly overlap (compare Fig. 2 and 3). This
observation may reflect an inherent inability for bare gold to
structure water molecules on its surface in a robust and thick
enough manner.36 This likely explains why gold presents a surface
that is fouled with facility by serum species in a manner akin to
quartz18 and other bare metal(loid) oxide surfaces.37–39 Conversely,
we attribute the behaviour observed for the hydrated HS-MEG-OH
adlayers to be the consequence of stronger and longer-range water
structuring properties. These are likely deeply rooted in a special
intrachain zone of hydration involving, synergistically, the internal
ether oxygen atoms and distal hydroxyl moieties.
In summary, we have herein elaborated on the antifouling
behaviour against serum of monoethylene glycol (MEG)
adlayers bearing distal hydroxyl groups. This MEG-OH surface
chemistry was successfully adapted from the hydroxylated sur-
face of quartz to the metal surface of gold using sulfhydryl-
based building block molecules. Dynamics of serum adsorption
was probed in a real-time and label-free manner using acoustic
wave physics and shown to be significantly altered when
compared to the results obtained for unmodified gold. Through
surface hydration experiments, empirical evidence was pro-
vided to support the widely proposed hypothesis that water
plays an important, if not pivotal, role in the antifouling of
surfaces constructed from short EG molecules. Integration of
this MEG-OH-type surface chemistry in biosensing platforms
for the serological detection of various disease-related biomar-
kers in clinical diagnostics is currently underway. We also aim
to generate biocompatible coatings on stainless steel and
plastic substrates for medical implants and equipment.
We thank the Natural Sciences and Engineering Research
Council of Canada for their support and Dr Peter Brodersen
from Surface Interface Ontario for XPS analysis. S.S. also grate-
fully acknowledges the Ontario Graduate Scholarship (OGS)
26 J. Homola, Chem. Rev., 2008, 108, 462.
´
27 M. Thompson, A. L. Kipling, W. C. Duncan-Hewitt, L. V. Rajakovic
ˇ
´
and B. A. Cavic-Vlasak, Analyst, 1991, 116, 881.
28 Thiol molecules have high affinity for metal surfaces, notably gold.
See: J. C. Love, L. A. Estroff, J. K. Kriebel, R. G. Nuzzo and
G. M. Whitesides, Chem. Rev., 2005, 105, 1103.
29 J.-M. Zheng, W.-C. Chin, E. Khijniak, E. Khijniak Jr. and
G. H. Pollack, Adv. Colloid Interface Sci., 2006, 127, 19.
30 X. Wang, J. S. Ellis, E.-L. Lyle, P. Sundaram and M. Thompson, Mol.
BioSyst., 2006, 2, 184.
31 L. M. Feller, S. Cerritelli, M. Textor, J. A. Hubbell and S. G. P. Tosatti,
Macromolecules, 2005, 38, 10503.
32 S. Lin, B. Zhang, M. J. Skoumal, B. Ramunno, X. Li, C. Wesdemiotis,
L. Liu and L. Jia, Biomacromolecules, 2011, 12, 2573.
´
33 C. Rodriguez-Emmenegger, O. Kylian, M. Houska, E. Brynda,
A. Artemenko, J. Kousal, A. B. Alles and H. Biederman, Biomacro-
molecules, 2011, 12, 1058.
34 G. Gunkel, M. Weinhart, T. Becherer, R. Haag and W. T. S. Huck,
Biomacromolecules, 2011, 12, 4169.
35 Q. Liu, A. Singh, R. Lalani and L. Liu, Biomacromolecules, 2012,
13, 1086.
36 N. Ikemiya and A. A. Gewirth, J. Am. Chem. Soc., 1997, 119, 9919.
37 A. R. Statz, A. E. Barron and P. B. Messersmith, Soft Matter, 2008,
4, 131.
´
program for financial support. C.A. thanks the Universite Pierre
et Marie Curie (Paris – France) for a travel grant.
¨ ¨
38 G. L. Kenausis, J. Voros, D. L. Elbert, N.-P. Huang, R. Hofer,
Notes and references
1 P. Thevenot, W. Hu and L. Tang, Curr. Top. Med. Chem., 2008, 8, 270.
L. Ruiz-Taylor, M. Textor, J. A. Hubbell and N. D. Spencer, J. Phys.
Chem. B, 2000, 104, 3298.
2 J. M. Anderson, A. Rodriguez and D. T. Chang, Semin. Immunol., 39 R. Konradi, B. Pidhatika, A. Mu¨hlebach and M. Textor, Langmuir,
2008, 20, 86.
2008, 24, 613.
c
This journal is The Royal Society of Chemistry 2013
468 Chem. Commun., 2013, 49, 466--468