Protein Adsorption Switch Constructed by a Pillar[5]arene-Based Host-Guest Interaction

Article abstract of DOI:10.1002/chem.201504076

The interfacial properties of solid substrates are of importance for protein adsorption. Herein, we report a reversible protein adsorption switch based on the host-guest interaction of the butoxy pillar[5]arene and adipic acid. By the detector of the contact angle (CA), atomic force microscopy (AFM), and luminoscope on the silicon substrate, the intelligent protein switch exhibits excellent adsorptivity for BSA and switch performance by pH regulation.

Full text of DOI:10.1002/chem.201504076

DOI: 10.1002/chem.201504076
Full Paper
&
Host–Guest Systems |Hot Paper|
Protein Adsorption Switch Constructed by a Pillar[5]arene-Based
Host–Guest Interaction
[
a]
Xuan Xiao, Guanrong Nie, Xiaoyan Zhang, Demei Tian, and Haibing Li*
Abstract: The interfacial properties of solid substrates are of
importance for protein adsorption. Herein, we report a rever-
sible protein adsorption switch based on the host–guest in-
teraction of the butoxy pillar[5]arene and adipic acid. By the
detector of the contact angle (CA), atomic force microscopy
(AFM), and luminoscope on the silicon substrate, the intelli-
gent protein switch exhibits excellent adsorptivity for BSA
and switch performance by pH regulation.
Introduction
atoms in length by hydrophobic and electrostatic interac-
[
12]
tions.
In recent years, macromolecular adsorption behavior on solid
In addition, protein adsorption is a multifaceted process,
which is mainly affected by the nature of the hydrophobic in-
[
1]
surfaces, especially protein adsorption, has drawn much at-
tention because it plays a crucial role in medical, biological,
and physiological processes, and exhibits wide application in
[
13]
teractions and electrostatic effects. To realize the intelligent
protein adsorption, we designed a new pillar[5]arene with
[2]
[14]
the development of new biosensors, in immunological test-
butoxy functional groups (WP5) on the upper rim,
which
[3]
[4]
ing, and for drug delivery. Consequently, it is of interest to
design featured surfaces for protein adsorption. For example,
Wang et al., fabricated a gold surface with calix[4]arene deriva-
serves as the binding unit for proteins, whereas the cavity is
used for the reversible assembly and disassembly with surface
guests. To construct the intelligent switch, the surface was first
modified with the guest molecule adipic acid (AA). The WP5
solution was then added to the surface, which was modified
with AA under pH 3. The AA-WP5 host–guest complex sponta-
neously formed under those conditions, before protein adsorp-
tion was achieved by a hydrophobic interaction with the
[5]
tives that were designed to interact with proteins. Unfortu-
nately, this research demonstrated that the self-assembled sur-
face monolayer on the surfaces only realized irreversibly ab-
sorbed protein, and thus endowing these functional surfaces
for more intelligent protein adsorption is still a challenging
task. pH-responsive switches on a functional surface undergo
reversible changes in their properties when the solution is
changed to an appropriate pH. The protein adsorption on the
[
15]
butoxy groups of the WP5. Finally, the protein was desorbed
from the surface through an increase in solution pH to 11,
which resulted in the disassembly of the host–guest system.
[
6]
surface is an important property of a solid material, which
can be reversibly changed between hydrophobic and hydro-
philic states by regulation of pH. In this work, we extend sur-
face functionalization for protein adsorption using a reversible
host–guest interaction approach. Pillar[n]arenes (n=5,6) repre-
sent a new family of paracyclophanes and exhibit unique inclu-
Results and Discussion
The synthetic strategy for WP5 is depicted in Scheme 1. Hydro-
quinone 5.50 g (50 mmol) and potassium carbonate 13.80 g
(100 mmol) were stirred in refluxing acetonitrile for 0.5 h, and
then n-butyl bromide 13.70 g (100 mmol) was added. The mix-
ture was stirred at 1008C for 10 h, and the reaction liquid was
poured into ice water, and then neutralization of excess alkali
was carried out with dilute HCl to give the solid product. The
crude product was purified by recrystallization to give 1,4-di-
butoxy benzene as a white powder in 77.0% yield. Subse-
quently, 1,4-dibutoxy benzene 2.22 g (10 mmol) and parafor-
[
7]
sion properties. Pillararenes can selectively bind a range of
guests and provide a new platform for the construction of in-
[
8]
telligent switches. In recent years, many intelligent molecular
machines, based on a host–guest system, have been designed
[9]
[10]
to activate based on external stimuli, such as pH, electricity,
[
11]
or light.
Pillar[5]arene functionalized with decaamine can
strongly bind linear a,w-diacids that are six to 20 carbon
maldehyde (HCHO) 8.5 g (30 mmol) were stirred in refluxing
n
CHCl3 for 3 h under nitrogen protection and then FeCl3
(0.243 mL, 1.5 mmol) was added, and the crude product was
purified by column chromatography to give butoxy pillar[5]ar-
ene in 31.0% yield.
[
a] X. Xiao, G. Nie, X. Zhang, D. Tian, Prof. H. Li
Key Laboratory of Pesticide and Chemical Biology (CCNU)
Ministry of Education, College of Chemistry
Central China Normal University, Wuhan 430079 (P.R. China)
E-mail: lhbing@mail.ccnu.edu.cn
The target molecule, WP5, was synthesized by the strategy
depicted in Scheme S1 (Supporting Information) and was char-
Supporting information for this article is available on the WWW under
http://dx.doi.org/10.1002/chem.201504076.
1
13
acterized by H and C NMR spectroscopy (detailed in Figur-
Chem. Eur. J. 2016, 22, 941 – 945
941
ꢀ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Full Paper
create square pillars 20 mm high, 9 mm long and with
an interpillar spacing of 12 mm (Figure S5, Supporting
Information). Next, the surface was modified with 3-
aminopropyltrimethoxysilane (SiÀNH ), then AA was
2
chemically attached to the solid surface by a classical
EDC/NHS coupling reaction. Finally, the reversible sur-
Scheme 1. Synthesis of WP5.
face was assembled by addition of WP5 at pH 3 and
disassembled at pH 11. To verify the successful syn-
es S1 and S2, Supporting Information).To demonstrate that
WP5 is able to observe reversible assembly and disassembly
with AA by pH regulation, the process was followed by
thesis of the reversible surface, its performance was studied by
contact angle (CA) analysis. As shown in Figure 2a and Fig-
ure S7b (Supporting Information), the bare silicon wafer was
superhydrophilic, with the CA increasing to 25.1Æ2.08upon
1
H NMR spectroscopy. After AA had been added to a solution
of WP5, chemical shift changes for the proton resonances of
both WP5 and AA were observed. As shown in Figure 1 and
Figure S4 (Supporting Information), the methylene AA peak at
Figure 2. a) The WP5 and AA self-assembled host–guest system on a silicon
interface. b) Cycling CAs between basic and acid environments, showing six
cycles between the hydrophilic and hydrophobic states, confirming the pH-
responsive switching of the system.
Figure 1. a) Schematic representation of the WP5 and AA self-assembled
host–guest system. b) H NMR spectra showing: 1) free WP5, 2) WP5 and AA
1
(
pH 3), 3) the AA and WP5 after the addition of NaOH (pH 11), and 4) free
AA, which shows that WP5 can bind reversibly to AA and that the process is
reversible upon an increase in pH (6 mm, CDCl :CD OD=3:1, 400 MHz,
98 K).
3
3
2
the fixation of SiÀNH to the surface. Similarly, the CA contin-
2
ued to increase to 35.2Æ2.08 after chemical attachment of AA.
d=2.36 ppm shifts upfield to d=2.31 ppm, while the aromatic
peak of WP5 shifts downfield by d=0.02 ppm, which suggests
that AA binds within the cavity of WP5. When the pH value
was changed to 11, by the addition of NaOH, the chemical
shifts of the WP5 and AA peaks returned to their original
values, which is consistent with the disassembly of the WP5
and AA host–guest complex. Here, we defined that the assem-
bled state of the WP5 and the AA is “on” and the disassembled
state is “off”. To further demonstrate the host–guest complex
formation, the electrospray ionization mass spectrum is shown
in Figure S3, Supporting Information. The spectrum shows
a molecular-ion peak at m/z: 1339.300 that is exactly equal to
the calculated molecular mass for WP5, AA, and a sodium ion.
Based on the interaction between the WP5 and AA, a pH-re-
sponsive silicon surface was constructed (Figure S7a, Support-
ing Information). The silicon surface was prepared using
a plasma deep-etching technique of a flat silicon wafer to
Afterwards, the adipic acid modified surface (AA–Si) was im-
À3
mersed in a 10 m WP5 solution, at which point the CA in-
creased further to 148.9Æ2.08; a superhydrophobic state (de-
fined as “on”) that may be caused by the hydrophobic proper-
ties of WP5’s n-butyl. The result, therefore, suggests that WP5
bound successfully to the silicon surface (WP5–Si) through en-
capsulation of AA within its cavity. When the WP5–Si surface
was treated with a solution of pH 11, the CA of the surface re-
covered to 35.9Æ2.08; a hydrophilic state (defined as “off”),
which is consistent with disassembly of the WP5 AA host–
guest system. At the same time, we carried out SEM of
WP5ꢀAA complex before and after modification on the etch-
ing silicon surface (Figure S6, Supporting Information). Overall,
the results demonstrate that the switch is reversible and can
be controlled by adjusting solution pH. As shown in Figure 2b,
the switch can be turned off and on repeated times; six on/off
cycles were undertaken by changing solution pH.
Chem. Eur. J. 2016, 22, 941 – 945
www.chemeurj.org
942
ꢀ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Full Paper
Figure 3. AFM characterization showing substrata topographic images obtained from the BSA adsorbed onto the substrata. a) Native (AA-Si) and b) after
(
WP5-Si) functionalized at different times, which indicates the difference between the “on” and “off” states for BSA absorption with time. Images 350”350 nm
were first recorded under high load (z-range: 500 nm) of the same substrata.
We next confirmed the feasibility of the host–guest system
to act as a protein adsorption switch using fluorescence spec-
trophotometry. The functional silicon surface was placed in
a cuvette filled with the protein, bovine serum albumin (BSA)
for 1 h, before the fluorescence intensity was measured. As can
be seen in Figure S8a (Supporting Information), after immers-
ing the adipic acid modified surface (AA–Si) in the BSA solution
at pH 3 for 1 h, the fluorescence intensity for BSA adsorption
was slightly reduced compared with a bare silicon surface con-
trol under the same conditions. Next, the pillar[5]arene-modi-
fied silicon surface (WP5-Si) was added into a BSA solution for
cess on the silicon surface, the WP5-Si was immersed in a solu-
tion of BSA for 0, 10, 20, and 30 min, respectively, and then an-
alyzed by AFM and SEM. As shown in Figure 3b, the AFM
images show that the number of the granules increased,
which indicates that BSA adsorption increased over time. In
contrast, after the solution pH is increased to 11, there are no
observable granules by AFM, which indicates that BSA was not
adsorbed on the surface. These results were also confirmed by
SEM (Figure S11, Supporting Information). A significant differ-
ence was observed in the SEM images for BSA adsorption at
pH 3 and 11. The AA–Si surface does not significantly absorb
any BSA, and thus, the SEM image did not change with time.
However, the WP5-Si surface was observed to be covered with
an increasing number of lumps as time progressed, which indi-
cated that the quantity of BSA adsorbed onto the WP5-Si sur-
face increased with time. Furthermore, we also compared the
CA value as a function of time. The results show a remarkable
decrease of the CA as the WP5-Si adsorbed BSA over time (Fig-
ure S10, Supporting Information). In short, these experiments
demonstrate that the WP5-Si surface can adsorb BSA at pH 3,
and it releases from the surface at pH 11.
1
h, and the fluorescence was measured. The result was a sig-
nificant decrease in fluorescence intensity, which can be ex-
plained by a decrease in BSA concentration in solution as it is
adsorbed on the WP5-Si surface. When the solution pH is ad-
justed to 11, the fluorescence intensity nearly recovers to its in-
itial value, which suggests that the BSA has been released
from the silicon surface. We also investigated the repeatability
and reversibility properties of the BSA adsorption switch. In
a recycle experiment, the BSA adsorption switch was hardly af-
fected after six on/off cycles by alternating pH (Figure S9, Sup-
porting Information).
We hypothesize that the hydrophobic pocket of BSA can in-
teract with the hydrophobic alkyl chain of WP5 and the result-
ing interaction causes BSA to be absorbed from solution.
To further verify BSA adsorption onto the WP5-Si surface, ex-
periments to examine fluorescence kinetics, and analysis by
AFM and SEM, were carried out over various time periods. The
results for the fluorescence kinetics test over a period of 1 h
are shown in Figure S8b, Supporting Information. When the
AA–Si was soaked in BSA solution, the fluorescence change of
the solution versus time was close to a straight line compared
with the control, which showed that BSA was not adsorbed on
the AA–Si surface without WP5. In contrast, after the WP5-Si
surface was soaked in BSA solution, the fluorescence intensity
decreased gradually with the time and then remained constant
after about 30 min. To demonstrate the BSA adsorption pro-
[
16]
However, our results indicate that electrostatic interactions
do not contribute to BSA adsorption. This is because neither
the WP5 nor AA-Si, which has a pK of 3.8, are charged in a so-
a
lution of pH 3. Secondly, BSA adsorption on the WP5 surface is
driven by hydrophobic interactions. The WP5-Si surface, which
causes BSA adsorption, is superhydrophobic; this has been
demonstrated through tests. However, the AA–Si surface is hy-
drophilic, which means no BSA is absorbed in the absence of
WP5, which is consistent with our hypothesis that hydrophobic
interactions drive the absorption of protein (Figure 4).
Chem. Eur. J. 2016, 22, 941 – 945
www.chemeurj.org
943
ꢀ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Full Paper
Figure 4. A new protein adsorption switch successfully designed to turn “on” and “off” by pH adjustment based on a reversible host–guest system of WP5
and AA.
cleaned silicon wafer was soaked in 0.1m NaOH solution for 2 min
and was then put into the nitric acid solution of 0.1m for 10 min
Conclusion
to generate hydroxyl. Finally, the silicon wafer was washed with
distilled water and was then blown dry by nitrogen to reserve. The
A new protein adsorption, pH-driven switch was successfully
designed based on a reversible host–guest system of the
preprocessed silicon wafer was modified with the SiÀNH in a meth-
2
butoxy pillar[5]arene and adipic acid. Characterization by
anol solution of 5 wt% SiNH under reflux for 6 h at 608C. Then,
2
1
H NMR spectroscopy, fluorescence, ESI-MS, AFM, and SEM,
the silicon chip was washed with methanol to remove the unreact-
ed SiÀNH . Subsequently, the adipic acid was fixed on the SiÀNH -
showed that the WP5 surface exhibited not only favorable ad-
sorption of BSA, but that the BSA adsorption could be
switched by adjusting the pH. As the protein absorption can
be monitored using fluorescence spectrophotometry, our
system many have wide application in the production of new
biosensors, in immunological tests, and in drug delivery.
2
2
modified silicon wafer by a classical EDC/NHS coupling reaction.
During the process, amino silane-modified wafers continue to be
À3
immersed in the methanol solution containing10 m AA, EDC
À3
À3
(
10 m), and five fluorine phenol (10 m) under 08C for 24 h. After
this time, the silicon wafer was washed with methanol and blown
dry by nitrogen. Ultimately, the butoxy pillar[5]arene was self-as-
sembled in chloroform solution.
Experimental Section
Fluorescent assay
Synthetic method for butoxy pillar[5]arene
To prove good pH-responsive properties of the host–guest system,
fluorescent spectroscopic studies were carried out. The fluores-
The synthetic strategy for WP5 is depicted in Scheme 1. Hydroqui-
none 5.50 g (50 mmol) and potassium carbonate 13.80 g
cence kinetics experiment was measured in the BSA solution (5”
(
100 mmol) were stirred in refluxing acetonitrile for 0.5 h, and then
À5
1
0
m) in which the functioned surface was put. After the dynamic
n-butyl bromide 13.70 g (100 mmol) was added. The mixture was
stirred at 1008C for 10 h. After the reaction was finished, the reac-
tion liquid was poured into ice water and then dilute HCl was
added to neutralize excess alkali to gain solid product. The crude
product was purified by recrystallization to give 1,4-dibutoxy ben-
zene as a white powder in 77.0% yield. Subsequently, 1,4-dibutoxy
benzene 2.22 g (10 mmol) and paraformaldehyde (HCHO)n 8.5 g
adsorption, the fluorescence intensity for the residual solution was
put into effect. All the above fluorescent experiments were con-
ducted by using the Agilent Cary Eclipse fluorescence system (Aus-
tralia).
Contact angles measurement
(
30 mmol) were added and stirred while refluxing in CHCl for 3 h
3
The contact angles were measured using an OCA 20 contact angle
system (Dataphysics, Germany), at 258C. After the modification of
the silicon surface, the functional silicon surface was washed with
under nitrogen protection, and then FeCl3 0.243 mL (1.5 mmol)
was added. The crude product was purified by column chromatog-
1
raphy to give butoxy pillar[5]arene in 31% yield. H NMR (CDCl ,
3
the corresponding solvent, and was then blown dry by N before
6
00 MHz, 298 K): d=0.96–0.98 (t, 30H, CH ), 1.51–1.55 (m, 20H,
2
3
measuring the CA after every step of the modification.
CH ), 1.75–1.79 (m, 20H, CH ), 3.75 (s,10H, CH -bridge), 3.84–3.86
2
2
2
1
3
(
t, 20H, O-CH ), 6.83 ppm (s, 10H, Ar-H); C NMR (150 MHz, CDCl3):
2
d=13.04 (CH ), 18.52 (CH ), 31.06 (CH ), 36.6 (CH -bridge), 66.90
3
2
2
2
(
OÀCH ), 113.77 (ArÀH), 127.09 (ArÀO), 149.77 ppm (ArÀO); MS: m/
2
Acknowledgements
+
z: calcd for 1182.81; found: 1183.91 [M+H ]; elemental analysis
(
%) (found: C 77.28, H 9.26; WP5 requires C 77.12, H 9.37).
This work was financially supported by the National Natural
Science Foundation of China (21572076, 21372092), Natural
Science Foundation of Hubei Province (2013CFA112,
2014CFB246), Wuhan Scientific and Technological Projects
(2015020101010079), and self-determined research funds of
Modification process
The etched silicon was soaked in chromic acid lotion for about 2 h,
to remove organic matter on the silicon surface. After that, the
Chem. Eur. J. 2016, 22, 941 – 945
www.chemeurj.org
944
ꢀ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Full Paper
CCNU from the colleges’ basic research and operation of MOE
CCNU15KFY005).
[6] a) Y. Kong, F. Xia, M. H. Zhang, X. Hou, Z. Y. Liu, J. Zhai, L. Jiang, ACS
Appl. Mater. Interfaces 2013, 5, 7931; b) X. Hou, W. Guo, L. Jiang, Chem.
Soc. Rev. 2011, 40, 2385.
(
[
7] a) J. Cao, Y. Shang, B. Qi, X. Z. Sun, L. Zhang, H. W. Liu, H. B. Zhang, X. H.
Zhou, RSC Adv. 2015, 5, 9993; b) T. Ogoshi, T. Yamagishi, Chem.
Commun. 2014, 50, 4776; c) Y. Y. Yuan, C. Q. Mao, X. J. Du, J. Z. Du, F.
Wang, J. Wang, Adv. Mater. 2012, 24, 5476.
Keywords: bovine serum albumin · host–guest systems · pH
reversible switch · pillar[5]arene · proteins
[
[
8] N. L. Strutt, H. Zhang, S. T. Schneebeli, J. F. Stoddart, Acc. Chem. Res.
[
1] a) J. D. Müller, M. Amrein, A. Engel, J. Struct. Biol. 1997, 119, 172; b) A.
Vinu, Carsten. Streb, V. Murugesan, M. Hartmann, J. Phys. Chem. B 2003,
2014, 47, 2631.
9] a) Q. P. Duan, Y. Cao, Y. Li, X. Y. Hu, T. X. Xiao, C. Lin, Y. Pan, L. Y. Wang, J.
Am. Chem. Soc. 2013, 135, 10542; b) S. Angelos, Y. W. Yang, K. Patel, J. F.
Stoddart, J. I. Zink, Angew. Chem. Int. Ed. 2008, 47, 2222; Angew. Chem.
107, 8297; c) H. X. Zhou, G. Rivas, A. P. Minton, Annu. Rev. Biophys. 2008,
37, 375; d) I. Banerjee, R. C. Pangule, R. S. Kane, Adv. Mater. 2011, 23,
690; e) Q. Wei, T. Becherer, P. M. Noeske, I. Grunwald, R. Haag, Adv.
2
008, 120, 2254.
10] a) E. Gallicchio, M. Lapelosa, R. M. Levy, J. Chem. Theory Comput. 2010,
, 2961; b) J. E. Elenewski, J. C. Hackett, J. Phys. Chem. B 2010, 114,
1315.
11] a) X. Y. Zhang, H. Y. Zhao, D. M. Tian, H. T. Deng, H. B. Li, Chem. Eur. J.
Mater. 2014, 26, 2688; f) V. O. Kollath, F. Van den Broeck, K. Fehr, J. C.
Martins, J. Luyten, K. Traina, S. Mullens, R. Cloots, Chem. Eur. J. 2015, 21,
[
[
[
6
1
1
2
0497; g) X. Hou, Y. H. Hu, A. Grinthal, M. Khan, J. Aizenberg, Nature
015, 519, 70.
[
2] a) K. E. Sapsford, F. S. Ligler, Biosens. Bioelectron. 2004, 19, 1045; b) E. S.
Jeng, P. W. Barone, J. D. Nelson, M. S. Strano, Small 2007, 3, 1602; c) Q.
Wei, T. Becherer, S. Angioletti-Uberti, J. Dzubiella, C. Wischke, A. T. Neffe,
A. Lendlein, M. Ballauff, R. Haag, Angew. Chem. Int. Ed. 2014, 53, 8004;
Angew. Chem. 2014, 126, 8138; d) K. Takasu, K. Kushiro, K. Hayashi, Y.
Iwasakic, S. Inouec, E. Tamechikad, M. Takaia, Sens. Actuators B 2015,
2
2
014, 20, 9367; b) G. Pouliquen, C. Amiel, C. Tribet, J. Phys. Chem. B
007, 111, 5587.
12] a) X. B. Hu, L. Chen, W. Si, Y. H. Yu, J. L. Hou, Chem. Commun. 2011, 47,
694; b) A. C. McUmber, T. W. Randolph, D. K. Schwartz, J. Phys. Chem.
Lett. 2015, 6, 2583; c) X. Hou, H. Dong, D. B. Zhu, L. Jiang, Small 2010,
, 361.
13] a) K. L. Prime, G. M. Whitesides, Science 1991, 252, 1164; b) V. Silin, H.
Weetall, D. J. Vanderah, J. Colloid Interface Sci. 1997, 185, 94; c) R. D.
Tilton, C. R. Robertson, A. P. Gast, Langmuir 1991, 7, 2710; d) M. J. W.
Ludden, A. Mulder, R. TampØ, D. N. Reinhoudt, J. Huskens, Angew. Chem.
Int. Ed. 2007, 46, 4104; Angew. Chem. 2007, 119, 4182.
4
6
4
28; e) X. Hou, L. Jiang, ACS Nano 2009, 3, 3339.
[
[
[
3] a) J. M. Peula-García, J. A. Molina-Bolivar, J. Velasco, A. Rojas, F. Galisteo-
Gonzalez, J. Colloid Interface Sci. 2002, 245, 230; b) H. Dong, R. Nie, X.
Hou, P. Wang, J. Yue, L. Jiang, Chem. Commun. 2011, 47, 3102; c) X. H.
Cheng, H. E. Canavan, D. J. Graham, D. G. Castner, B. D. Ratner, Biointer-
phases 2006, 1, 61; d) W. H. Hu, Y. S. Liu, T. Chen, Y. Liu, C. M. Li, Adv.
Mater. 2015, 27, 181.
4] a) A. S. Zahr, D. V. Melgardt, M. V. Pishko, Langmuir 2005, 21, 403;
b) C. C. Lin, A. T. Metters, Biomacromolecules 2008, 9, 789; c) J. Zhang,
W. Sun, L. Bergman, J. M. Roseholm, M. Linden, G. J. Wu, H. Xu, H. C. Gu,
Mater. Lett. 2012, 67, 379; d) X. Hou, Y. J. Liu, H. Dong, F. Yang, L. Li, L.
Jiang, Adv. Mater. 2010, 22, 2440; e) G. C. Yu, Y. J. Ma, C. Y. Han, Y. Yao,
G. P. Tang, Z. W. Mao, C. Y. Gao, F. H. Huang, J. Am. Chem. Soc. 2013,
[
[
14] M. Xue, Y. Yang, X. D. Chi, Z. B. Zhang, F. H. Huang, Acc. Chem. Res.
2012, 45, 1294.
15] a) K. Farkas, A. Varsani, L. P. Pang, Food Environ. Virol. 2014, 7, 261; b) S.
Mauri, M. Volk, S. Byard, H. Berchtold, H. Arnolds, Langmuir 2015, 31,
8892.
[
16] a) A. Rubinstein, S. Sherman, Biopolymers 2007, 87, 149; b) M. Van
der Veen, W. Norde, M. C. Stuart, Colloids Surf. B 2004, 35, 33.
1
35, 10310.
[
5] a) H. Chen, F. Liu, F. Qi, K. Koh, K. Wang, Int. J. Mol. Sci. 2014, 15, 5496;
b) X. Hou, H. C. Zhang, L. Jiang, Angew. Chem. Int. Ed. 2012, 51, 5296;
Angew. Chem. 2012, 124, 5390.
Received: October 11, 2015
Published online on December 3, 2015
Chem. Eur. J. 2016, 22, 941 – 945
www.chemeurj.org
945
ꢀ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim