Supporting Information
Non-leaching antimicrobial surfaces through polydopamine
bio-inspired coating of quaternary ammonium salts or an
ultrashort antimicrobial lipopeptide
Tal Shalev,a Anna Gopin,a Michael Bauer,b Robert W. Starkb,c,d
and Shai
Rahimipour*a
a Department of Chemistry, Bar-Ilan University, Ramat-Gan 52900,
Israel. E-mail:
[email protected] b Center for Nanoscience CeNS,
Ludwig-Maximilians-Universität Mu !nchen, Mu !nchen 80799,
Germany; c Department of Materials and Geosciences, Technische
Universität Darmstadt,
Darmstadt 64287, Germany; d Center of Smart Interfaces,
Technische Universität Darmstadt,
Darmstadt 64287, Germany
Electronic Supplementary Material (ESI) for Journal of Materials
ChemistryThis journal is © The Royal Society of Chemistry 2012
Peptides Synthesis
Coupling was carried out in N-methyl-2-pyrrolidone (NMP), and
2-(1H-benzotriazol-1-
yl)-1,1,3,3-tetramethyluronium hexafluorophosphate (HBTU) was
used as the coupling
agent. Peptides were labeled with 4-nitrobenzo-1,2,5-oxadiazole
(NBD) as a fluorescent
probe, by reacting the N-terminal of the anchored peptides with
NBD-Cl. The peptides
were cleaved from the resin and deprotected by a mixture of
trifluoroacetic acid (TFA) :
triisopropylsilane (TIS) : H2O (95 : 2.5 : 2.5), while peptides
containing a cysteine
residue were de-protected and cleaved from the resin by a TFA :
TIS : H2O :
ethanedithiol (94 : 2.5 : 1 : 2.5) solution and purified to
homogeneity by RP-HPLC. The
pure peptides were analyzed by mass spectrometry using a
MALDI-TOF/TOF or ESI
mass spectrometer.
Synthesis of fluorescent probes (1, 2). The probes were
synthesized on Rink amide
resin. For the synthesis of the probe 1, Fmoc-Cys(Trt)-OH and
Fmoc-11-amino-
undecanoic acid were sequentially coupled to the resin by the
HBTU/DIPEA method.
Following the deprotection of the last Fmoc group,
4-chloro-7-nitrobenzofurazan (NBD-
Cl, 2 eq. in 2 ml DMF) and DIPEA (4 eq.) were added to the resin
and the mixture was
shaked for 24 h at 37ºC. The crude peptide was cleaved from the
resin and purified by
HPLC. MS(ESI): m/z calcd for: C20H30N6O5S [MH]+: 466; found 466,
489 [M+Na]+.
For the preparation of probe 2, Fmoc-Lys(Boc)-OH was coupled to
the Rink amide resin
by the HBTU/DIPEA method.
Fmoc-14-amino-5-oxo-3,9,12-trioxa-6-azatetradecan-1-
oic acid was then coupled twice to the resin followed by
introduction of a NBD group to
the terminal amine. The crude peptide was then analyzed and
purified to homogeneity by
preparative HPLC. MS: m/z calcd for: C32H53N10O14 [M+ H]+:
801.4; found: 801, 823
[M+Na]+.
Synthesis of quaternary ammonium salts (3, 4). Fmoc-Cys(Trt)-OH
(in case of 3) or Fmoc-Lys(Boc)-OH (in case of 4) were attached to
the Rink amine resin followed by
the coupling of Fmoc-11-aminoundecanoic acid, using the
HBTU/DIPEA method. Next,
4-(Dimethylamino) butyric Acid (1eq. in 2 mL DMF) was coupled to
the terminal amine,
using the mixture of HOBT\DIC\DMAP (1.1:1.1:0.1) and DIPEA (4
eq.) at 37°C for 3
Electronic Supplementary Material (ESI) for Journal of Materials
ChemistryThis journal is © The Royal Society of Chemistry 2012
hours. One-bromodecane (4 eq. in DMF) and DIPEA (4 eq.) were
then added to the resin
and mixed for 96 hours. The crude peptides were cleaved and
purified as detailed above. 1H-NMR 3: (300 MHz, CDCl3) δ(ppm) 0.87
(t, 3H, J=6.5, H-C1), 1.39-1.22 (bs, 28H, H-
C2, H-C3, H-C4, H-C5, H-C6, H-C7, H-C8, H-C20, H-C21, H-C22,
H-C23, H-C24, H-
C25), 1.42 (bs, 2H, H-C26), 1.66 (bs, 2H, H-C9), 2.29-2.1 (m,
4H, H-C14, H-C27), 2.43
(t, 2H, J=7.45 Hz, H-C15), 3.05 (s, 6H, H-C11, H-C12), 3.4-3.17
(m, 8H, H-C10, H-C13,
H-C18, H-C33), 4.78 (dd, 1H, J=12.22Hz, J=5.88Hz, H-C30), 7.15
(bs, 2H, H-N32), 7.94
(bs, 2H, H-N17, H-N27) 13C-NMR 3: (500 MHz, DMSO-d6) δ(ppm)
13.93 (C1), 22.08 (C2), 26.45 (C33), 31.27
(C3), 51.68 (C11, C12), 55.74 (C30), 170.33 (C28), 172.04 (C16),
172.38 (C31).
HR-MS (MALDI-TOF-TOF) 3: m/z calcd for: C30H61N4O3S, [M+ H]+:
557.446; found:
557.4459;
1H-NMR 4: (300MHz,CDCl3), δ(ppm) 0.87 (t, 3H, J=6.5, H-C1),
1.39-1.22 (bs, 28H, H-
C2, H-C3, H-C4, H-C5, H-C6, H-C7, H-C8, H-C20, H-C21, H-C22,
H-C23, H-C24, H-
25), 1.42 (m, 4H, H-C26, H-C35), 1.66 (bs, 4H, H-C9, H-C33),
2.08 (p, 2H, H-C14,
J=7.82Hz), 2.43 (t, 2H, H-C15, J=7.45), 2.68 (m, 2H, H-C36),
3.04 (s, 6H, H-C11,H-
C12), 3.4-3.17 (m, 6H, H-C10, H-C13, H-C18), 4.47 (dd, 1H,
H-C30, J=11.97 Hz,
J=4.93 Hz), 5.28 (d, 2H, H-C37, J=0.33 Hz), 7.15 (bs, 2H,
H-N32), 7.94 (bs, 2H, H-N17,
H-N27).
HR-MS (MALDI-TOF-TOF) 4: m/z calcd for: C33H68N5O3, [M+ H]+:
582.531; found:
582.5317.
Electronic Supplementary Material (ESI) for Journal of Materials
ChemistryThis journal is © The Royal Society of Chemistry 2012