Supporting Information Synthesis of HEMA-LA.
(a)
a d
EDC/DMAP
+
b
CH2Cl2
f e
h g
c
i
m
j k
l
d+e c
(b)
f a
b
g+i m
CH2Cl2
j
l
k
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CHCl 3
7
6
5
4
3
2
1
ppm
Figure S1. (a) Synthesis of HEMA-LA monomer. (b) 1H NMR spectrum of HEMA-LA in CDCl3. Homopolymerization of HEMA-LA by ATRP. To a 10 mL roundbottom flask was added HEMA-LA (1.0 g, 3.1 mmol), PMDETA (10.4 mg, 0.06 mmol), and anisole (5 mL). The mixture was purged with N2(g) for 20 min, while stirring, at 0 °C. CuBr (8.6 mg, 0.06 mmol) was added quickly under N2, followed by bubbling with N2 for another 10 min. EBiB (17.7 mg, 0.06 mmol) was injected by syringe, and the mixture was transferred to a pre-heated oil-bath at 65 °C. At selected time points, 25 µL of the mixture was withdrawn into degassed syringe for 1H NMR and GPC analysis. Monomer conversion was calculated by integrating the vinyl protons at 6.12 ppm (CH2=C, monomer) and 5.59 ppm (CH2=C, monomer) against the methyl protons at 0.8-1.2 ppm (CH3, polymer). The polymerization was terminated by opening to air. The polymer was isolated as a yellow solid after precipitation into methanol and drying under vacuum.
Figure S2. (a) Homopolymerization of HEMA-LA via ATRP; (b) conversion vs. time data, and (c) evolution of molecular weight and PDI vs. time.
Example Procedure for Copolymerization of HEMA-LA and MPC by ATRP. To a 10 mL roundbottom flask was added EBiB (5.9 mg, 0.03 mmol), MPC (2.66 g, 9 mmol), and HEMA-LA (0.57 g, 1.8 mmol). A mixture of methanol and DMSO (6 mL, 1:1 v/v) was then added, and the resultant solution was purged with N2(g) for 30 min. CuBr (17 mg, 0.12 mmol) and bpy (75 mg, 0.48 mmol) were added quickly under N2(g). After purging with N2(g) for another 10 min, the mixture was stirred under N2 atmosphere at room temperature. Monomer conversion was monitored by 1H NMR spectroscopy, and the polymerization was terminated by purging air into the reaction mixture. The unreacted HEMA-LA was removed by precipitation into THF, and the precipitate was purified by passing through a silica gel plug to remove the MPC and catalyst. 1H NMR spectra of
pure polymer was recorded in methanol-d4 to measure LA loading. Average molecular weight and PDI of the polymers were measured by aqueous GPC.
(a)
d
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f'
f
h' g
j' H H k'
g e
f c
MeOH/H2O, 0 °C
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O
e g
S S
f N
h' g
i' SH
j'+k'
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l'
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SH
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d b+b'
(b) j'+e'
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c d b+b'
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c' +d'
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4.5
4.0
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3.0
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j'+k' f'+h' g'
2.0
90 60 30 0 -30 10
a+a'
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(d)
120
a+a'
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k'+f'+h' g'
Response
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5.5
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c
d
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NaBH4
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a' n O
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b
a
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c
DMSO/MeOH, RT
O
Br m O
n O
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CuBr/Bpy
+
a'
a
O
+
b'
b
O
1.5
1.0
ppm
P6
P6-R, after reduction
14
18
22
26
30
Minutes
Figure S3. (a) Copolymerization of MPC and HEMA-LA by ATRP; (b) 1H NMR spectrum of poly(MPC-co-LA); (c) 1H NMR spectrum of poly(MPC-co-DHLA); and (d) aqueous GPC traces of poly(MPC-co-LA), P6, and poly(MPC-co-DHLA), P6-R.
Table S1. Copolymer poly(MPC-co-LA) synthesized by ATRP and further reduced to poly(MPC-co-DHLA) Polymer NMPCa NHEMA-MAb N(CuBr:Bpy) c Rx time Conversiond Mn 50 200 200 200 200 300 300
P1 P2 P3 P4 P5 P6 P7
20 20 40 100 100 30 60
1:2 2:8 2:8 2:8 2:8 2:8 2:8
42 h 18 h 48 h 22 h 35 °C 22 h 18 h 44 h
68% 70% 65% 30% 55% 63% 52%
8k 24 k 17 k -36 k 26 k 14 k
PDI
LA (mol%)
Polymer
Mn
PDI
DHLA ( mol%)
1.56 1.53 1.53 -4.8 1.58 1.51
33% 16% 17% --11% 15%
P1-R P2-R P3-R P4-R P5-R P6-R P7-R
8k 23 k 17 k 8k 18 k 25 k 14 k
1.51 1.47 1.51 1.90 2.20 1.47 1.50
23% 10% 17% 36% 22% 10% 17%
a
: targeted degree of polymerization of MPC; b: targeted degree of polymerization of HEMA-LA; c: ratio of CuBr and bpy to initiator; d: Conversion measured by 1H NMR
Ln([M0]/[M])
1.0
0.5
0.0 0
2
4 6 Time (h)
8
10
Figure S4. ln ([Mo]/[M]) vs. time for RAFT polymerization of HEMA-LA.
13
C NMR characterization of poly(MPC-co-LA) and poly(MPC-co-DHLA)
Figure S5. 13C NMR spectrum of (a) poly(MPC-co-LA) and (b) poly(MPC-co-DHLA)
FTIR analysis of poly(MPC-co-DHLA) functionalized Au NR (PMPC-Au NR) The presence of poly(MPC-co-DHLA) ligand on poly(MPC) functionalized Au NR (PMPC-Au NR) was examined using attenuated total reflectance-fourier transform infrared spectroscopy (ATR-FTIR). The presence of carbonyl peak (1722 cm-1) confirmed the attachment of poly(MPC-co-DHLA) ligand on Au NR surface (Figure S6).
Figure S6. FTIR spectra of poly(MPC-co-DHLA) (black) and poly(MPC-co-DHLA) functionalized Au NR (red).
PC -A
u
N R PM
G -A u
N R PE
BA u
C TA
SA B
N R
1.1 1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 on ly
Relative BSA density
Protein fouling of functionalized Au NRs
Figure S7. Relative BSA density plot obtained by integrating migrated BSA protein band densities (using ImageJ software). The extent of protein fouling for CTAB-Au NR, PEGAu NR, and PMPC-Au NR samples (with BSA as control) was calculated from: (1 – relative BSA density) × 100%.
