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Electronic Supplementary Information

Controllable Self-Assembled Plasmonic Vesicle-Based Three-Dimensional SERS

Platform for Picomolar Detection of Hydrophobic Contaminants

Xiaolin Huang,a,b Yijing Liu,*b Jim Barr,c Jibin Song,b Zhimei He,b Yongmei Wang,c Zhihong

Nie,d Yonghua Xiong,*a and Xiaoyuan Chen*b

a State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang

330047, P. R. China; E-mail: yhxiongchen@163.com

b Laboratory of Molecular Imaging and Nanomedicine (LOMIN), National Institute of

Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health (NIH),

Bethesda, Maryland 20892, United States; E-mail: shawn.chen@nih.gov, yijing.liu@nih.gov

c Department of Chemistry, The University of Memphis, Memphis, Tennessee 38152, United

States

d Department of Chemistry and Biochemistry, University of Maryland, College Park,

Maryland 20742, United States

Electronic Supplementary Material (ESI) for Nanoscale.This journal is © The Royal Society of Chemistry 2018

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1. Calculation for enhancement factors (EFs) of SERS for nile red from different

assembled nanostructures.

The SERS EFs were calculated according to the previously reported method.1 In brief,

the EF of individual vesicles was determined by computing the ratio of SERS to normal

Raman scattering of Nile red using the following equation, EF = (ISERS × CNormal)/(INormal ×

CSERS), where ISERS and INormal are the Raman intensities at 591 cm-1 for various nanostructures

and pure nile red chloroform solution, CSERS and CNormal are the concentrations of nile red on

vesicles and in chloroform solution. CSERS was calculated by using this equation: CSERS =

(ATotal-AResidual)/V, where ATotal and AResidual are the total added amount of nile red during the

self-assembly and the residual amount of nile red in supernatant after centrifuging the

assemblies, respectively; V is the total reaction volume. The residual amounts of nile red in

supernatant after centrifuging the assemblies were calculated according to the standard curve

in Figure S9 (please see below).

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2. Calculation for estimated AuNP numbers per assembled vesicle.

The estimated AuNP numbers per assembled vesicle were determined according to the

following equation: N = 0.74* [4/3*π*(Rv3－(Rv－2*RG)3)]/( 4/3*π* RG

3), where Rv and RG

are the size of assembled vesicle and the size of original AuNPs, respectively, and the factor

0.74 accounts for the maximum packing that can be achieved for packing spheres. Take the

vesicle assembled from 80 nm coated with P3 as an example, the mean size of the formed

vesicle is around 550 ± 119 nm (n = 100). Here, we assumed the formed vesicle constituted of

single-layer AuNPs. Accordingly, the AuNP numbers on each vesicle were calculated as

follows:

The number of AuNPs was about 154 according to the following calculation:

Number=0.74*(4/3)*π*[(550/2)3－((550－2*80)/2)3)]/[(4/3)*π*(80/2)3]

=0.74*(2753－1953)/403 = 209*0.74=154.

Note: the AuNP numbers for other formed vesicles were also estimated using the same

method, and the detailed results were summarized in Table 1 in the main body of manuscript.

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Fig. S1 TEM images (A) and DLS analysis (b) of different sized AuNPs. 1, 2, and 3 represent AuNPs with size of 20, 50, and 80 nm, respectively.

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Fig. S2 UV-Vis spectra of different sized AuNPs before and after the conjugation of BCPs.

The sizes of AuNPs for self-assembly are 20 nm (A), 50 nm (B), and 80 nm (C), respectively.

P1, P2, and P3 represent BCPs with different polymer length (Table S1).

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Fig. S3 TEM images of various assembled nanostructures made from different sized AuNPs

(20, 50, and 80 nm) and BCPs with different length. The self-assembly of 20 nm AuNPs

tethered with BCPs with different molecular weight (Table S1): P1 (A), P2 (B), and P3 (C);

50 nm AuNPs tethered with P1 (D), P2 (E), and P3 (F); 80 nm AuNPs tethered with P1 (G),

P2 (H), and P3 (I). The insets represent the corresponding SEM images.

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Fig. S4 DLS analysis before and after the assembly of amphiphilic BCP-tethered AuNPs. The

size of AuNPs used in self-assembly are 20 nm (A), 50 nm (B), and 80 nm (C).

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Fig. S5 UV-Vis spectra before and after the assembly of amphiphilic BCP-tethered AuNPs

with different Au sizes: 20 nm (A), 50 nm (B), and 80 nm (C).

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Fig. S6 Raman intensity of nile red at 591 cm-1 before or after the dissociating plasmonic

vesicles with THF (A). The confirmation of the disassembly of assembled vesicles by DLS (B)

and UV-Vis spectra (C), respectively. The inset in Figure S6C indicates the color change of

solution before and after the disassembly. Result shows the color shifts from blue back to red

by dissociating the vesicles in THF. 1: with THF, and 2: without THF.

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Fig. S7 Molecular structures of three different PCBs, including PCB 7, PCB 77, and PCB 209

(A), and simultaneous detection for multiple PCBs from contaminated soil (B).

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Fig. S8 Standard curve of nile red performed by recording the absorbance at 530 nm against

different concentrations with Uv-Vis spectrophotometer.

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Table S1. The details for three amphiphilic BCPs (P1, P2, and P3)

Mn (kg/mol)Polymer type Compositions NMRP1 PEO45-b-PS50-SH 7.2P2 PEO45-b-PS450-SH 48.8P3 PEO45-b-PS900-SH 95.6

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Table S2. Comparison for our proposed 3D plasmonic vesicles and the previously reported

3D nanostructures for SERS application.

3Dnanostructures Compositions Target Detection

limit (g/mL)Detection

range (g/mL) EF Ref

Hybridnanostructures

AgNPs andZnO nanorods

Polychlorinated biphenyl 77 2.9×10-12 2.9×10-12 to 2.9×10-7 3.3×107 2

Rib-structures Cu butterfly wing

Rhodamine 6GCrystal violet 4.8×10-9 NR NR 3

Hybridnanostructures

AgNPs and TiO2 nanorods Malachite green 3.0×10-13 NR 4.3×105 4

Hybridnanostructures

AuNPs and carbon nanotubes Mercaptophenol 1.3×10-15 1.3×10-15 to 1.3×10-3 NR 5

Hydrophobic nanostructures Ag nanocubes Rhodamine 6G 4.8×10-19 5×10-13 to 5×10-10 1.0×1011 6

Multipetal flower

AuNPs andCopper flower Benzenethiol NR NR 1.9×107 7

Liquid marbles Ag nanocubes Methylene blue 3.2×10-11 3.2×10-8 to 3.2×10-5 5.0×108 8Polymer

nanotubes AgNPs Rhodamine 6G 4.8×10-11 4.8×10-11 to 4.8×10-7 4.0×107 9

Nanohump AgNPs andpolyacrylonitrile Rhodamine 6G 4.8×10-13 4.8×10-13 to 5×10-9 2.1×107 10

Colloidosomes Ag nanocubes Rhodamine 6G 4.8×10-10 5×10-10 to 5×10-7 2.0×106 11AuNPs/nickel

foamAuNPs and

nickel Pyrene 2.0×10-9 2×10-9 to 2×10-4 1.2×104 12

Ag colloidalsuperstructures AgNPs Crystal violet 4.1×10-11 4.1×10-11 to 4.1×10-9 1.9×107 13

Superlattice array Gold nanorods Malachite green 3.7×10-11 3.7×10-11 to 3.7×10-7 NR 14

3D aggregates AuNPs Rhodamine 6G 3.6×10-14 3.6×10-14 to 3.6×10-11 NR 15Vesicle AuNPs Nile red 1.0×10-12 1.0×10-12 to 1.0×10-6 1.9×108 this work

Note: NR is the abbreviation of “Not reported” in this Table.

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Table S3. Recoveries of Bap-spiked soil samples at four different concentrations of 10, 1, 0.1

and 0.01 ng/g from our proposed 3D SERS method and HPLC

3D SERS method (n = 6) HPLC (n = 6)Bap-spiked concentrations (ng/g) Bap recovered

(ng/g) CV (%) Bap recovered (ng/g) CV (%)

0.01 0.0093 ± 0.002 21.5 0.009 ± 0.0025 27.80.1 0.12 ± 0.02 16.7 0.105 ± 0.017 16.11 0.92 ± 0.093 10.1 1.03 ± 0.15 14.610 9.8 ± 1.2 12.2 9.4 ± 0.9 9.57

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