Supporting Information. Two Are Better than One: Halloysite Nanotubes-Supported Surface Imprinted

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1 Supporting Information Two Are Better than One: Halloysite Nanotubes-Supported Surface Imprinted Nanoparticles Using Synergy of Metal Chelating and Low pka Boronic Acid Monomers for Highly Specific Luteolin Binding under Neutral Condition Shucheng Liu, Jinxin Liu, Jianming Pan,,, Jialu Luo, Xiangheng Niu,, Tao Zhang, Fengxian Qiu School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang , China Department of Chemistry, Stanford University, Stanford, California, 94305, USA * or (J. Pan); (X. Niu) S-1

2 The details of the reagents and equipments. Luteolin (LTL) was provided by Kan Sheng Co., Ltd (Shangxi, China). HNTs were collected from by Zhengzhou Jinyangguang Chinaware Co., Ltd. (Henan, China). Dopamine hydrochloride (DA), triethylamine (TEA), propidiumiodide (PI), 4,6-diamidino-2-phenylindole (DAPI), anisole, alizarin red S (ARS), α-bromoisobutyryl bromide (BIBB, 98%), hydroquinone (HDQ), quercetin (QRT), 4-chloro-3-hydroxytoluene (4C3H), ethanol, paraformaldehyde, phosphoric acid, tetrahydrofuran (THF), CuCl 2, N,N,N,N,N -pentamethyl diethylenetriamine (PMDETA, 98%), N,N-dimethylformamide (DMF), vinyl imidazole (VLD), L-ascorbic acid, 10% Pd/C (Degussa type E101 NE/W), thionyl chloride, triethylamine ethanol, acryloy chloride, and Zn(NO 3 ) 2 6H 2 O were purchased from Sinopharm Chemical Reagent Co., Ltd. (Shanghai, China). 4-Carboxy-3-fluorophenyl boronic acid was purchased from Wako Pure Chemical Industries, Ltd. (Osaka, Japan). XPS spectra were performed on a thermo ESCALAB 250 with Al Ka radiation at y = 901 for the X-ray sources, and the binding energies were calibrated using the C1s peak at ev. High efficiency liquid phase (HPLC) analysis was carried out on an Agilent System (Agilent, 1200, Germany) equipped with a UV-vis detector. Infrared spectra ( cm -1 ) were recorded on a Nicolet NEXUS-470 FTIR apparatus (USA). Raman spectra was recorded in the range of cm -1 at ambient temperature using a WITEC Spectra Pro 2300I spectrometer equipped with an Ar-ion laser, which provided a laser beam of 514 nm wavelength. 1 H Nuclear Magnetic S-2

3 Resonance Spectroscopy ( 1 H NMR) was performed with AVANCEII at 400 MHz (Bruker, Switzerland). The specific surface area was detected by Brunauer-Emmett-Teller (BET) method. Contact angle measurement of polymers was performed on Optical Contact Angle Measuring Device (KSV CM200). The morphology of the various materials was characterized by transmission scanning electron microscopy (TEM, JEM-2100). The ζ potential and dynamic light scattering (DLS) of aqueous colloidal particles was measured using a Malvern Zetasizer Nano ZS90. TGA analysis for powder samples (approximately 10 mg) was performed under a nitrogen atmosphere ranging from 25 to 1000 along with a heating rate of 5.0 min -1 by using a Diamond TG/DTA Instruments (Perkin-Elmer, U.S.A.). Laser scanning confocal microscopy (LSCM) images were observed using a TCS SP5 II confocal microscope (Leica, Germany) with a 476 nm solid state laser light source. Boronate affinity ability was checked via the interaction between cis-diol containing fluorescent dye(i.e. ARS, 0.05 mm)and DM-MIPs. For comparison, DM-MIPs were mixed with ARS at ph=8.5, 7.0, and ph=4.0, and then the collected nanoparticles were exhibited through fluorescence. 20 Energy dispersive spectrometer (EDS) was detected via field emission scanning electron microscopy (SEM, JSM-7100F). The concentration of Zn 2+ was determined by TAS-986 flame atomic absorption spectrometer (FAAS) (Beijing, China). The details of the adsorption experiments. To test the adsorption kinetics, 10 mg adsorbent (i.e. HNTs-PDA-PVLD-Zn(II), MIPs-A, DM-MIPs, and DM-NIPs, S-3

4 respectively) was added to 10 ml LTL testing solutions with the initial concentration of 25 mg L -1. The mixture was placed at water bath (298 K) for predetermined different time intervals (10, 30, 60, 120, 180, 360, 720 min). Then the concentration of LTL in the filtrate was detected by UV-visible spectrophotometry at nm. Then the adsorption amount at time t (Q t, mg g -1 ) of LTL was calculated by Eq. (1). = ( ) (1) where C 0 and C t (mg ml -1 ) represent the concentrations of LTL at initial time and at different contact time t, respectively. V is the volume of LTL solution, and m is the mass of adsorbent. To study the adsorption isotherm, 10 mg adsorbent (i.e. HNTs-PDA-PVLD-Zn(II), MIPs-A, and DM-MIPs and DM-NIPs, respectively) was added 10 ml LTL testing solutions with different concentrations (15, 20, 25, 30, 35, 40 mg L -1 ). After incubating for 3.0 h at 298 K, the UV-visible spectrophotometry was also used for the determination of LTL. The equilibrium adsorption amount (Q e, mg g -1 ) of LTL was calculated by Eq. (2). = ( ) (2) where C 0 and C e (mg ml -1 ) represent the concentrations of LTL at initial time and equilibrium, respectively. The details of the binding specificity experiment. 10 mg of adsorbent was added into 10 ml centrifuge tubes, each of which contained 10 ml single solution with 25 mg L -1 of LTL, 4C3H, QRT and HDQ, respectively. After batch mode binding S-4

5 experiments at 298 K, the concentrations of LTL, 4C3H, QRT and HDQ in the filtrate were determined by UV-visible spectrophotometry at their corresponding wavelength (349 nm, 228 nm, 374 nm and 292 nm, respectively). To test the competitive adsorption, the binary solutions (LTL/HDQ, LTL/QRT, LTL/4C3H, 25 mg L -1 /25 mg L -1 ) were considered in the binding experiments. The residual concentrations of LTL were determined by HPLC at 310 nm. The injection loop volume was 20 µl, and the mobile phase was consisted of methanol and deionized water with a volume ratio of 70: 30. The flow rate was 0.65 ml min -1 and the column temperature was 25 C. The details of the regeneration experiment. Desorption and recyclability experiments of the adsorbent were carried out to check the regeneration ability of the hybrid DM-MIPs. Briefly, the captured samples were dispersed in 5.0 ml ( 2) of methanol/acetic acid (v:v, 7:3), and the suspension were then stirred for 120 min. After washing for twice with deionized water, DM-MIPs nanoparticles were chelated with Zn 2+ for another 5.0 min and used for the separation experiment again. The concentration of Zn 2+ in the elution was tested via FAAS, and then the released amount of Zn 2+ from DM-MIPs was calculated. This adsorption-desorption step was repeated at least six times to determine adsorption amount of DM-MIPs for LTL. Equations for describing kinetics performances. pseudo-first-order rate equation and pseudo-second-order rate equation are listed as Eq. (1) and Eq. (2), respectively. S-5

6 = (1) = (2) where Q t (mg g -1 ) is the adsorption amount for LTL at time t (min). k 1 (L min -1 ) and k 2 (mg g -1 min -1 ) are the rate constants of the pseudo-first and pseudo-second models, respectively. h and t 1/2 (min) can be calculated form the Eq. (3) and Eq. (4). h= (3) / = (4) Equations for describing equilibrium performances. Langmuir and Freundlich adsorption isotherms are presented in Eq. (5) and Eq. (6), respectively. = (5) = / (6) where C e (mg L -1 ) is the equilibrium concentration of LTL (mg L -1 ) in the solution, Q e (mg g -1 ) is the amount of LTL adsorbed at the equilibrium. Q m (mg g -1 ) is the maximum adsorption capacity of the adsorbent, and K L represents the affinity constant. Moreover, K F ((g mg -1 ) (L mg -1 ) 1/n ) and n are the adsorption constant and meanwhile 1/n is a measure of the exchange intensity or surface heterogeneity. Equations for describing selectivity performances. The distribution coefficient (K d ), selectivity coefficient (k), and relative selectivity coefficient (k') of LTL, QRT, HDQ and 4C3H are calculated according to Eqs S-6

7 = (7) where Q e (mg g -1 ) is the equilibrium adsorption capacity, and K d (L g -1 ) represents the distribution coefcient and C e (mg L -1 ) is the equilibrium concentration. = ( ) ( ) (8) where x represents the structural analog. k' in Eq. 9 indicates the enhanced extent of adsorption affinity and selectivity of DM-MIPs for the template. k M and k N are the selectivity coefficients of DM-MIPs and DM-NIPs, respectively. = (9) S-7

8 Figure S1 The standard curve of Zn 2+. Figure S2 Raman spectra of HNTs, HNTs-PDA, HNTs-PDA-Br, HNTs-PDA-PVLD and DM-MIPs ranged from 3000 cm -1 to 200 cm -1. S-8

9 Figure S3 Results of contact angle of HNTs-PDA (A) and HNTs-PDA-Br (B). Figure S4 The EDS spectra and a standard atom counting result of DM-MIPs. Figure S5 Optical micrographs of DM-MIPs suspension (1.0 mg/5.0 ml) at three time intervals (0 min (A), 5.0 min (B), and 8.0 min (C)). Figure S6 Laser scanning confocal microscope (LSCM) images of DM-MIPs mixed with ARS at S-9

10 ph= 8.5 (A), ph= 7.0 (B), and ph=4.0 (C). Figure S7 Adsorption capacities of DM-MIPs for LTL in continuous adsorption-regeneration runs (A) and adsorption kinetic curve of DM-MIPs after six regeneration cycles (B). S-10