Preparation of Fe3O4@SiO2@Layered Double Hydroxide CoreâShell ...
Supplementary Information for
Preparation of Fe3O4@SiO2@Layered Double Hydroxide Core–Shell Microspheres for Magnetic Separation of Proteins Mingfei Shao, Fanyu Ning, Jingwen Zhao, Min Wei,* David G. Evans, and Xue Duan State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, P. R. China
*
Corresponding author. Tel: +86-10-64412131; Fax: +86-10-64425385.
E-mail address: [email protected]
Preparation of Fe3O4@SiO2@M(II)Al-LDH (M= Co, Zn, Mg) microspheres Preparation of Fe3O4@SiO2@CoAl-LDH microspheres: An in situ crystallization of a CoAl-LDH nanoplatelet shell on the surface of Fe3O4@SiO2@AlOOH microspheres was carried out. In a typical procedure, 0.01 mol of CoCl2·6H2O and 0.015 mol of NH4NO3 were dissolved in deionized water to form a solution with a total volume of 70 mL. The Fe3O4@SiO2@AlOOH microspheres (0.1 g) were placed in the above solution in an autoclave at 100 °C for 48 h. Finally, the resulting Fe3O4@SiO2@CoAl-LDH microspheres were separated by a magnet, rinsed with ethanol and dried at room temperature. Preparation of Fe3O4@SiO2@ZnAl-LDH microspheres: The ZnAl-LDH microspheres were prepared by an in situ growth technique according to our previous report.1 Zn(NO3)2·6H2O (0.01 mol) and NH4NO3 (0.06 mol) were dissolved in deionized water (70 mL), and 1% ammonia solution was then slowly added until the pH reached 6.5. The
S1
Fe3O4@SiO2@AlOOH microspheres (0.1 g) were immersed into the above solution in a glass vessel at 75 °C for 36 h. Finally, the resulting Fe3O4@SiO2@ZnAl-LDH microspheres were separated by a magnet, rinsed with ethanol and dried at room temperature. Preparation of Fe3O4@SiO2@MgAl-LDH microspheres: The MgAl-LDH shell was obtained on the surface of Fe3O4@SiO2@AlOOH microspheres by means of urea hydrolysis method similar to the previous report by our group.2 A solution of Mg(NO3)2 ·6H2O (0.005 mol) and urea (0.04 mol) in 100 ml of deionized water was placed in a glass vessel. The as-prepared Fe3O4@SiO2@AlOOH microspheres (0.1 g) were immersed into the solution. The glass vessel was sealed and maintained at 80 °C for 1 day. After cooling, the resulting Fe3O4@SiO2@MgAl-LDH microspheres were separated by a magnet, rinsed with ethanol and dried at room temperature. Preparation of comparison samples Preparation of NiAl-LDH shell on the surface of Fe3O4@SiO2 without AlOOH coating. For comparison, the Fe3O4@SiO2@LDH microspheres were synthesized in the absence of AlOOH layer similar to the previous report.3 In a typical procedure, 0.1 g of Fe3O4@SiO2 microspheres were dispersed into a 70 ml of deionized water containing Ni(NO3)2·6H2O (0.01 mol), Al(NO3)3·9H2O (0.005 mol) and urea (0.015 mol), sealed in an autoclave and heated at 120 °C for 48 h. The resulting product was filtered, washed thoroughly with deionized water and anhydrous ethanol and subsequently dried at room temperature. Preparation of NiAl-LDH shell on the surface of Fe3O4@AlOOH without SiO2 coating. The Fe3O4 microspheres were dispersed in the AlOOH primer sol for 1 h with vigorous agitation, followed by withdrawing the microspheres by a magnet and washing thoroughly with ethanol.
S2
The resulting Fe3O4@AlOOH microspheres were dried in air for 30 min. The whole process (dispersion, withdrawing, drying) was repeated 10 times. The Fe3O4@AlOOH microspheres (0.1 g) were placed in a solution (70 mL) containing Ni(NO3)2·6H2O (0.01 mol) and NH4NO3 (0.015 mol) in an autoclave at 100 °C for 48 h. The resulting Fe3O4@NiAl-LDH microspheres were separated by a magnet, rinsed with ethanol and dried at room temperature.
Figure S1. SEM image of the Fe3O4@SiO2@NiAl-LDH microspheres.
Figure S2. (A) The EDX spectrum of the Fe3O4@SiO2@NiAl-LDH microspheres; (B) the corresponding elemental contents.
S3
Figure S3. SEM images of (A) Fe3O4@SiO2@CoAl-LDH, (B) Fe3O4@SiO2@ZnAl-LDH, and (C) Fe3O4@SiO2@MgAl-LDH microspheres.
Table S1. M(II)/Al ratio of the Fe3O4@SiO2@M(II)Al-LDH (M=Ni, Co, Zn, Mg) microspheres M(II)/Al Microspheres ratio Fe3O4@SiO2@NiAl-LDH 4.18 Fe3O4@SiO2@CoAl-LDH 4.05 Fe3O4@SiO2@ZnAl-LDH 4.29 Fe3O4@SiO2@MgAl-LDH 4.49
S4
Figure S4. (A) The NiAl-LDH material synthesized on the surface of Fe3O4@SiO2 particles without an AlOOH coating. (B) The Fe3O4@NiAl-LDH microspheres synthesized without a SiO2 layer.
Figure S5. FT-IR spectra of (a) Fe3O4 particles, (b) Fe3O4@SiO2, (c) Fe3O4@SiO2@AlOOH and (d) Fe3O4@SiO2@NiAl-LDH microspheres. The FT-IR spectrum of Fe3O4@SiO2@NiAl-LDH microspheres (Figure S5, curve d) shows a new band at 2205 cm–1 due to the presence of cyanate (CNO−) anions in the interlayer region of NiAl-LDH.4
S5
Figure S6. The N2-sorption isotherms and pore-size distribution (inset) of the Fe3O4@SiO2@M(II)Al-LDH (M = Co, Zn, Mg) microspheres.
Figure S7. Room temperature (300 K) magnetic hysteresis loops of Fe3O4, Fe3O4@SiO2, Fe3O4@SiO2@AlOOH and Fe3O4@SiO2@NiAl-LDH microspheres.
S6
Scheme S1. A schematic representation of the magnetically recyclable protein separation process using Fe3O4@SiO2@NiAl-LDH microspheres.
Figure S8. XPS spectra in the (A) Al 2p and (B) Fe 2p regions for the Fe3O4@SiO2@NiAl-LDH microspheres before (curve a) and after (curve b) reaction with His-tagged GFP.
S7
Figure S9. Florescence intensity of the His-tagged GFP solution as a function of adsorption time using different types of LDH microspheres.
Figure S10. Photographs of His-tagged GFP solutions after reaction for 30 min with different LDH microspheres.
S8
Figure S11. Plots of binding capacities for His-tagged GFP of various LDH microspheres as a function of reaction time.
Figure S12. The zeta potential distribution spectra for the Fe3O4@SiO2@M(II)Al-LDH (M = Ni, Co, Zn, Mg) microspheres. In order to further study the effect of the charge density of different LDH microspheres, zeta potential analysis was carried out using photon correlation spectroscopy (PCS, Nano Granularity Analyzer Zetasizer-3000HS, Malvern Instruments). The zeta potential values were determined to be 26.0, 36.9, 24.2 and 17.0 mV for Fe3O4@SiO2@NiAl-LDH, Fe3O4@SiO2@CoAl-LDH,
Fe3O4@SiO2@ZnAl-LDH S9
and
Fe3O4@SiO2@MgAl-LDH,
respectively (Figure S12). The results show the surface potential decreases in the order: Co/Al > Ni/Al > Zn/Al > Mg/Al, which is consistent with the elemental analysis results (Table S1). However, no correlation between adsorption capacity and surface potential can be found.
Figure S13. (A) TEM and (B) SEM images of the Fe3O4@SiO2@NiAl-LDH after five reaction cycles with His-tagged GFP solution.
References: 1. Zhang, F. Z.; Zhao, L. L.; Chen, H. Y.; Xu, S. L.; Evans, D. G.; Duan, X. Angew. Chem. Int. Ed. 2008, 47, 2466–2469. 2. Lv, Z.; Zhang, F. Z.; Lei, X. X.; Yang, L.; Xu, S. L.; Duan, X. Chem. Eng. Sci. 2008, 63, 4055–4062. 3. Pan, D. K.; Zhang, H.; Fan, T.; Chen, J. G.; Duan X. Chem. Commun. 2011, 47, 908–910. 4. Shu, X.; Zhang, W. H.; He, J.; Gao, F. X.; Zhu Y. X. Solid State Sci. 2006, 8, 634–639.
S10
Preparation of Fe3O4@SiO2@Layered Double Hydroxide Core–Shell Microspheres for Magnetic Separation of Proteins Mingfei Shao, Fanyu Ning, Jingwen Zhao, Min Wei,* David G. Evans, and Xue Duan State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, P. R. China
*
Corresponding author. Tel: +86-10-64412131; Fax: +86-10-64425385.
E-mail address: [email protected]
Preparation of Fe3O4@SiO2@M(II)Al-LDH (M= Co, Zn, Mg) microspheres Preparation of Fe3O4@SiO2@CoAl-LDH microspheres: An in situ crystallization of a CoAl-LDH nanoplatelet shell on the surface of Fe3O4@SiO2@AlOOH microspheres was carried out. In a typical procedure, 0.01 mol of CoCl2·6H2O and 0.015 mol of NH4NO3 were dissolved in deionized water to form a solution with a total volume of 70 mL. The Fe3O4@SiO2@AlOOH microspheres (0.1 g) were placed in the above solution in an autoclave at 100 °C for 48 h. Finally, the resulting Fe3O4@SiO2@CoAl-LDH microspheres were separated by a magnet, rinsed with ethanol and dried at room temperature. Preparation of Fe3O4@SiO2@ZnAl-LDH microspheres: The ZnAl-LDH microspheres were prepared by an in situ growth technique according to our previous report.1 Zn(NO3)2·6H2O (0.01 mol) and NH4NO3 (0.06 mol) were dissolved in deionized water (70 mL), and 1% ammonia solution was then slowly added until the pH reached 6.5. The
S1
Fe3O4@SiO2@AlOOH microspheres (0.1 g) were immersed into the above solution in a glass vessel at 75 °C for 36 h. Finally, the resulting Fe3O4@SiO2@ZnAl-LDH microspheres were separated by a magnet, rinsed with ethanol and dried at room temperature. Preparation of Fe3O4@SiO2@MgAl-LDH microspheres: The MgAl-LDH shell was obtained on the surface of Fe3O4@SiO2@AlOOH microspheres by means of urea hydrolysis method similar to the previous report by our group.2 A solution of Mg(NO3)2 ·6H2O (0.005 mol) and urea (0.04 mol) in 100 ml of deionized water was placed in a glass vessel. The as-prepared Fe3O4@SiO2@AlOOH microspheres (0.1 g) were immersed into the solution. The glass vessel was sealed and maintained at 80 °C for 1 day. After cooling, the resulting Fe3O4@SiO2@MgAl-LDH microspheres were separated by a magnet, rinsed with ethanol and dried at room temperature. Preparation of comparison samples Preparation of NiAl-LDH shell on the surface of Fe3O4@SiO2 without AlOOH coating. For comparison, the Fe3O4@SiO2@LDH microspheres were synthesized in the absence of AlOOH layer similar to the previous report.3 In a typical procedure, 0.1 g of Fe3O4@SiO2 microspheres were dispersed into a 70 ml of deionized water containing Ni(NO3)2·6H2O (0.01 mol), Al(NO3)3·9H2O (0.005 mol) and urea (0.015 mol), sealed in an autoclave and heated at 120 °C for 48 h. The resulting product was filtered, washed thoroughly with deionized water and anhydrous ethanol and subsequently dried at room temperature. Preparation of NiAl-LDH shell on the surface of Fe3O4@AlOOH without SiO2 coating. The Fe3O4 microspheres were dispersed in the AlOOH primer sol for 1 h with vigorous agitation, followed by withdrawing the microspheres by a magnet and washing thoroughly with ethanol.
S2
The resulting Fe3O4@AlOOH microspheres were dried in air for 30 min. The whole process (dispersion, withdrawing, drying) was repeated 10 times. The Fe3O4@AlOOH microspheres (0.1 g) were placed in a solution (70 mL) containing Ni(NO3)2·6H2O (0.01 mol) and NH4NO3 (0.015 mol) in an autoclave at 100 °C for 48 h. The resulting Fe3O4@NiAl-LDH microspheres were separated by a magnet, rinsed with ethanol and dried at room temperature.
Figure S1. SEM image of the Fe3O4@SiO2@NiAl-LDH microspheres.
Figure S2. (A) The EDX spectrum of the Fe3O4@SiO2@NiAl-LDH microspheres; (B) the corresponding elemental contents.
S3
Figure S3. SEM images of (A) Fe3O4@SiO2@CoAl-LDH, (B) Fe3O4@SiO2@ZnAl-LDH, and (C) Fe3O4@SiO2@MgAl-LDH microspheres.
Table S1. M(II)/Al ratio of the Fe3O4@SiO2@M(II)Al-LDH (M=Ni, Co, Zn, Mg) microspheres M(II)/Al Microspheres ratio Fe3O4@SiO2@NiAl-LDH 4.18 Fe3O4@SiO2@CoAl-LDH 4.05 Fe3O4@SiO2@ZnAl-LDH 4.29 Fe3O4@SiO2@MgAl-LDH 4.49
S4
Figure S4. (A) The NiAl-LDH material synthesized on the surface of Fe3O4@SiO2 particles without an AlOOH coating. (B) The Fe3O4@NiAl-LDH microspheres synthesized without a SiO2 layer.
Figure S5. FT-IR spectra of (a) Fe3O4 particles, (b) Fe3O4@SiO2, (c) Fe3O4@SiO2@AlOOH and (d) Fe3O4@SiO2@NiAl-LDH microspheres. The FT-IR spectrum of Fe3O4@SiO2@NiAl-LDH microspheres (Figure S5, curve d) shows a new band at 2205 cm–1 due to the presence of cyanate (CNO−) anions in the interlayer region of NiAl-LDH.4
S5
Figure S6. The N2-sorption isotherms and pore-size distribution (inset) of the Fe3O4@SiO2@M(II)Al-LDH (M = Co, Zn, Mg) microspheres.
Figure S7. Room temperature (300 K) magnetic hysteresis loops of Fe3O4, Fe3O4@SiO2, Fe3O4@SiO2@AlOOH and Fe3O4@SiO2@NiAl-LDH microspheres.
S6
Scheme S1. A schematic representation of the magnetically recyclable protein separation process using Fe3O4@SiO2@NiAl-LDH microspheres.
Figure S8. XPS spectra in the (A) Al 2p and (B) Fe 2p regions for the Fe3O4@SiO2@NiAl-LDH microspheres before (curve a) and after (curve b) reaction with His-tagged GFP.
S7
Figure S9. Florescence intensity of the His-tagged GFP solution as a function of adsorption time using different types of LDH microspheres.
Figure S10. Photographs of His-tagged GFP solutions after reaction for 30 min with different LDH microspheres.
S8
Figure S11. Plots of binding capacities for His-tagged GFP of various LDH microspheres as a function of reaction time.
Figure S12. The zeta potential distribution spectra for the Fe3O4@SiO2@M(II)Al-LDH (M = Ni, Co, Zn, Mg) microspheres. In order to further study the effect of the charge density of different LDH microspheres, zeta potential analysis was carried out using photon correlation spectroscopy (PCS, Nano Granularity Analyzer Zetasizer-3000HS, Malvern Instruments). The zeta potential values were determined to be 26.0, 36.9, 24.2 and 17.0 mV for Fe3O4@SiO2@NiAl-LDH, Fe3O4@SiO2@CoAl-LDH,
Fe3O4@SiO2@ZnAl-LDH S9
and
Fe3O4@SiO2@MgAl-LDH,
respectively (Figure S12). The results show the surface potential decreases in the order: Co/Al > Ni/Al > Zn/Al > Mg/Al, which is consistent with the elemental analysis results (Table S1). However, no correlation between adsorption capacity and surface potential can be found.
Figure S13. (A) TEM and (B) SEM images of the Fe3O4@SiO2@NiAl-LDH after five reaction cycles with His-tagged GFP solution.
References: 1. Zhang, F. Z.; Zhao, L. L.; Chen, H. Y.; Xu, S. L.; Evans, D. G.; Duan, X. Angew. Chem. Int. Ed. 2008, 47, 2466–2469. 2. Lv, Z.; Zhang, F. Z.; Lei, X. X.; Yang, L.; Xu, S. L.; Duan, X. Chem. Eng. Sci. 2008, 63, 4055–4062. 3. Pan, D. K.; Zhang, H.; Fan, T.; Chen, J. G.; Duan X. Chem. Commun. 2011, 47, 908–910. 4. Shu, X.; Zhang, W. H.; He, J.; Gao, F. X.; Zhu Y. X. Solid State Sci. 2006, 8, 634–639.
S10
