SUPPORTING INFORMATION

Transcription

1 Electronic Supplementary Material (ESI) for Nanoscale. This journal is The Royal Society of Chemistry 2014 SUPPORTING INFORMATION Sugar and ph Dual-Responsive Mesoporous Silica Nanocontainers Based on Competitive Binding Mechanisms M. Deniz Yilmaz, a,b Min Xue, a,c Michael W. Ambrogio, d Onur Buyukcakir, b Yilei Wu, b Marco Frasconi, b Xinqi Chen, d Majed S. Nassar, e J. Fraser Stoddart b,* and Jeffrey I. Zink c,* a These authors contributed equally to this work. b Center for the Chemistry of Integrated Systems, Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL U.S.A. c Department of Chemistry and Biochemistry, University of California, Los Angeles, 607 Charles E. Young Drive East, Los Angeles, CA U.S.A. d Northwestern University Atomic and Nanoscale Characterization Experimental (NUANCE) Center, 2220 Campus Drive, Evanston, IL U.S.A. e National Center for Nano Technology Research, King Abdulaziz City of Science and Technology (KACST) P.O. Box 6086, Riyadh 11442, Kingdom of Saudi Arabia. *Corresponding authors stoddart@northwestern.edu (J.F. Stoddart) zink@chem.ucla.edu (J.I. Zink) Table of Contents 1. Synthetic Schemes S2 2. Electron Microscopy S3 3. Nitrogen Adsorption/Desorption Isotherms S4 4. FT-IR Spectroscopy S5 5. Isothermal Titration Calorimetry S6 6. X-Ray Photoelectron Spectroscopy S7 7. Time-of-Flight Secondary Ion Mass Spectrometry S9 8. Dynamic Light Scattering Studies of the Nanoparticles S12

2 1. Synthetic Schemes 2. Electron Microscopy TEM Images of PBA-MSNs and propidium iodide dye (PI) loaded CD-PBA-MSNs show (Figure S1) the formation of uniform mesoporous nanoparticles in the form of spherical shapes with an average nanoparticle diameter of 100 nm. S2

3 Figure S1. TEM Images of (a) PBA-MSNs, and (b) PI-loaded CD-PBA MSNs; (c) A higher resolution TEM image of PBA-MSNs; (d) SEM image of PBA-MSNs. S3

4 3. Nitrogen Adsorption/Desorption Isotherms Specific surface areas of PBA-MSNs and C-βCD capped PBA-MSNs were calculated from the N 2 adsorption/desorption isotherms (Figure S2) and found to be 727 m 2 /g for PBA-MSNs and 601 m 2 /g for C-βCD capped PBA-MSNs. Figure S2. N 2 adsorption/desorption isotherms for (a) PBA-MSNs and (b) C-βCD capped PBA- MSNs. S4

5 4. FT-IR Spectroscopy Figure S3. FTIR spectra of (a) as-synthesized MCM-41; (b) MCM-41 after removal of surfactant; (c) AP-MSN and (d) PBA-MSN. The surface modification of the nanoparticles was characterized by FTIR spectroscopy. The strong band around 2900 cm -1 was assigned (Figure S3a) to the stretching of the C H bonds of the cetyltrimethyl ammonium bromide into the pores of MCM-41. After removal of the surfactant, the C-H stretching disappeared (Figure S3b). In AP-MSN (Figure S3c), the C H stretching band appears again with low intensity after aminopropyl monolayer formation. Finally, in PBA-MSN, a new band around 1630 cm -1 confirms (Figure S3d) amide formation. S5

6 5. Isothermal Titration Calorimetry Isothermal titration calorimetry (ITC) experiments were performed to determine the binding constant of C-βCD and βcd to 4-carboxy-3- fluorophenylboronic acid in H 2 O. An ITC titration of 10 mm 4-carboxy-3- fluorophenylboronic acid with 1 mm C-βCD showed (Figure S3a) a typical 1:1 binding event. Fitting to a 1:1 binding model yielded a K a value of 6 x 10 3 M -1. In a control experiment, an ITC titration of 10 mm 4-carboxy-3-fluorophenylboronic acid with 1 mm β-cd led (Figure S3b) to a weaker binding strength with a K a value of 1 x 10 2 M -1. Figure S4. Heat evolved per injection (markers) and fits to a 1:1 model (lines) for the isothermal calorimetric titrations of 10 mm 4-carboxy-3- fluorophenylboronic acid with (a) 1 mm C-βCD and (b) 10 mm 4-carboxy-3-fluorophenylboronic acid to 1 mm β-cd. S6

7 6. X-Ray Photoelectron Spectroscopy X-Ray photoelectron spectroscopy (XPS) was used to monitor the monolayer formation on MSNs. Figure S5 shows the XPS survey scans of AP-MSN, PBA-MSN, and CD-PBA-MSN. The high-resolution XPS spectra of the C 1s region for AP-MSN, PBA-MSN, and CD-PBA- MSN are depicted in Figure S6a, b, and c, respectively. For the CD-PBA-MSP sample, the large peak at ev is indicative of the presence of β-cd on the surfaces of the nanoparticles. Figure S5. Comparison of wide-scan XPS spectra for AP-MSNs (red curve), PBA-MSNs (green curve) and CD-PBA-MSNs (blue curve). S7

8 Figure S6. High-resolution XPS spectra of the C1s region for (a) AP-MSNs, (b) PBA-MSNs, and (c) CD-PBA-MSNs. S8

9 7. Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS) Figure S7. TOF-SIMS spectra (positive ion mode) confirming the presence of boron in the PBA-MSN sample (above) which was not present in the AP-MSN sample (below). S9

10 Figure S8. TOF-SIMS spectra (negative ion mode) confirming the presence of fluorine in the PBA-MSN sample (above) which was not present in the AP-MSN sample (below). S10

11 Figure S9. TOF-SIMS spectra of CD-PBA-MSN. The top spectrum (positive-ion mode) confirms the presence of boron, and the bottom spectrum (negative-ion mode) shows the presence of fluorine. S11

12 8. Dynamic Light Scattering Studies of the Nanoparticles The stability of PBA-MSNs was studied through monitoring the size of the nanoparticles over time. Nanoparticles were suspended in either PBS or 1.5% BSA/PBS and the result is shown in Table S1. The nanoparticles are fairly stable in these solutions and no obvious degradation was observed. Table S1 Dynamic Light Scattering Results of the Nanoparticles As-Synthesized PBA-MSNs 1 week 1 month in PBS 140 ± 15 nm 140 ± 12 nm 130 ± 14 nm in 1.5 % BSA/PBS 120 ± 10 nm 130 ± 9 nm 120 ± 12 nm S12