Supporting Information
Synthesis and Characterization of Biocompatible and Size-Tunable Multifunctional Porous Silica Nanoparticles Yu-Shen Lin and Christy L. Haynes* Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455 (USA) *
Addressed correspondence to
[email protected] Experimental Section 1. Synthesis of Stöber SiO2 nanoparticles and PEG coated Stöber SiO2 nanoparticles The Stöber SiO2 nanoparticles were synthesized by a modified version developed by Stöber et al.1 Typically, 0.75 mL of aqueous ammonia (28~30 wt %) was added to 40 mL of 95% ethanol at 40 oC. Then 0.5 mL of tetraethoxy orthosilicate (TEOS) was introduced to the mixture. The hydrolysis and condensation reactions proceeded under continuous stirring at 40 oC for 12 hours. The ultrafine SiO2 colloids were collected by centrifuge, washed with DPBS three times, and then redispersed in DPBS for hemolysis experiments. The SiO2@PEG nanoparticles were obtained by adding 50 μL of PEG-silane to the as-prepared SiO2 nanoparticle solution. The PEG coating was carried out at two different time intervals (12 and 24 hours). All purification and followed the procedure described above. 2. Synthesis of Fe3O4@SiO2 nanoparticles The Fe3O4 coated SiO2 nanoparticles were synthesized by a similar procedure developed by Lu et al.2 Two mg of oleic acid capped Fe3O4 nanoparticles was suspended in 10 mL of cyclohexane at room temperature. Then 1.8 g of Triton X-100, 1.6 mL of hexanol, and 0.34 mL of H2O were added with 1
stirring to form water-in-oil microemulsion. After 15 minutes, 40 µL of (TEOS) was added to the mixture. One-half hour later, 0.1 mL of aqueous ammonia (28~30 wt %) was added to initiate the TEOS hydrolysis and condensation. After 24 hours, ethanol was added to destabilize the microemulsion system and precipitate the Fe3O4@SiO2 nanoparticles. The Fe3O4@SiO2 nanoparticles were isolated via centrifugation and washed with ethanol five times and deionized water five times to remove adherent surfactant and unreacted chemicals.
Figure S1. (Left) As-synthesized oleic acid capped Fe3O4 NPs dispersed in chloroform and (Right) CTAB/PVP stabilized Fe3O4 NPs in water.
2
Figure S2. (a) TEM image and (b) Particle size distribution of as-synthesized oleic acid capped Fe3O4 NPs (n=150).
Figure S3. TEM images of Fe3O4@FITC-MSNs@PEG (a) without the addition of PVP and (b) with the addition of PVP during the synthesis.
Figure S4. Particle size distributions of surfactant-free Fe3O4@FITC-MSNs@PEG with varied diameters. (a) 33±5.4 nm Fe3O4@FITC-MSNs@PEG, n=180. (b) 42±5.6 nm Fe3O4@FITCMSNs@PEG, n=125. (c) 53±7.1 nm Fe3O4@FITC-MSNs@PEG, n=100. (d) 67±7.1 nm Fe3O4@FITCMSNs@PEG, n=130. 3
Figure S5. The room temperature hydrodynamic size distribution of surfactant-free 33 nm Fe3O4@FITC-MSNs@PEG NPs in (a) deionized water and (b) PBS solution based on dynamic light scattering. (c) Stability test of the 0.2 mg/mL of surfactant-free 33 nm Fe3O4@FITC-MSNs@PEG NPs in deionized water and PBS. (d) The photographs of surfactant-free 33 nm Fe3O4@FITC-MSNs@PEG NPs in deionized water and PBS showed excellent colloidal stability without any visible aggregation.
Figure S6. TEM images of (a) Stöber SiO2 NPs and (b) Fe3O4@SiO2 NPs. 4
Figure S7. The photograph of RBCs incubated with Fe3O4@FITC-MSNs at different concentrations ranging from 12.5 to 1000 μg/mL for 3 hours.
Figure S8. Hemolysis of RBCs in the presence of 33 nm Fe3O4@FITC-MSNs@PEG monitored at different incubation times (3, 6, 12, 18, 24, and 36 hours). The concentration of 33 nm Fe3O4@FITCMSNs@PEG is 1000 μg/mL. Data are represented to mean + SD, n=3. References (1) Stöber, W.; Fink, A.; Bohn E. J. Colloid Interface Sci. 1968, 26, 62. (2) Lu, C.-W.; Lu, C.-W.; Hung, Y.; Hsiao, J.-K.; Yao, M.; Chung, T.-H.; Lin, Y.-S.; Wu, S.-H.; Hsu, S.-C.; Liu, H.-M.; Mou, C.-Y.; Yang, C.-S.; Huang, D.-M.; Chen, Y.-C. Nano Lett. 2007, 7, 149. 5
