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Supporting Information
SYNTHESIS AND CHARCATERIZATION OF
NANOSTRUCTURED POROUS SILICON/CARBON DOTS–
HYBRID FOR ORTHOGONAL MOLECULAR DETECTION
Naama Massad-Ivanir1§, Susanta Kumar Bhunia2§, Nitzan Raz1, Ester Segal1,3* and Raz
Jelinek2,4*
1Department of Biotechnology and Food Engineering, Technion – Israel Institute of Technology, Haifa 3200003, Israel2Department of Chemistry, Ben Gurion University of the Negev, Beer Sheva 8410501,Israel3The Russell Berrie Nanotechnology Institute, Technion – Israel Institute of Technology, Haifa 3200003, Israel4Ilse Katz Institute for Nanotechnology, Ben Gurion University of the Negev,Beer Sheva 8410501, Israel§Equal contribution
*Prof. Ester Segal Corresponding-AuthorE-mail: [email protected]*Prof. Raz Jelinek Corresponding-AuthorE-mail: [email protected]
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Figure S1. Optical response, expressed as the relative EOT, of the PSiO2/C-dot hybrid vs. time during incubation in a PBS solution for 10 h. The hybrid was incubated in a PBS solution for 10 h and the reflectivity spectra were continuously collected. A stable EOT baseline was observed throughout the entire experiment.
EOT values remain constant throughout
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the experiment, indicating the stability of allEOT values remain constant throughout
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the experiment, indicating the stability of allEOT values remain constant throughout
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the experiment, indicating the stability of al
2.0 2.5 3.0 3.5 4.0 4.5 5.00
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ber (
%)
Diameter (nm)
Figure S2. Size distribution of extracted C-dots, inferred from the HRTEM experiment. Average size of 3.7 ± 0.6 nm.
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Figure S3. Transmission electron microscopy (TEM) image of "free" C-dots (synthesized in solution). The average particles’ size is of approximately 10 nm.
Figure S4: UV–Vis absorption spectra of (a) confined C-dots (after the extraction from the PSiO2 matrix); (b) "free" C-dots (synthesized in solution). Quantum yield of the C-dots was 0.7% and 1.2% for confined C-dots (after the extraction from the PSiO2 matrix) and "free", respectively. It is important to note that the quantum yield is measured after the confined C-dots were extracted from the PSiO2 matrix, a process that may reduce the quantum yield value.
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Figure S5. Relative EOT changes upon infiltration of trypsin into the hybrid at different concentrations, ranging between 0-43 µM (n≥3 for each concentration), *Significantly different (t-test, p<0.05). The reflectivity response is found to be proportional to trypsin concentration and a linear correlation is demonstrated (R2=0.95).
Figure S6. Relative EOT changes upon infiltration of trypsin into neat PSiO2 at different concentrations, ranging between 0-43 µM (n=3 for each concentration), *Significantly different (t-test, p<0.05). The reflectivity response is found to be proportional to trypsin concentration and a poor linear correlation is demonstrated (R2=0.75).
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Table S1. Sensing performances of the hybrid system upon trypsin in comparison to control systems (neat PSiO2 and “free” C-dots).
* Experimental detection limit cannot be determined.** No linear response range was found
Figure S7. Fluorescence intensity changes upon infiltration of trypsin into the hybrid at different concentrations, ranging between 0-43 µM (n=3 for each concentration). The fluorescence intensity response is found to be proportional to trypsin concentration and a linear correlation is demonstrated (R2=0.95).
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Figure S8. Fluorescence emission spectra of neat PSiO2 at different excitation wavelengths.
Figure S9. Fluorescence intensity changes of C-dots in solution (exc. 475 nm), after incubation with trypsin at different concentrations, ranging between 0-43 µM (n=3 for each concentration). Lower sensitivity is achieved in comparison to the hybrid system; no change in the EOT signal is observed for trypsin concentration lower than 21.5 µM.
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Figure S10. Optical response to ATP expressed in terms of relative EOT, of neat PSiO2 vs. exposure time to ATP infiltration into the nanostructure. (i) PBS buffer; (ii) introduction of 5 mM ATP; the neat PSiO2 is fixed in a custom-made flow-cell, and the reflectivity spectra were recorded every 15 sec.
Figure S11. Fluorescence intensity of (a) C-dot/PSiO2 hybrids and (b) "free" C-dots (exc. 475 nm) after incubation with ATP at different concentrations. In the hybrid system, the quenching of the C-dots’ fluorescence is found to be proportional to ATP concentration and a linear correlation is demonstrated (R2=0.98), while for the "free" C-dots a constant quenching effect is observed for high ATP concentrations (≥1 mM).
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Table S2. Sensing performances of the hybrid system upon ATP in comparison to control systems (neat PSiO2 and “free” C-dots).
* Calculated detection limit cannot be determined.** No linear response range was found
Figure S12. Image of the bimodal experimental setup. A customized Zeiss upright microscope equipped with an Ocean Optics charge-coupled device (CCD) USB 4000 spectrometer was used to collect both the interferometric reflectance spectra and the fluorescent signal. A two-port adapter was utilized to selectively transmit the light either to the collimator, which was coupled to a fiber-optic, or to the microscope camera (Axio Cam MRc, Zeiss). The PSiO2/C-dot hybrid was fixed to the microscope stage under the microscope objective. The light from a halogen source (halogen100 illuminator, Zeiss) was focused through an A-Plan objective (10X, 0.25 NA, Zeiss); the size of the illumination spot was controlled by the microscope’s iris.
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