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. Author manuscript; available in PMC: 2020 May 1.
Published in final edited form as: Environ Sci Nano. 2019 Apr 10;6(5):1516–1526. doi: 10.1039/C8EN01381K

Figure 5.

Figure 5.

(a) Fluorescence emission spectra of FITC-CNF excited at 470 nm prepared at various pH values (pH 2.6 – 9). (b) Emission spectra of FITC-CNC excited at 480 nm prepared at various pH values (pH 2.6 – 9). For both (a) and (b), “Controls” are overlaid emission spectra of their untagged counterparts dispersed in the same buffers. Summary of fluorescence intensities at 520 nm obtained from FITC-tagged CNF (c) and FITC-tagged CNC (d) exposed to different pH values and compared against their respective supernatants following centrifugation. Dispersions of both FITC-tagged materials were further washed with PBS to evaluate the sustainability of fluorescence intensity at various pH values. The survey reflects the pH sensitivity of FITC fluorescence. At the same time, FITC is strongly attached to CNM and its fluorescence recovers in PBS. All suspensions are prepared at 0.5 mg/ml; standard deviations are obtained from 3 replicates (n=3).