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Folate-modified silicon carbide nanoparticles as multiphoton imaging nanoprobes for cancer-cell-specific labeling

Boksebeld, M., Kilin, V., Géloën, A., Ceccone, G., Jaffal, A., Schmidt, C., Alekseev, S., Lysenko, V., Wolf, J. P., Bonacina, L., Souteyrand, E., Chevolot, Y., Monnier, V.
RSC advances 2017 v.7 no.44 pp. 27361-27369
X-ray photoelectron spectroscopy, colorimetry, folic acid, image analysis, mass spectrometry, microscopy, nanoparticles, neoplasm cells, polyethylene glycol, silane, silicon carbide, titration, zeta potential
Interest in multiphoton microscopy for cell imaging has considerably increased over the last decade. Silicon carbide (SiC) nanoparticles exhibit strong second-harmonic generation (SHG) signal, and can thus be used as nonlinear optical probes for cell imaging. In this study, the surface of SiC nanoparticles was chemically modified to enable cancer-cell-specific labeling. In a first step, an aminosilane was grafted onto the surface of SiC nanoparticles. The resulting nanoparticles were further modified with folic acid, using an isothiocyanate-based coupling method. Nanoparticles from different functionalization steps were investigated by zeta potential measurement, colorimetric titration, infrared and ultraviolet-visible (UV-Vis) absorption spectroscopy, X-ray photoelectron spectroscopy (XPS), and time-of-flight secondary ion mass spectrometry (ToF-SIMS). Characterization results confirmed successful covalent grafting of silane and folic acid to nanoparticle surface. Finally, the efficacy of these folate-modified SiC nanoparticles for cancer-cell-specific labeling was evaluated by multiphoton microscopy, by measuring SHG-emitting cell area on multiphoton images. The average cancer-cell labeling percentage was about 48%, significantly higher than for negative controls (healthy cells, competition assay and poly(ethylene glycol) modified-SiC nanoparticles), where it ranged between 10% and 15%. These results demonstrated good efficiency and specificity for these folate-modified SiC nanoparticles in cancer-cell-specific labeling.