Synthesis of Fluorophore Decorated Single-Walled Carbon Nanotubes for Cytocompatibility.

We report rhodamine based fluorophore derivative for the stable dispersion of single-walled carbon nanotubes (SWCNTs), which can afford better fluorescent label to carbon nanotubes (CNTs). The nanotubes-fluorophore conjugates are helpful in achieving stable dispersion in polar and non-polar solvents with intense fluorescence. The product was characterized through NMR, Mass spectrometry, Raman, XPS, SEM, AFM and Fluorescence measurements. The formation of SWCNT-g- Rhodamine was confirmed by the presence of D and G bands in Raman spectrum. The alkyl and aryl groups in the range of 14.8, 17.6, 38.1 and 96.3 ppm confirms the grafting of the nanocomposite through NMR. The morphological studies were carried out intensively for analyzing SWCNTs stable dispersion and the results from EDAX measurements shows the elements weight% of C: 35.09 and N: 30.1 concludes that SWCNTs are completely grafted onto rhodamine derivatives. The application of SWCNTs fluorophore conjugates were analyzed by cell viability studies using MTT assay and exhibits less toxic compare to other functionalized CNTs. The viability of percentage increases with decrease in the concentration of SWCNT-COCl with 91.7% of live cells even after 24 h at a concentration of 250 μg for SWCNT-g-Rhodamine. The fluorescent images obtained during viability analysis shows enhanced fluorescence for living cells in case of SWCNT-g-Rhodamine compared to SWCNT-COCl, which clearly shows the utility of decorating nanotubes with fluorophore. This research work further extends its application for molecular sensing and other biological process.