Dear Utkarsh,

In general, dye-tagged nanomaterials are achieved using peptide bonding formation. FITC molecule has 'NH2' group in its structure, so you have to prepare the nanomaterials with 'COOH' functionalization. Since this reaction is reversible as hydrolysis, should be done through simple organic chemistry, such as 'EDC/NHS coupling' for firm linkages in DMF, DMSO solvents. There are lots of papers based on above reactions for making X-tagged nanoparticles, you'll gonna find suitable references for your materials and conditions.

If FITC is Fluorescein isothiocyanate, you don't have an amine in the molecule, but an isothiocyanate group (as the proper name indicates) and that will readily react with amines. So you need a NM functionalised with NH or NH2 groups. The reaction works very well in organic solvents in presence of a base (like CH2Cl2 and Et3N) to give an thiourea linkage.

http://onlinelibrary.wiley.com/doi/10.1002/chem.200901149/full

But one thing that you have to be aware of is that FITC fluorescence properties depend on pH and, therefore, they change in different parts of the cells.

http://www.sciencedirect.com/science/article/pii/0014482784906980

For this reason it is not very advisable to employ this tag to perform cellular uptake studies (unless you really want this molecule to take advantage of their pH sensitive properties). For these kind of studies is more appropriate to go for pH independent fluorescent dyes like rhodamines.

http://www.sciencedirect.com/science/article/pii/S0168365910000465

Sorry for misunderstanding of FITC structures. It has a carboxylic group at the corner of benzene ring.