*2.3. Preparation of Nanoparticles (NPs)*

The FA–CS NPs were synthesized by ionic cross-linking with tripolyphosphate (TPP) using the method described by Salar and Kumar, 2016, with slight modifications. The FA–CS conjugate solution (0.2%, *w*/*v*, pH 2.5) was prepared using 1% *v*/*v* acetic acid at room temperature. The TPP (0.2%, *w*/*v*) solution in distilled water was prepared. For the synthesis of the 5-FU-loaded nanoparticles, an aqueous solution of 5-FU (500 mg/10 mL) was prepared separately. A solution of 5-FU was added drop-wise into the FA–chitosan conjugate solution. The TPP solution was added into the conjugate solution drop-wise in a 1:3 ratio. The solution was allowed to stir for 1 h on a magnetic stirrer at room temperature. The nanoparticle's suspension was centrifuged at 5000 rpm for 10 min for separating the nanoparticles from the solution, and then freeze-dried for 24 h to obtain the final product of the NPs. NPs without an FA conjugation were also prepared in the same manner.

### *2.4. Characterization*
