Synthesis and characterization of folate conjugated chitosan and cellular uptake of its nanoparticles in HT-29 cells

Folate-chitosan (FA-CS) conjugates synthesized by coupling FA with CS render new and improved functions because the original properties of CS are maintained and the targeting ligand of FA is incorporated. In this work, FA-CS conjugates were synthesized based on chemical linking of carboxylic group of FA with amino group of CS as confirmed by Fourier transform spectroscopy (FTIR) and nuclear magnetic resonance (1H NMR). FA-CS conjugates displayed less crystal nature when compared to CS. The FA-CS nanoparticles (NPs) were prepared by crosslinking FA-CS conjugates with sodium tripolyphosphate (STPP). Positively charged FA-CS nanoparticles were spherical in shape with a particle size of about 100 nm. Cellular uptake of CS or FA-CS nanoparticles was assayed by fluorescent microscopy using calcein as fluorescent marker in colon cancer cells (HT-29). The FA-CS nanoparticles exhibited improved uptake of HT-29 and could become a potential targeted drug delivery system for colorectal cancer.