Intelligent temperature-pH dual responsive nanocellulose hydrogels and the application of drug release towards 5-fluorouracil

As the typical bio-macromolecules, cellulose and its derivates are widely studied due to the fact that they are green and renewable resources in nature. In this work, intelligent temperature-pH sensitive nanohydrogels consisting of nanocellulose, thermal responsive monomer (N-isopropylacrylamide, NIPAM), and pH responsive monomer (acrylic acid, AA; acrylamide, AM) were prepared [NFC-g-(AA/AM)]-g-NIPAM, the [NFC-g-(AA/AM)]-g-NIPAM was characterized by FTIR, scanning electron microscope (SEM), thermogravimetric analysis (TGA) and automatic gas adsorption analysis (BET). The results showed that the copolymerization of AA, AM and NIPAM were carried out successfully. The specific surface area, total pore volume, average pore diameter and thermal stability of the modified nano-cellulose were increased. In addition, the as-prepared nanohydrogels with 5-fluorouracil (5-FU) released more 5-FU at 40 °C and acidic condition compared to the room temperature and neutral pH, showing the characteristics of the temperature-PH dual response functionalization. The [NFC-g-(AA/AM)]-g-NIPAM have been proved to be the promising drug release nanohydrogels towards 5-FU, and the valuable findings might provide an idea for maximizing the potential of the nanocellulose-based nanohydrogels for the application of environmental pollution control.