Polyethylenimine-grafted cellulose nanofibril aerogels as versatile vehicles for drug delivery.

Aerogels from polyethylenimine-grafted cellulose nanofibrils (CNFs-PEI) were developed for the first time as a novel drug delivery system. The morphology and structure of the CNFs before and after chemical modification were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). Water-soluble sodium salicylate (NaSA) was used as a model drug for the investigation of drug loading and release performance. The CNFs-PEI aerogels exhibited a high drug loading capability (287.39 mg/g), and the drug adsorption process could be well described by Langmuir isotherm and pseudo-second-order kinetics models. Drug release experiments demonstrated a sustained and controlled release behavior of the aerogels highly dependent on pH and temperature. This process followed quite well the pseudo-second-order release kinetics. Owing to the unique pH- and temperature-responsiveness together with their excellent biodegradability and biocompatibility, the CNFs-PEI aerogels were very promising as a new generation of controlled drug delivery carriers, offering simple and safe alternatives to the conventional systems from synthetic polymers.