One-step esterification of nanocellulose in a Brønsted acid ionic liquid for delivery to glioblastoma cancer cellsElectronic supplementary information (ESI) available: Characterization of N-methylpyrrolidinium hydrogen sulfate. See DOI: 10.1039/c7nj04633b

The Fisher esterification reaction has been exploited for linking a peptide (chlorotoxin) onto the surface of nanocellulose using a Brønsted acid ionic liquid both as a solvent and a catalyst. Indeed, cellulose nanocrystals were functionalized with the peptide thanks to a mild, one-step and organic solvent-free reaction. The obtained nanocellulose showed excellent properties in terms of biocompatibility and internalization in the U87MG glioblastoma cell line, thus demonstrating the possible use of this material as a novel drug delivery carrier. A Brønsted acid ionic liquid used as a solvent and a catalyst allows easy and mild esterification of nanocellulose with a chlorotoxin peptide.