writer：Liman Hou, Jianyong Fang, Weiqi Wang, Zhigang Xie, Dewen Dong and Ning Zhang*
keywords：Bottle-brush brushes, poly(2-oxazoline)s, ICG, CNC, photothermal cancer therapy
source：期刊
specific source：J. Mater. Chem. B
Issue time：2017年
Deriving from the most abundant and renewable material, cellulose nanocrystals (CNCs) have drawnincreasing  attention  in  nanomedicine  as  well  as  other  biomedical  fields  due  to  their  excellentphysicochemical properties and unique rod-like geometry. In this work, we report an efficient procedureto create biocompatible poly(2-oxazoline)s with a defined bottle brush architecture on CNCs throughUV-induced  photopolymerization  and  subsequent  living  cationic  ring-opening  polymerization.Characterization of the poly(2-oxazoline) modified CNCs indicates an improved thermal stability with thecrystalline structure as well as the rod-like contour intact. The side chain terminal piperidinium ofthe bottle brush was utilized to immobilize indocyanine green (ICG)viaelectrostatic interactions. Theresulting nanorods exhibit low toxicity in the dark and an efficient photothermal therapeutic effectagainst HeLa cells under 808 nm near infrared laser irradiation after being internalized by cancer cells.Moreover, bottle brushes on CNCs with amphiphilic poly(2-n-propyl-2-oxazoline) side chains show ahigher efficiency in stabilizing ICG in comparison to those with hydrophilic poly(2-methyl-2-oxazoline)side chains, thus a higher photostability and a greater therapeutic effect were revealed for amphiphilicpolymer modified CNCs. This work indicates that poly(2-oxazoline) functionalized CNCs represent anovel and promising platform for the design of other CNC-based drug delivery systems.