One-step approach was developed to synthesize amino-reserved chitosan-graft-polycaprolactone (CS-g-PCL) by grafting epsilon-CL oligomers onto the hydroxyl groups of CS via ring-opening polymerization by using methanesulfonic acid as solvent and catalyst. The controllable grafting content of PCL within CS-g-PCL provided the possibility to manipulate the biodegradation rate, hydrophilicity, and hence the cytotoxicity of CS-g-PCL. As a result, the specimen synthesized from the feed molar ratio of glucosamine units in CS vs. epsilon-CL as 1:12 showed equivalent cytotoxicity to the neat CS and PCL against KB cell line, and the cell viability was almost close to 100%. In addition, CS-g-PCL exhibited good solubility in organic solvents, facilitating formation of PCL/CS-g-PCL blend nanofibers via electrospinning with the use of DMF/CHCl(3) as solvent. Owing to the enhanced cellular attachment results from cationic amino groups, it is promising that these copolymers are ideal substances for developing drug carriers and tissue engineering scaffolds. (C) 2009 Elsevier Ltd. All rights reserved.