An electro-active biopolymer actuator based on the bacterial cellulose was newly developed to be activated in the wet environment for biomedical applications. When bacterial cellulose (BC) membranes with biocompatibility and biodegradability were electrically activated under fully hydrated condition, the bending deformations were observed for both step and harmonic electrical input signals. The LiCl treated bacterial cellulose was used to improve the bending actuation performance due to much larger ion migration. XRD, TGA, DSC, tensile test, IEC and ionic conductivity of the LiCl treated bacterial cellulose were compared with those of pristine bacterial cellulose. The electromechanical performances of LiCl treated BC show much large bending deformation because of its lower stiffness and higher ionic exchange capacity through the proper control of crystallinity. Also, the surface modification that affects the adhesion between the gold electrode and the bacterial cellulose surface was observed in the SEM images after LiCl treatment. Present results show that the bacterial cellulose actuator can be a promising smart material that may possibly be used in the wet environment of diverse biomedical applications. (c) 2010 Elsevier B.V. All rights reserved.