A simple method for preparing biocompatible composite of cellulose and carbon nanotubes for the cell sensor

The composite of cellulose (CL) and carbon nanotubes (SWNTs), which combined the biocompatibility of the former and the conductivity of the latter, was prepared using the room temperature ionic liquid (RTIL) as intermediary solvent. CL was dissolved in the RTIL, and SWNT was dispersed in this solution, and then RTIL was removed to form CL–SWNT composite. 1-Butyl-3-methylimidazolium acetate ([bmim][OAc]) was chosen as the RTIL due to its excellent solubility for cellulose, which in turn improved the homogeneity of CL–SWNT composite. The composite was utilized for immobilizing leukemia K562 cells on a gold electrode to form an impedance cell sensor. The sensor for leukemia K562 cells showed a linear range from 1.6 × 104 to 1.0 × 107 cells mL−1 with a detection limit of 2.6 × 103 cells mL−1 according to 3σ rule.