Ionic liquids-based processing of electrically conducting chitin nanocomposite scaffolds for stem cell growth

Abstract

In the present study, we have successfully combined the biocompatible properties of chitin with the high electrical conductivity of carbon nanotubes (CNTs) by mixing them using an imidazolium-based ionic liquid as a common solvent/dispersion medium. The resulting nanocomposites demonstrated uniform distribution of CNTs, as shown by scanning electron microscopy (SEM) and optical microscopy. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction confirmed the α-crystal structure of chitin in the regenerated chitin nanocomposite scaffolds. Increased CNT concentration in the chitin matrix resulted in higher conductivity of the scaffolds. Human mesenchymal stem cells adhered to, and proliferated on, chitin–CNT nanocomposites with different ratios. Cell growth in the first 3 days was similar on all composites at a range of (0.01 to 0.07) weight fraction of CNT. However, composites at a 0.1 weight fraction of CNTs showed reduced cell attachment. There was a significant increase in cell proliferation using 0.07 weight fraction CNT composites, suggesting a stem cell enhancing function for CNTs at this concentration. In conclusion, the ionic liquid allowed the uniform dispersion of CNTs and dissolution of chitin to create a biocompatible, electrically conducting scaffold permissive for mesenchymal stem cell function. This method will enable the fabrication of chitin-based advanced multifunctional biocompatible scaffolds where electrical conduction is critical for tissue function.