Preparation of lysozyme/carbon nanotube hybrids and their interactions at the nano-bio interface

The integration of carbon nanotubes with proteins to form novel hybrid functional assemblies holds great potential application in medical, nanotechnology and materials science. It is still a challenge to verify the interactions between carbon nanotubes (CNTs) and proteins experimentally, including the difficulty of controlling the composition of CNTs and the spatial structure of proteins. In this work, we investigated and compared the different functionalized multi-walled carbon nanotubes (MWCNTs) regarding their interactions with protein, as well as their ability to alter protein structure. Lysozyme (LYZ) was used as the model protein. In addition, the spatial structure of LYZ was changed to further investigate the non-covalent interactions. It was found that the hybrid of CNTs and LYZ still preserved the order of the secondary structure of LYZ. There is hydrogen bonding interaction between them, and different groups grafted on CNTs will affect the strength and site of hydrogen bonding. CNTs may be more bound near Trp 62 and Trp 108, which are mainly responsible for the fluorescence emission of lysozyme. The CNTs/LYZ hybrids presented significant conductivity and higher rigidity, which improves the stability and dispersibility of the hybrid. It may promise a great potential for the application of conductive inks and electronic component printing.