Complement activation by carbon nanotubes.

Carbon nanotube interaction with an important part of the innate immune system, complement, needs to be taken into account when envisaging their use in biomedical applications. Carbon nanotubes (CNTs) and other synthetic materials are recognized by various components of the complement system in human or mammalian blood and also collectins in the lungs. Modification of the surface chemistry of CNTs alters their interactions with complement proteins and collectins. Functionalizations of CNTs which have been tested so far do not completely prevent complement activation or plasma protein binding. The interaction of the functionalized CNTs with the complement system proteins in blood may influence the adhesion of CNTs to phagocytic cells and red blood cells. Excessive activation of complement can have a harmful effect on human tissues and therefore significantly limit CNT applications in biomedicine.