Application of Raman Spectroscopy for Studying the Mechanisms of Neutrophil Activation by Carbon Nanotubes

Raman spectroscopy was used to determine mechanisms for neutrophil activation upon interaction with multi-walled carbon nanotubes (MWCNTs) possessing CO 2 H groups (MWCNTCO 2 H) and in complexes with DNA (MWCNT–CO 2 H/DNA). Short MWCNT–CO 2 H and MWCNT–CO 2 H/DNA (100–300 nm) were found to interact with neutrophils, causing cytoskeleton reorganization, namely, activation of G-actin to give F-actin in cells. Raman spectroscopy showed that these CNTs are not phagocytized by neutrophils. MWCNT–CO 2 H enhances the generation of reactive oxygen and chlorine species by neutrophils as indicated by an increase in the NADPH–oxidase activity in a cell suspension. The interaction of MWCNT–CO 2 H/DNA leads to inhibition of the oxygen-activating ability of phagocytes and formation of neutrophilic extracellular traps (NET) with the inclusion of carbon nanostructures. The free radical products generated by neutrophils disrupt the crystal structure of MWCNTs.