PEG-SWCNT strongly induces platelet-granulocyte complex formation where the CD63 activation marker can be solely attributed to platelets
János Fent and Susan Lakatos
Department of Pathophysiology, Research Institute, Medical Centre, Hungarian Defence Forces, H-1134 Róbert Károly krt. 44, Budapest, HUNGARY
Nowadays it is widely anticipated that various carbon-based nanotubes have varying platelet activating potential. PEG coated single-wall carbon nanotubes (PEG-SWCNT) are claimed to be biocompatible and gain more and more biomedical applications. Our previous in vitro experiments carried out in human citrated whole blood proved that the pegylated form of SWCNT causes more pronounced platelet activation and whole blood aggregation than its pristine counterpart. According to our recent measurements pegylated SWCNT strongly promotes the platelet-granulocyte complex formation as well. CD63 the lysosomal membrane protein can be found in the dense or in the azurophilic granules of resting platelets and granulocytes, respectively. Surface expression of CD63 indicates release of the above granules. High CD 63 expression was found on platelet-granulocyte complexes which were detected as CD41/CD15 double positive events in the flow cytometer. The presence of single platelets and single granulocytes concomitant with the platelet–granulocyte complexes in our system made possible to reveal that CD63 is originated solely from platelets in the platelet-granulocyte complexes. Consequently, pegylated SWCNT does not induce release of the azurophilic granules of granulocytes.