Human platelet adhesion to pure titanium with different surface treatments

Objective: Platelets are the first cells to adhere to titanium implant surface when the endosseous implants are placed and initially come into contact with blood. The aim of this study was to investigate the initial human platelet adhesion to pure titanium with three different surface modifications-polished surface, dual acid-etched (DAE) surface and sandblasted and acid-etched (SLA) surface. Methods: Commercially pure Ti (cpTi) disks were polished with SiC metallographic paper. Then the disks of three surface modifications were prepared: polished surface, DAE surface and SLA surface. Three disk surfaces were characterized by scanning electron microscopy (SEM). For the platelet study, platelet rich plasma (PRP) was prepared by centrifuging the anti-coagulated blood of healthy human at 150g for 10 minutes. PRP was added to titanium disks in the 24 well plates. 24 well plates were centrifuged and incubated at 37^oC for 20 minutes. The samples were then fixed by 2.5% glutaraldehyde and characterized by SEM. Results: The SLA and DAE surfaces presented more complex microtextures and topography than polished smooth surface. SLA surface presented alveolate or crater texture that was composed of many round micropits. DAE surface showed spinous or tussocky texture, in which micropits were a little smaller. The amount of platelets on SLA and DAE surfaces were much more than that on polished surface. And the amount of platelets on SLA surface was the most. Platelets on polished surface were mainly round and distributed singly and rarely. In the contrast, platelets on SLA and DAE surfaces were wildly distributed and aggregated, but platelets on SLA surface extended pseudopods clearly and linked with each other. Conclusions: Complex rough topography of titanium surface was favourable for the attachment of platelets. SLA surface, which contained macro-rough textures and microtextures, showed better adhesion for initial platelet/titanium interactions.