Response of Human Blood Platelets on Nanoscale Groove Patterns: Implications for Platelet Storage

Understanding platelet–surface activation is of clinical importance because it directly involves the formation of a hemostatic plug or blood clot at sites of vascular injury. Although platelet activation on various structured patterns has been investigated, this behavior on nanoscale groove patterns remains unclear. Here, we fabricated pattern arrays with 100 and 500 nm groove sizes by electron-beam lithography and investigated the response of platelets on these patterns using scanning electron microscopy and atomic force microscopy. Without modification, platelets spread strongest on the unstructured surface and weakest on 100 nm grooves, while the spreading characteristic significantly decreased on laminin-modified surfaces. With a laminin coating, platelets did not spread after contact for 15 min, but the formation of filopodia of different lengths occurred, which is longest on the unstructured surface and shortest on 100 nm grooves. This difference correlated with the adhesion forces because the platelets bound strongest, weaker, and weakest on the corresponding unstructured surface and 500 and 100 nm nanopatterns. Our results show that platelet–surface activation depends on the underlying nanostructured surface, and the findings may have a major impact on medical applications.