Bone cell responses to ion-implanted titanium
Among the various surface modification techniques developed to improve the biocompatibility of titanium (Ti), ion-implantation is a method which can alter Ti surface chemistry in a relatively controlled manner. Although implantation of Ti surfaces with calcium (Ca) ions has previously been shown to enhance osseointegration in vivo, the underlying mechanisms responsible for such responses still remain unclear. The aim of the current study was, therefore, to examine the precise effects of ion-implanted Ti on human bone cells by assessing a range of biological activities in vitro. Ca, potassium (K) and argon (Ar) ions were selected to be implanted. Although similar in mass, chemically they are quite different, which was reflected in the differential response of bone cells. Thus, Ti surfaces implanted with 1 x 1017 cm"2 Ca ions reduced cell adhesion at 4 h, but, nevertheless, significantly increased cell spreading and subsequent growth compared with the (non-implanted) Ti control. In contrast, cells on K-Ti responded in a very similar manner as the control, whereas cells on the Ar- implanted Ti appeared less flattened and did not grow well.