HePulse 885534J3 Dataset - Soft diamond-like carbon coatings with superior biocompatibility for medical applications: Biomedical applications of diamond-like carbon (DLC) coatings are continuously increasing in recent years. The biocompatibility of DLC coatings has been comprehensively investigated over numerous materials, substrate systems, and dopants but not as a function of DLC intrinsic properties. In this work, a series of DLC coatings are prepared as a function of bias voltage varying from 0 to -120 V, and characterised for their atomic structure, physical, and mechanical properties, and biocompatibility. The contact angle and surface roughness reduce while hardness increases from 7.8 to 20.3 GPa with increasing bias voltage from 0 to -120 V. A relatively soft DLC coating retains its biocompatibility, however, relatively hard DLC coatings present an approaching cytotoxic profiles following exposure of their leached extracts to L929 mouse fibroblast cells. This work will support the correct selection of DLC coatings with an appropriate balance of hardness and biocompatibility for specific biomedical applications.