DLC coatings in biomedical applications – Review on current advantages, existing challenges, and future directions

This review explores the intricate realm of DLC (Diamond-like carbon) coatings in biomedical applications, providing a thorough analysis of their biocompatibility and hemocompatibility. The investigation delves into the diverse types of DLC coatings, scrutinizing the influence of their sp3/sp2 ratio and impact of hydrogenation on the coatings' performance. Besides presenting an overview about deposition methods, the application of DLC coatings in orthopedics, tribology, and anti-corrosion within the biomedical context is discussed based upon state-of-the-art literature. The results of the literature survey suggested that DLC-coated joint replacements and prosthetic devices exhibited an improved durability and longevity in orthopedics. Similarly, in cardiovascular interventions, DLC-coated stents demonstrated reduced wear and decreased risk of restenosis thus making them beneficial for applications subject to high mechanical stress and friction. DLC coatings have demonstrated a remarkable biocompatibility with biological tissues, fostering an improved integration and reduced adverse reactions. Moreover, DLC coatings exhibited a notable corrosion resistance enhancing their durability of biomedical devices and implants in physiological environments. Our review does not only illuminate the advancements made but also highlights the challenges encountered in utilizing DLC coatings in biomedical applications, which relates to their robust adhesion to substrate materials, as delamination can compromise the performance and longevity of biomedical devices. Furthermore, there is less information on the long-term stability of DLC coatings in dynamic physiological environments such as joint articulation, which require further studies to ensure sustained performance over the lifespan of biomedical implants.