Surface chemistry on PEEK surfaces: From enhanced biofunctionality to improved surface modifiability

• The technologies for introducing functional groups to PEEK surfaces, their advantagesand disadvantages, as well as the gap between laboratory and industry. • Enhanced biofunctions of PEEK by introducing different surface functional groups. • Surface functional groups on PEEK surfaces used for secondary modifications. • Future research directions in PEEK surface modification for clinical translation. Polyetheretherketone (PEEK) has emerged as a promising alternative to traditional metal and ceramic implants in orthopedic and dental applications due to its exceptional mechanical properties and biocompatibility. However, challenges persist in optimizing PEEK implants for load-bearing applications, particularly in achieving adequate osseointegration. Surface modification offers a promising avenue to enhance the PEEK implants’ biofunctions including osseointegration. However, due to the absence of reactive functional groups, PEEK's chemical inertness poses a challenge to its surface modification. Thus, this review comprehensively covers the present physical and chemical treatments aimed at introducing functional groups on PEEK surfaces and discusses the efficacy of various functional groups in enhancing PEEK's biofunctionality and improving its surface modifiability. Insights from this review aim to present various strategies to introduce active functional groups onto PEEK surfaces, providing quick and multiple choices for future researchers studying surface modification on PEEK surfaces.