Surface functionalization of polycaprolactone-based biomaterials: Good practice and pitfalls

Poly(ɛ-caprolactone) (PCL) remains widely studied in biomaterials science and biomedical engineering due to its versatility and applicability in regenerating a range of tissues including bone, cartilage, neural, and cardiovascular. Due to the hydrophobicity of PCL, most PCL based systems for tissue regeneration require a surface modification process to enhance its in vitro and in vivo compatibility. This Perspective aims to provide an overview of recent strategies used to modify 2D films and 3D scaffolds and the associated methods used to characterize these surfaces. The scope is restricted to physical and chemical postmodification methods, excluding blends and composites, to better isolate the effects of surface chemistry. By analyzing the latest studies (published in 2022-2024), we classified the most commonly employed surface modification techniques, and we identified that the surface evaluation of tailored PCL remains a critical challenge in terms of both chemical and morphological characterization as well as the stability of the introduced surface layer/coating. This status of recent literature highlights current excellent practices and characterization methodologies and suggests approaches for refining surface engineering methods of PCL-based biomaterials in the future.