A detailed method for copper doping of synthetic hydroxyapatite thin films via plasma-assisted pulsed laser deposition

This work provides a detailed and reproducible methodology for the fabrication of copper-doped hydroxyapatite (HAp-Cu) thin films on silicon substrates via Plasma-Assisted Pulsed Laser Deposition (PAPLD). The methodology is centered on the nanosecond pulsed laser ablation of a synthetic hydroxyapatite (HAp) target, physically modified through the incorporation of metallic copper filaments, which serve as a localized dopant source during the deposition process. This configuration enables the controlled co-deposition of hydroxyapatite and copper species, facilitating the formation of uniform thin films with potential bioactive properties. The proposed protocol comprises the following key elements: • Preparation of Targets: A comprehensive, stepwise procedure for the synthesis of hydroxyapatite powder and the subsequent fabrication of mechanically robust ceramic targets, including a novel approach for embedding copper filaments to ensure effective doping during laser ablation. • Deposition Parameters: Detailed specifications of the PAPLD system, encompassing laser characteristics (wavelength, fluence, repetition rate), target-to-substrate distance, and chamber vacuum conditions. These parameters have been optimized to ensure reproducibility in film growth and compositional consistency. • Validation Procedure: A systematic approach to validating the deposition process, focused on confirming the incorporation of copper into the hydroxyapatite matrix and verifying the formation of crystalline HAp-Cu films through targeted characterization techniques, distinct from exhaustive physicochemical or biological evaluations. The methodology described herein establishes a reliable framework for the fabrication of HAp-Cu coatings via PAPLD, offering a reproducible route for future studies requiring precise control over dopant incorporation within hydroxyapatite-based thin films. For further details regarding the physicochemical characterization and biological assessment of the resulting coatings, the reader is referred to a complementary publication by the authors.