Copper-doped hydroxyapatite-based coatings for medical applications

The success of an implant depends on its osseointegration, while its long-term survival is determined by its resistance to bacterial infections. Titanium, commonly used for its mechanical properties and corrosion resistance, has limitations regarding its osteointegration and antibacterial efficiency ^[1,2]. The present work's aim is to functionalize the Ti surface with hydroxyapatite doped with copper, known for its antibacterial properties and ability to stimulate bone regeneration.

The coatings were obtained by electrochemical deposition of HAp on Ti and subsequent doping by an ion exchange method with a copper solution. The HAp deposition was carried out in pulsed galvanostatic mode at 75°C from two types of electrolytes: Ca nitrate and Ca chlorate salts. The coatings were characterized in terms of morphology, chemical and phase composition, surface roughness, and thickness. SEM images showed that the HAp coating morphology consists of ribbon-like crystals, irrespective of the electrolyte or the presence of Cu. The EDS analysis highlighted the presence of Cu ions and a (Ca+Cu)/P ratio between 1.54 and 1.59. In terms of coating thickness, it was noted that when chloride salts were used, the thickness was smaller than when nitrates were used. Cu addition to HAp resulted in a slight decrease in thickness, regardless of the electrolyte. XRD analysis confirmed the presence of the HAp phase and HAp coatings successfully doped with Cu.

In conclusion, it can be stated that hydroxyapatite-based coatings obtained through electrochemical techniques can be successfully doped with copper by using the ion exchange method.

[1] F. A. Al-Mulhim, M. A. Baragbah, M. Sadat-Ali, A. S. Alomran, M. Q. Azam, Int Surg 2014, 99, 264.

[2] D. M. Vranceanu, E. Ungureanu, I. C. Ionescu, A. C. Parau, V. Pruna, I. Titorencu, M. Badea, C.-Ștefania Gălbău, M. Idomir, M. Dinu, A. V. (Dragomir), C. M. Cotrut, Biomimetics 2024, 9, 244.