Thermal Spraying of Fluoresceine-doped HAp coatings

Thermal spraying is a coating technology that is capable of processing high melting materials. More elaborate is the processing of thermally sensitive materials. In joint revision surgery calcium phosphate coatings are applied on metal hip and knee implants to foster ingrowth and ensure a tight connection to the living bone tissue.

The addition of anti-inflammatory drugs is a new approach as it can avoid periprosthetic joint infections. If they occur, a replacement of the implant is inevitable.

In this work, Fluoresceine was used as an organic model to examine if a direct application of thermally sensitive drugs during the spray operation is feasible. It has a similar thermal sensitivity as many antibiotics. However, it can be easily verified due to its fluorescence. If the coating shows fluorescence after spraying it is proven that the Fluoresceine molecule is still intact. By a modification of the spray process, using a two site injection strategy, the agent could be deposited into the HAp coating.