Active implants · Engineering microstructures of functional ceramics for stimulated bone growth

Active implants: Engineering microstructures of functional ceramics for stimulated bone growth

Replacement surgeries for bone tissue are a normal part of clinical practices nowadays with constantly increasing numbers for e.g. hip and knee joint replacements. However, such procedures are still a substantial intervention and afflicted with long healing times reducing the patient’s quality of life and generating high costs for the health care system. Thus, it is very desirable to develop implant materials that accelerate the healing process and support the development of a long lasting functional interface between bone and implant. For load-bearing bone it is well known that the application of mechanical stress leads to the creation of electric potentials, which serve as electric stimuli to trigger bone and vascular cell growth. Thus, the creation of stress generated electric potentials by the implant material mimicking this electric trigger for cell growth has the potential to accelerate the healing process and to improve the bone-implant bonding. Piezoelectric materials are potential candidates for this purpose, as they develop electric surface charges under mechanical load similar to load-bearing bone. The quality of the final bone-implant interface is determined by thes biocompatibility of the replacement material, its surface morphology and electric surface states. Especially the porosity of the ceramic is of crucial importance as the pores have to be large enough and of open structure to allow ingrowth of both bone and vascular cells. However, increasing porosity is alters the piezoelectric behaviour and by this the surface charges responsible for cell growth stimulation. The main research objective was to clarify the relationship between microstructure and piezoelectric behaviour of different piezoelectric ceramics. The knowledge gained forms the basis for the development of a new class of implant materials exploiting the piezoelectric characteristics to improve the healing process. Three different types of piezoelectric ceramics were successfully made. The piezoelectric performance of all material systems decreased with increasing porosity, but remained higher than the natural response of cortical bone. This makes them promising as porous bone implant materials. Two of the base systems exhibit highly stable performance even after long submersion in salt solution – simulating the state within the body. The third base system disintegrates when placed in salt solution. However, this process can be controlled, which makes this class of material promising as bioresorbable implant option.

Текст от CORDIS, на английски · Данни: CORDIS, © Европейски съюз