Fabrication of bioactive 3D printed porous titanium implants with Sr ion-incorporated zeolite coatings for bone ingrowth.

Functionalization of porous titanium alloy implants with bioactive coatings to improve bone regeneration performance is hotly pursued in recent decade. Here we demonstrate a facile strategy to design bioactive 3D printed porous titanium implants with strontium (Sr) ion incorporated zeolite coatings (SZCs). The SZCs can be uniformly fabricated on the 3D porous scaffolds using an in situ hydrothermal crystal growth method to improve their osteogenesis and osteointegration capacity. In vitro experiments of SZCs on a TC4 disk show that Sr ions can slowly release in the simulated body fluid by means of ion-exchange, thus can drastically improve apatite forming ability, biocompatibility, corrosion resistance, and alkaline phosphatase (ALP) activity. In vivo evaluation on a rabbit model with 3D printed titanium implants shows that the SZCs could significantly induce new bone formation both in and around the porous implants within four weeks. This work may open up a new method for the development of bioactive customized porous implants by functionalization with zeolite coatings for orthopedic applications.