Anticorrosion and biocompatible zeolite based coatings for tissue regeneration on metallic bioimplants

Increasing healthcare costs are adversely affecting the quality of life in modern society, but they are a driving force for innovation in medical technology. Dental and orthopedic implants are routinely used to repair damaged bone tissue, but biocompatible materials used for implants have amplified the cost of obtaining treatment. Expensive materials and processing steps are required to obtain enhanced corrosion resistance and biocompatibility. More cost effective implant materials would allow a greater percentage of the population to receive treatment. Zeolite coatings have been synthesized on various metallic substrates for corrosion protection, but their application to metallic implant materials had not been investigated before. The goal of this research is to apply zeolite coatings to commercial titanium alloys and stainless steels for corrosion protection, and to determine the biocompatibility of zeolite based coatings for applications towards biomedical implants.;Zeolite based coatings proved to be good scaffolds for bone growth. To enhance biocompatibility of zeolite coatings, a composite zeolite-hydroxyapatite coating was developed. Synthesis of the composite coating was carried out using a multi-step process. The coatings were characterized by scanning electron microscopy (SEM), x-ray diffraction (XRD), energy dispersive x-ray spectroscopy (EDS), and biochemical studies were performed to test the adhesion, proliferation and differentiation of osteoblasts. Mechanical properties of the composite coatings, such as their hardness and modulus, were engineered to match those of bone in order to enhance osteointegration of implants. Zeolite based coatings proved to be highly corrosion resistant and prevented the leaching of toxic metallic ions into the surrounding environment, which could enhance the implant lifespan.;Zeolite coatings sustained the growth of stem cell colonies better than glass substrates, indicating their high biocompatibility. Moreover, we showed that zeolite coating prevented delamination of newly formed bone tissue as compared to bare metal surface. Gene expression analysis showed a six to eight fold increase in Bone Morphogenetic Protein 2 (BMP2) as compared to bare Ti6Al4V and SS316L, which resulted in faster differentiation of human fetal osteoblasts into adult osteoblasts. Zeolite based coatings on steel instead of titanium implants can reduce cost and post-surgical recovery time for patients receiving orthopedic implants.