Bio-inspired organic-inorganic composite coatings for implants VIA. A micro-dispensing technique

Nano-hydroxyapatite (nHA) and collagen were utilized to fabricate the bio-inspired organic-inorganic composite coating (OICC) via the Drop-on-Demand (DoD) micro-dispensing technique, which could flexibly construct multi-layer structures with varied materials composition within a layer and/or among layers reliably. This technique has been further investigated on its capability of OICC fabrication with regards to various materials (hydroxyapatite and collagen) as well as its dispensing parameters. A four-layered structure was formed, with the sequence of nHA-collagen-nHA-collagen from bottom to top. The dispensing parameters were also investigated with regards to the characteristics of the OICC fabrication. The coating was then subjected to various characterizations including scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS) and adhesion test. SEM and XRD results revealed that the DoD micro-dispensing technique did not change the morphology and phase of these two coating materials. And the results of EDS further demonstrated the corresponding elemental distributions within the four-layered coating structure which demonstrated the feasibility of the DoD micro-dispensing technique for the fabrication of thin-layered OICC.