Purpose
Titanium framework keratoprosthesis (Ti-KPro), as a synthetic artificial cornea has provided an option to the severe corneal blindness, but the bioactive of skirt material remained to be improved. The purpose of this study was to evaluate the effect of the novel biomaterial, nano-structural hydroxyapatite coated titanium (nHAp-Ti) on the material-cellular interaction in vitro and to assess the integration of nHAp-Ti in vivo.
Methods
HAp was coated on the surface of pure-titanium through a novel coating technique, aerosol deposition (AD) method. The topography of the coatings was investigated with scanning electron microscopy (SEM). The rabbit cornea fibroblast (RCFB) was used to investigate the cytocompability. Cell morphology was studied using SEM, and cell proliferation was analyzed by MTT at different time point. Cell migration was studied by scratch wound assay. The expression of integrin β4 was studied by reverse transcription polymerase chain reaction (RT-PCR) and flow cytometry. In vivo test, the samples were implanted into healthy rabbit cornea and followed up by anterior segment optical coherence tomography(AS-OCT) for 12 weeks.
Results
The SEM micrographs of nHA coating presented grain-like appearance, while the surface of the bare-Ti showed a rigid metallic surface (Figure 1). The morphological images by SEM showed most cells on Ti surface were slim, shuttle-shaped morphology, while cells on the nHA modified surfaces were well spread and showed elongated, flattened morphology. The outcomes of MTT displayed that an obvious proliferation of cells on the two different surfaces. The scratch wound assay showed cells on the nHA surface sealed wounds faster than that of bare-Ti at 24 h (Figure 2). Also, the high level of integrin β4 expression was illustrated on the nHAp-coated surface by RT-PCR and flow cytometry. In the animal model, nHAp-Ti implants were stably retained in the rabbit cornea, however the corneal stroma anterior to the implants became thinner in the control.
Conclusions
Our findings indicated that the surface composition and topography have a significant effect on the biocompatibility of implant. HA-Ti can improve the cell activity in vitro as well as the tissue integration in vivo.
Keywords: 575 keratoprostheses •
480 cornea: basic science •
607 nanotechnology