Comparative investigation of the biocompatibility of various silicon nitride ceramic qualities in vitro

Abstract

There is a controversy about the biocompatibility of silicon nitride ceramics contained in the literature, which appears to be related to a factor of the individual chemical composition of different qualities of silicon nitride ceramics and of the different surface properties. This study attempts to investigate the cytotoxicity of different qualities of industrial silicon nitride ceramics applying an L929-cell culture model in a direct contact assay combined with a cell viability assessment. Five different qualities of industrial standard silicon nitride ceramics were chosen for in vitro testing. The chemical composition was determined by EDS analysis. Different biomedically approved aluminium oxide qualities, a titanium alloy, glass and polyvinylchloride (PVC) served as control materials. L929 mice fibroblasts were incubated directly on the materials for 24 h, stained with bisbenzimide and propidium iodine for double fluorochromasia viability testing, and evaluated by inversion-fluorescence microscopy to control cell morphology, viability and cell counts compared to empty well values. Scanning electron microscopy was applied to additionally investigate cell morphology. There was no observation of cytotoxic effects on the silicon nitride ceramic samples; moreover cell morphology remained the same as on aluminium oxide and titanium. Viability testing revealed the presence of avital cells exclusively on PVC, which served as a negative control. Cell counts on all polished surfaces showed significantly higher numbers, whereas some rough surface samples showed significantly lower numbers. We conclude that silicon nitride ceramics show no cytotoxic effects and should be considered for biomedical application owing to its favourable physiochemical properties, especially its superior resistance to mechanical stress, which would be useful for compression loaded conditions. Polished surfaces would appear to promote advanced biocompatibility.

Biocompatibility of nanoporous alumina membranes for immunoisolation

“…The in vitro cytotoxicity test is a standard test that provides information on the interactions between cells and the surface of the material, and is often used as an initial evaluation of biocompatibility [30][31][32]. Here, the viability of cells was evaluated after a 24 hour period, and no significant difference was found between the positive control and the capsules (Figure 4).…”

SiNx Coatings Deposited by Reactive High Power Impulse Magnetron Sputtering: Process Parameters Influencing the Nitrogen Content

“…SiNx is a prospective coating material for metal joint replacements [1][2][3][4][5] ; it is a biocompatible compound 6 with a comparatively high hardness as well as wear resistance. Potential SiNx wear debris dissolves slowly in aqueous solution [7][8] .…”

The Rationale for Silicon Nitride Bearings in Orthopaedic Applications

“…Further investigation compared industrial-grade silicon nitride using the L929-cell culture model, with alumina and titanium alloy as controls. 41 Again, silicon nitride ceramics showed no cytotoxicity and favorable physicochemical properties. Investigators concluded that silicon nitride ceramic should be considered for biomedical applications.…”