SiNtx Technologies Inc (SINT)

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Bacteriostatic behavior of surface modulated silicon nitride in comparison to polyetheretherketone and titanium

The various Si3 N4 samples showed the most favorable bacterial resistance for both bacilli tested. The mechanisms for the bacteriostatic behavior of Si3 N4 are likely due to multivariate surface effects including submicron-topography, negative charging, and chemical interactions which form peroxynitrite (an oxidative agent). Si3 N4 is a new biomaterial with the apparent potential to inhibit biofilm formation.

Antifungal activity of polymethyl methacrylate/Si3N4 composites against Candida albicans

Previous studies using gram-positive and -negative bacteria demonstrated that hydrolysis of silicon nitride (Si3N4) in aqueous suspensions elutes nitrogen and produces gaseous ammonia while buffering pH. According to immunochemistry assays, fluorescence imaging, and in situ Raman spectroscopy, we demonstrate here that the antipathogenic surface chemistry of Si3N4 can be extended to polymethylmethacrylate (PMMA) by compounding it with a minor fraction (~8 vol.%) of Si3N4 particles without any tangible loss in bulk properties. The hydrolytic products, which were eluted from partly exposed Si3N4 particles at the composite surface, exhibited fungicidal action against Candida albicans.

https://www.sciencedirect.com/science/article/abs/pii/S1742706121001641

Silicon Nitride as a Biomedical Material: An Overview

Considering its unique combination of properties, silicon nitride shows great potential for applications from both a basic research point of view and an industrial perspective. Si3N4 is a promising candidate for orthopedic implants due to its high strength, artifact-free imaging, and bio-responsiveness. It has several advantages over other commonly used biomaterials. For example, Si3N4 has a higher compressive strength than metallic biomaterials such as titanium and cobalt-chromium alloys, or biopolymers such as PEEK and UHMWPE, and a higher fracture toughness than some oxide bioceramics such as alumina. In addition to high fracture toughness, Si3N4 has a high wear resistance and a low coefficient of friction. Compared to metal implants, which produce radiological artifacts on CT or MRI scans, and PEEK, which is radiolucent, Si3N4 has favorable imaging properties and is free of artifacts on standard imaging techniques such as MRI or CT. In addition, compared to PEEK and titanium, the particular surface chemistry of Si3N4 in an aqueous environment leads it to promote bone tissue healing but inhibit bacterial proliferation. However, Si3N4 still has some disadvantages, such as brittleness, low energy dissipation, and high manufacturing cost. Currently, Si3N4 is already being used in arthrodesis devices in the cervical and thoracolumbar spine, and it is under consideration for approval in the joint arthroplasty and dental fields. Scientists and engineers have made great strides in expanding the use of Si3N4 for clinical applications and addressing various issues being faced by the industry today. Si3N4 has the potential to be microstructurally engineered and adapted to many applications, e.g., by grain size and morphology, grain boundary phase, or in a composite. We expect that further innovation of Si3N4 will come soon.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9224221/