EAGER: Biocompatibility of nanocrystalline YSZ transparent cranial implant

University Of California-Riverside, Riverside CA

Investigators

Abstract

NON-TECHNICAL DESCRIPTION: The overall goal of this project is to develop a new generation of transparent ceramics, which may be used to replace traditional, opaque cranial implants (made from titanium and polymer-based materials). This new implant, which is referred to as a Window to the Brain (WttB) platform, allows for non-invasive optical interrogation of the brain on a recurring basis and, thus, serves as a critical enabler of emerging laser-based diagnostic (e.g., optogenetics) and therapy (e.g., photodynamic therapy) of brain pathologies and neurological disorders, such as brain cancer, stroke, traumatic brain injury, Parkinson's disease, etc. In particular, this project focuses on assessing potential problems of low temperature "ageing" and biofilm formation around the ceramic implant. The broad impact of this project lies in the added benefit it provides to the neuroscience community, which aims to advance understanding and improve brain disease management, thus improving quality of life and reducing healthcare costs. Furthermore, the advances made in the science and technology of novel opto-ceramic materials such as this has potential to extend to numerous other fields, including medical lasers, defense, energy, etc. This project also provides research opportunities to undergraduate and graduate students, particularly in the STEM field and for underrepresented minorities, preparing them to innovate as independent, globally-engaged engineers. TECHNICAL DETAILS: While traditional cranial implant materials provide the mechanical properties and acceptable biocompatibility necessary after implantation, none provide the unique combination of high fracture toughness and optical transparency that would enable physicians to diagnose and treat continuously various brain pathologies and neurological disorders. A recent feasibility study of a transparent nanocrystalline yttria-stabilized-zirconia (nc-YSZ) on an animal model showed that non-invasive optical interrogation of the brain is possible. Since aging-induced degradation has been reported in other types of YSZ implants as a result of phase change destabilization, independent assessments of a similar kind are required for transparent nc-YSZ materials. Furthermore, the optical transparency of these implants allows for laser-mediated controls to arrest and even revert excessive fouling (biofilm formation), which is another potential impediment for the use of this material for biomedical applications such as this. Therefore, the first goal of this project is to investigate if long term ageing could limit the use of transparent nc-YSZ as a medical material. The second goal is to measure the extent of biofilm formation on nc-YSZ samples and explore the use of sub-therapeutic laser irradiation approaches to remedy such a problem if it arises. The significance of this work lies in the potential of the ceramic-based WttB platform which may eventually allow advancements in the understanding of the brain, by facilitating the clinical translation of emerging optogenetic neurotechnologies. This research is timely and transformational and falls under the objectives of the BRAIN Initiative. As well, it is providing research opportunities to undergraduate and graduate students. This project is leveraging well-established programs and student organizations such as the California Alliance for Minority Participation (CAMP), UC Leadership Excellence through Advanced Degrees (UC LEADS), and the Society for Hispanic Professional Engineers (SHPE).