Antioxidants are a class of molecules with an innate affinity to neutralize reactive oxygen species (ROS), which are known to cause oxidative stress. Oxidative stress has been associated with a wide range of diseases mediated by physiological damage to the cells. ROS play both beneficial and detrimental roles in human physiology depending on their overall concentration. ROS are an inevitable byproduct of the normal functioning of cells, which are produced as a result of the mitochondrial respiration process. Since the establishment of the detrimental effect of oxidative stress in neurological disorders and neurotrauma, there has been growing interest in exploring antioxidants to rescue remaining or surviving cells and reverse the neurological damage. In this review, we present the survey of different antioxidants studied in neurological applications including neurotrauma. We also delve into bioengineering approaches developed to deliver antioxidants to improve their cellular uptake in neurological applications.

Three-dimensional (3D) bioprinting has made it possible to fabricate structures with intricate morphologies and architectures, which is considered difficult to do when using other conventional techniques like electrospinning. Although the 3D printing of thermoplastics has seen a huge boom in the past few years, it has been challenging to translate this technology to cell-based printing. A major limitation in bioprinting is the lack of inks that allow for the printing of 3D structures that meet the biological requirements of a specific organ or tissue. A bioink is a viscous polymer solution that cells are incorporated into before printing. Therefore, a bioink must have specific characteristics to ensure both good printability and biocompatibility. Despite the progress that has been made in bioprinting, achieving a balance between these two properties has been difficult. In this work, we developed a multimodal bioink that serves as both a cell carrier and a free radical scavenger for treating peripheral nerve injury. This bioink comprises poly(vinyl alcohol) (PVA) and cerium oxide nanoparticles (also called nanoceria (NC)) and was developed with a dual crosslinking method that utilizes citric acid and sodium hydroxide. By employing this dual crosslinking method, good printability of the bioink and shape fidelity of the bioprinted structure were achieved. Additionally, a cell viability study demonstrated that the cells remained compatible and viable even after they underwent the printing process. The combination of this PVA/NC bioink and the dual crosslinking method proved to be effective in enhancing printability and cell biocompatibility for extrusion-based bioprinting applications.