Research progress of hydrogels as delivery systems and scaffolds in the treatment of secondary spinal cord injury

Abstract

Secondary spinal cord injury (SSCI) is the second stage of spinal cord injury (SCI) and involves vasculature derangement, immune response, inflammatory response, and glial scar formation. Bioactive additives, such as drugs and cells, have been widely used to inhibit the progression of secondary spinal cord injury. However, the delivery and long-term retention of these additives remain a problem to be solved. In recent years, hydrogels have attracted much attention as a popular delivery system for loading cells and drugs for secondary spinal cord injury therapy. After implantation into the site of spinal cord injury, hydrogels can deliver bioactive additives in situ and induce the unidirectional growth of nerve cells as scaffolds. In addition, physical and chemical methods can endow hydrogels with new functions. In this review, we summarize the current state of various hydrogel delivery systems for secondary spinal cord injury treatment. Moreover, functional modifications of these hydrogels for better therapeutic effects are also discussed to provide a comprehensive insight into the application of hydrogels in the treatment of secondary spinal cord injury.

Biomaterials targeting the microenvironment for spinal cord injury repair: progression and perspectives

“…The scaffolds must also incorporate trophic factors, cells, agents, and other relevant components. Furthermore, the scaffolds should possess the ability to direct axon development and facilitate cell proliferation ( Peng et al, 2023 ). Scaffold materials must offer an optimal milieu for the processes of cell adhesion, proliferation, and differentiation.…”

“…Hydrogel is a type of biomaterial that has properties akin to those of gelatinous substances. Its primary purpose is to facilitate medication and cell transportation ( Peng et al, 2023 ). Hydrogel exhibits favorable injectability and recoverability, rendering it suitable for administering chemicals to facilitate SCI healing.…”

Hydrogel scaffolds in the treatment of spinal cord injury: a review

“…In the tissue engineering for the treatment of SCI, the role of hydrogels mainly includes the following points: Firstly, hydrogels provide three-dimensional spatial support for neuronal regeneration and axonal extension, which is conducive to cell growth, proliferation and migration and promotes neural reconstruction ( Chedly et al, 2017 ; Silva et al, 2023 ). Secondly, the hydrogel itself act as a carrier to load stem cells to the site of injury, reducing cell loss to surrounding tissues and off-targeting ( Peng et al, 2023 ). Thirdly, hydrogels slowly release bioactive factors or chemical drugs to achieve a sustained and stable release for better performance ( Luo et al, 2021 ; Figure 2 ).…”

Macrophage Membrane-Coated MnO2 Nanoparticles Provide Neuroprotection by Reducing Oxidative Stress after Spinal Cord Injury

“…Spinal cord injury (SCI) is a major medical condition worldwide, often resulting in motor dysfunction and chronic pain syndromes. , Approximately one million people worldwide have been reported to suffer from SCI-related disorders each year, with traumatic contusions being the most common. , Traumatic SCI includes primary injury and secondary injury . Many studies have reported that secondary injury is an important stage in the treatment of SCI. , Timely therapeutic intervention can inhibit the progression of secondary injury and have a significant impact on long-term neurological and functional recovery . The spinal cord microenvironment in the secondary injury phase produces large amounts of reactive oxygen species (ROS) (e.g., H 2 O 2 ). , The ROS cannot be metabolized in a timely manner and form accumulation, leading to local ischemia, hypoxia, and inflammatory cascade response .…”

“…6,7 Timely therapeutic intervention can inhibit the progression of secondary injury and have a significant impact on long-term neurological and functional recovery. 8 The spinal cord microenvironment in the secondary injury phase produces large amounts of reactive oxygen species (ROS) (e.g., H 2 O 2 ). 9,10 The ROS cannot be metabolized in a timely manner and form accumulation, leading to local ischemia, hypoxia, and inflammatory cascade response.…”