Recent Trends in the Development of Peptide and Protein-based Hydrogel Therapeutics for Healing of CNS Injury

Traumatic brain injury (TBI) and spinal cord injury (SCI) causes millions of death and permanent or prolonged physical disabilities around the globe every year. It generally happens due to various incidents, such as accidental, during sports, during war or physical assault, stroke, etc. related injury, which resulted in severe damages in the brain and spinal cord. If remain untreated, traumatic CNS injuries may lead to the early development of several neurodegenerative diseases like Alzheimer’s, Parkinson, Multiple Sclerosis, and other mental illnesses. The initial physical reaction, which is also termed as primary phase includes swelling followed by inflammation as a result of internal haemorrhage causing damage to indigenous tissue i.e., axonal shear injury, rupture of blood vessels, and partially impaired supply of oxygen and essential nutrients in the neurons thereby initiating the cascade of events causing secondary injuries such as hypoxia, hypotension, cognitive impairment, seizures imbalanced calcium homeostasis and glutamate-induced excitotoxicity resulting concomitant neuronal cell death and cumulative permanent tissue damage. At present, in this era of advanced biomedical technology, we are still living in the scarcity of any clinically applicable comparatively non-invasive therapeutic strategy for regenerating or functional recovery of neurons or neural networks after a massive CNS injury. One of the key reasons is the limited regenerative ability of neurons in CNS. Growth impermissive glial scar and the lack of a synthetic biocompatible platform for the proper neural tissue engineering and controlled supply of drugs further retard the healing process. Injectable or implantable hydrogel materials, consisting majority of water in its porous three-dimensional (3D) structure, can serve as an excellent drug delivery platform as well as a transplanted cell supporting scaffold medium. Among various neuro-compatible bioinspired materials, we are limiting our discussion focusing upon the recent advancement of engineered biomaterials comprising mainly peptides and proteins due to their growing demand low immunogenicity and versatility in the fabrication of neuro regenerative medicine. In this article, we tried to explore all the recent scientific avenues, which are developing gradually to make peptide and peptide conjugated biomaterial hydrogels as a therapeutic as well as supporting scaffold for treating CNS Injury.