Polymer and nano-technology applications for repair and reconstruction of the central nervous system

The hydrophilic polymer PEG and its related derivatives, have served as therapeutic agents to reconstruct the phospholipid bilayers of damaged cell membranes by erasing defects in the plasmalemma. The special attributes of hydrophilic polymers when in contact with cell membranes have been used for several decades since these well-known properties have been exploited in the manufacture of monoclonal antibodies. However, while traditional therapeutic efforts to combat traumatic injuries of the central nervous system (CNS) have not been successful, nanotechnology-based drug delivery has become a new emerging strategy with the additional promise of targeted membrane repair. As such, this potential use of nanotechnology provides new avenues for nanomedicine that uses nanoparticles themselves as the therapeutic agent in addition to their other functionalities. Here we will specifically address new advances in experimental treatment of Spinal Cord and Traumatic Brain injury (SCI and TBI respectively). We focus on the concept of repair of the neurolemma and axolemma in the acute stage of injury, with less emphasis on the worthwhile, and voluminous, issues concerning regenerative medicine/nanomedicine. It is not that the two are mutually exclusive - they are not. However, the survival of the neuron and the tissues of white matter are critical to any further success in what will likely be a multi-component therapy for TBI and SCI. This review includes a brief explanation of the characteristics of traumatic spinal cord injury SCI, the biological basis of the injuries, and the treatment opportunities of current polymer-based therapies. In particular, we update our own progress in such applications for CNS injuries with various suggestions and discussion, primarily nanocarrier-based drug delivery systems. The application of nanoparticles as drug-delivery vehicles to the CNS may likely be advantageous over existing molecular-based therapies. As a "proof-of-concept", we will discuss the recent investigations that have preferentially facilitated repair and functional recovery from breaches in neural membranes via rapid sealing and reassembly of the compromised site with silica or chitosan nanoparticles.