Current sustained delivery strategies for the design of local neurotrophic factors in treatment of neurological disorders

Although therapeutic potential of neurotrophic factors (NTFs) has been well recognized for over two decades, attempts to translate that potential to the clinic have been disappointing, largely due to significant obstacles in delivery, including inadequate protein dose/kinetics released at target sites. Considerable efforts have been made to improve the therapeutic performance of NTFs. This articles reviews recent developments in localized delivery systems of NTFs for the neurological disorders treatments with a main focus on sustained delivery strategies. Different non-covalent binding approaches have been employed to immobilize proteins in hydrogels, microspheres, electrospun nanofibers, and their combined systems, which serve as depots for sustained local release of NTFs. The challenges associated with current NTFs delivery systems and how these systems can be applied to neurological diseases and disorders have been discussed in the review. In conclusion, optimal delivery systems for NTFs will be needed for reliable and meaningful clinical benefits; ideally, delivering a time and dose-controlled release of bioactive multi-NTFs at different individual optimal kinetics to achieve multi-functions in target tissues is significant preferred.