Table 5.

Advantages and disadvantages of using fibrin, HA, and ELP hydrogels for neural regeneration applications.

Hydrogel Material	Advantages	Disadvantages
Fibrin	Simple gelation scheme that requires the batch combination of fibrinogen and hemostatic enzymes Has innate bioactive entities including multiple integrin receptors and an RGD domain Provides sites for protein attachment, including fibronectin, tPA, and TGFβ	Recruits an inflammatory response which can influence glial scarring and impact neuronal regeneration Often requires extensive purification to remove potential prions Sourced from Mammalia or salmon plasma
Hyaluronic acid	Abundant in the neural ECM and involved in many cellular processes including regeneration and angiogenesis Improves biological activity via non-integrin receptors such as CD44, RHAMM, TLR-2, and TLR-4	Often requires chemical modifications to provide sites for crosslinking Often requires supplementation to enhance growth factor retention and cell-adhesion Expensive and polydisperse
Elastin-like polypeptide	Provides a dynamic polymer with independently tunable parameters Can be produced bearing many bioactive polypeptide motifs Can be produced with enzyme-cleavable therapeutics Provides a facile gelation mechanism via a tunable LCST Cheaply produced with minimal polydispersity and polymorphism	Most often expressed with degradation motifs since elastase is not highly prevalent in neural tissue