Hyaluronic acid-poly hydrogel

To mimic the macromolecular-based ECM in biological tissue, the cell adhesion and proliferation properties of hydrogels are critical parameters. However, various hydrogels that originate from natural resources, such as alginate [87], chitosan [88, 89], and hyaluronic acid [90], and that are synthetically created, such as poly (7V-isopropylacrylamide) (PNIPAAm) [91], PEO [92], PVA [93], and poly(ethylene glycol) (PEG) [94], show a poor cellular viability without modification with cell adhesive proteins or peptides, such as collagen, laminin, fibronectin, and the RGD (Arg-Gly-Asp) sequence. 

Ha, D., Lee, S., Chong, M., Lee, Y., Kim, S., Park, Y., 2006. Preparation of thermo-responsive and injectable hydrogels based on hyaluronic acid and poly(A-isopropylacrylamide) and their drug release behaviors. Macromolecular Research 14, 87—93. 

Grafts of poly(NIPAAm) have also been used to impart temperature responsive behavior to natural biomaterials for drug delivery, converting them into physically crosslinking hydrogels above the LCST of the poly(NIPAAm) portions. For example, poly(NIPAAm) grafted onto hyaluronic acid formed a gel upon injection which had a 12-hour burst release of riboflavin followed by sustained release (Ha et al. 2006). Similarly, chitosan with grafted poly(NIPAAm) was shown to release 5-fluorouracil at a controlled rate (J.W. Bae et al. 2006). 

Ekaputra, A.K., Prestwich, G.D., Cool, S.M., and Hutmacher, D.W. (2011) The three-dimensional vascularization of growth factor-releasing hybrid scaffold of poly (epsilon-caprolactone)/collagen fibers and hyaluronic acid hydrogel Biomaterials, 32 (32), 8108-8117. 

Palumbo FS, Volpe Bavuso A, Cusimano MG, Pitarresi G, Giammona G, SchiUaci D. A poly-carboxylic/amino functionalized hyaluronic acid derivative for the production of pH sensible hydrogels in the prevention of bacterial adhesion on biomedical surfaces. Int J Pharm. 2015 478 70-7. 

Hyaluronic acid naturally occurs in the connective tissues of most vertebrate animals and can be isolated from such scrap material as rooster combs. Medically, hyaluronic acid has been used in the treatment of arthritis and in eye surgery. In both cases, the poly (saccharide) achieves its special functions because it produces highly viscous solutions. Hyaluronic acid has also been used as a polymeric matrix in controlled release applications, where it behaves, at least partially, as a hydrogel. ... 

Many naturally occurring polymers, such as collagen, fibrinogen, hyaluronic acid, chitosan and heparin, have been used to make hybrid hydrogels with synthetic polymers, such as PEG, PNIPAm and PVA [31-35]. The hybridization can be performed by covalent bonding or physically interactions. For example, the IPN hydrogel composed of sodium alginate (SA) and poly(diallyldimethylammonium chloride) (PDADMAC) exhibited pH and electrical sensitive behavior [36]. 

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