Synthesis and Characterization of Thermosensitive Poly(N‐Vinyl Caprolactam)‐Grafted‐Aminated Alginate Hydrogels

Abstract Thermosensitive hydrogels are characterized by the drastic and reversible change of their physical properties with temperature. Herein is presented the development of a thermosensitive poly( N ‐vinylcaprolactam)‐grafted‐aminated alginate (PNVCL‐ g ‐Alg‐NH 2 ) having a temperature‐dependent phase transition close to physiological temperature. The hybrid copolymer is formed through the combinational use of chemical and physical methods, that is, carbodiimide chemistry, and ionotrophic gelation by calcium cations. PNVCL‐ g ‐Alg‐NH 2 exhibits a phase transition at ≈35 °C, and temperature‐dependent water uptake. Copolymerization with PNVCL leads to a decrease in the water uptake of aminated alginate, while improving its thermal stability. Model protein (bovine serum albumin) release from PNVCL‐ g ‐Alg‐NH 2 scaffolds indicates a higher rate of release below the lower critical solution temperature (LCST) than that of the above, owing to the fact that PNVCL chains collapse at above the LCST and forms a more compact network. In vitro cytotoxicity and hemocompatibility analyses confirm that PNVCL‐ g ‐Alg‐NH 2 scaffolds are basically non‐cytotoxic and non‐hemolytic.