Cu+-containing physically crosslinked chitosan hydrogels with shape memory

Abstract

Physically crosslinked chitosan hydrogels have better biocompatibility and possess unique functional characteristics but suffer from poor mechanical properties. In the current study, we prepared Cu+-containing physically crosslinked chitosan hydrogels by exploiting ammonia fumigation and reduction of Cu2+ by NaHSO3. The content of Cu+ in the prepared hydrogels was in a low range of 4.88–29.27 μmol/g. The mechanical strength of the CTS-Cu+/NH3 hydrogels was remarkably improved up to 0.25 MPa and the elongation at break increased with rising content of Cu+ due to the dynamic crosslinks between chitosan and Cu+. Moreover, the CTS-Cu+/NH3 hydrogels demonstrated evident shape memory after exposure to air by exploiting the different coordination number of Cu2+ and Cu+. Thus, the prepared hydrogels may have good potential applications as biomedical materials.