A fluorescent, self-healing and pH sensitive hydrogel rapidly fabricated from HPAMAM and oxidized alginate with injectability

Multifunctional hydrogels are very interesting, although they might need complex procedures to achieve this goal. Here we report an easily fabricated injectable hydrogel, which is fluorescent, self-healing, pH-sensitive and biodegradable, from hyperbranched poly(amido amine) (HPAMAM) and oxidized alginate (OALG). The HPAMAMs are fluorescent, easy to flow, amine functionalized and biocompatible. OALGs are oxidized products of ALG, a natural polymer, with abundant aldehyde groups. When the two components were injected together, they gelled within 1 minute. The electrostatic force, hydrogen bonds and acylhydrazone bonds are the bases of the HPAMAM/OALG hydrogel. All of them are dynamic in nature. Therefore, this kind of hydrogels is naturally able to heal themselves, sensitive to the variation of pH, and biodegrade after finishing their task. The HPAMAM/OALG hydrogels are of suitable strength and porous structure, which make them good candidates in biomedical applications, from tissue engineering to sustained drug delivery.