Tough and biodegradable polyurethane-curcumin composited hydrogel with antioxidant, antibacterial and antitumor properties.

The functionalization of tough and biodegradable hydrogels is an important way to broaden their applications in biomedical field. However, most of the hydrophobic functional drugs are difficult to incorporate with the hydrogels. In this work, curcumin (Cur), a hydrophobic functional drug, was chosen to composite with polyurethane (PU) to obtain PU-Cur hydrogels by a direct and simple in-situ copolymerization. The incorporation of curcumin in PU hydrogel increases the crosslink but reduces the hydrophilicity and degradation rate of PU-Cur hydrogels. Thus, it can increase the mechanical strength to a maximum of 6.4±0.8 MPa and initial modulus to a maximum of 3.0±0.4 MPa. More importantly, curcumin incorporated in PU networks is not deactivated. The degradation products of PU-Curs at relatively low concentrations (2.5 mg/mL) can scavenge free radicals very efficiently (maximum over 90%), which exhibits strong antioxidant properties to improve wound healing. Moreover, based on the photochemical activity of curcumin, notable inhibition effects of the degradation products of PU-Curs against bacteria (maximum over 80%) and cancer cells are demonstrated with blue light treatment as a photodynamic therapy (PDT). Therefore, the beneficial effects of curcumin are retained in PU-Cur hydrogels, suggesting potential use as wound dressings or tumor isolation membranes. This work proposes a promising strategy to combine hydrophobic functional drugs with hydrophilic hydrogels for applications in a wide range of biomaterials.