Biocompatible, injectable and self-healable MOF-based anti-freezing eutectogels for higher encapsulation and sustained release of the anticancer drug curcumin†

Inspired by the antifreeze proteins found in the blood of Trematomus borchgrevtnki, a fish from the Antarctic Ocean, herein we developed metal organic framework (MOF) based ‘waterless’ eutectogels with impermeable nano-domains as antifreeze “soft” materials. The eutectogels were successfully developed through dissolving sodium alginate and ZIF-8, a known MOF, within deep eutectic solvents (DESs) prepared from the environmentally benign biocompatible cryoprotectants glucose and fructose as the HBDs and choline chloride as the HBA. The structural integrity of ZIF-8 and DES was preserved during the eutectogel formation and so also their properties. The eutectogels showcased notable attributes, including antifreeze properties, self-healing capabilities, injectability, adhesiveness, substantial drug loading capacity (∼75 000 and ∼71 000 fold higher curcumin than in water) and efficient sustained drug release behaviour. Moreover, the eutectogel also demonstrated antibacterial and antioxidant attributes, along with hemocompatibility evidenced by hemolysis levels below 2%. Furthermore, the eutectogel exhibited biocompatibility even at very high concentrations (50 mg mL⁻¹). Leveraging on its robust colloidal forces and an environmentally benign composition, the studied eutectogel proves its suitability not just for pharmaceutical applications but also for high-performance applications that prioritize ecological sustainability.