Construction of an Injectable Composite Double-Network Hydrogel as a Liquid Embolic Agent.

Conventional embolists disreputably tend to recanalization arising from the low filling ratio due to their rigidity or instability. As a result, intelligent hydrogels with a tunable modulus may meaningfully improve the therapeutic efficacy. Herein, an injectable composite double-network (CDN) hydrogel with high shear responsibility was prepared as a liquid embolic agent by cross-linking poly(vinyl alcohol) (PVA) and carboxymethyl chitosan (CMC) via dynamic covalent bonding of borate ester and benzoic-imine. A two-dimensional nanosheet, i.e., layered double hydroxide (LDH), was incorporated into the network through physical interactions which led to serious reduction of yield stress for the injection of the hydrogel and the capacity for loading therapeutic agents like indocyanine green (ICG) and doxorubicin (DOX) for the functions of photothermal therapy (PTT) and chemotherapy. The CDN hydrogel could thus be transported through a thin catheter and further in situ strengthened under physiological conditions, like in blood, by secondarily cross-linking with phosphate ions for longer degradation duration and better mechanical property. These characteristics met the requirements of arterial interventional embolization, which was demonstrated by renal embolism operation on rabbits, and meanwhile favored the inhibition of subcutaneous tumor growth on an animal model. Therefore, this work makes a breakthrough in the case of largely reducing the embolism risks, thus affording a novel generation for interventional embolization.