Injectable self-healing cellulose hydrogel based on host-guest interactions and acylhydrazone bonds for sustained cancer therapy

Tumor local chemotherapy employing injectable hydrogel reservoirs is a promising platform to achieve precise drug administration. However, balanced injectability, pH-responsiveness and long-term hydrolysis resistance of self-healing hydrogels remain appealing challenges. Herein, a modular preassembly strategy combining host-guest interactions with dynamic acylhydrazone bonds, was exploited to fabricate injectable cellulose-based hydrogels (CAAs) dressed with self-healing properties, pH-responsiveness and hydrolytic degradation resistance. Attributed to the host-guest interaction between β-cyclodextrin (CD) and 1-adamantane (AD), the hydrogels exhibited injectability, self-healing properties (healing efficiency of 97.5%) and rapid recovery (< 10 min) without external stimuli in physiological environment. Moreover, the hydrogels equipped with dynamic acylhydrazone linkages underwent slow hydrolytic degradation (> 30 days) and pH-responsive behavior, endowing the hydrogels with precise spatiotemporal drug release administration. The in vivo application of CAA as a carrier was studied using doxorubicin (DOX) model drug, and the results shows that using CAA as DOX carrier not only greatly enhances the anti-tumor efficacy of DOX, but also reduced the side effects of DOX. With the preassemble approach combining host-guest interactions with dynamic acylhydrazone bonds, this work demonstrated a multi-functional self-healing hydrogel as drug carrier developed by using natural polysaccharides, which offers a new avenue for the high-value utilization of biomass. The strategy demonstrated in the present work may also supply a pathway for the preparation and regulation of hydrogels as intelligent biomedicine materials.