Multifunctional dynamic hydrogels crosslinked with boronic ester and disulfide bonds reinforced with oxidized cellulose nanofibers for self-healing, motion sensing, and controlled drug release

This study presents a novel multifunctional dynamic hydrogel, cross-linked with boronic ester and disulfide bonds, and incorporating oxidized bacterial cellulose nanofibers (OBCNF). The OBCNF content was optimized to achieve a material with optimal mechanical properties. The presence of dynamic boronic ester and disulfide bonds enabled efficient self-healing behavior. Moreover, the hydrogel proved to be highly effective as a flexible sensor for monitoring motion. It demonstrated stable changes in conductivity under mechanical deformation, making it suitable for applications in wearable electronics. The hydrogel also exhibited specific degradation behavior in acidic and oxidative environments, where disulfide bonds and boronic ester linkages were selectively cleaved, leading to controlled degradation of the material. Additionally, the hydrogels were shown to be cytocompatible and enable pH-dependent release of incorporated doxorubicin (DOX), with significantly higher release rates observed at lower pH, with an increase of total amount of DOX release from ~20% to ~70% when decreasing the pH from 7.4 to 5.1. These properties make the hydrogel promising from the point of view of biomedical applications. Altogether, we introduced a dynamic hydrogel based on dual dynamic covalent bond crosslinking as promising approach for development of multifaceted smart materials.