“…The pH is one of the biological parameters usually altered in characteristic disease states, such as tumors and microbial infections (acidic pH), so it is essential to develop a pH-responsive platform based on bioresponsive materials. 132 The design of pH responsive materials should satisfy the following requirements, that is, bioresponsive materials can dynamically change their structural properties, including swelling, contraction, dissociation and degradation, in the context of a pathological environment with low pH, thereby implementing particular bioactive molecule delivery and disease treatment. 133 ZnO NPs are pH-sensitive materials that are only stable under normal physiological conditions (pH 7.4), while in acidic conditions (pH < 5.5), the nanostructures incline to dissolve rapidly and release Zn 2+ , which can be used for antiseptic and anticancer purposes.…”