<scp>pH</scp>‐Driven Multilevel Controllable Injectable Hydrogel for Wound Sealing

ABSTRACT While various biomedical sealants exist, many suffer from several drawbacks. For example, hydrogels with superior sealing properties often exhibit limitations such as conflict‐free, individual, and flexible control over injectability and gel physical properties, as well as limitations regarding applications in diverse sealing scenarios. This article presents PL/OHA, a pH‐driven injectable hydrogel sealant designed for wound sealing. PL/OHA employs dynamic bonds, including Schiff base and hydrogen bonds, to produce a biodegradable and biocompatible hydrogel sealant. By individually adjusting the pH value and solid content, the gelation time, mechanical properties, and adhesion strength of PL/OHA can be flexibly controlled to meet different requirements in various wound‐sealing contexts. Experiments prove that the injection time of the hydrogel can be flexibly controlled, from several seconds to tens of minutes, by changing the pH value. It also exhibits adjustable mechanical properties. When the solid content of the hydrogel is increased from 24% to 36%, the tensile strength increases from 10.12 to 25.12 kPa, and the compressive strength increases from 97.50 to 516.61 kPa. PL/OHA also exhibits remarkable antibacterial activity, wound healing promotion capacity, and excellent biocompatibility. These properties make it a promising candidate for future clinical applications in wound sealing.