From:  Functional hydrogel wound dressings for wound healing and localized drug delivery: materials design, mechanisms, and biomedical applications

 Comparison of major responsive hydrogel types for wound dressing and localized drug delivery.

Hydrogel typeTriggerTypical release behaviorWound-care relevanceLimitation
pH responsive hydrogelsAcidic/basic wound pHpH triggered swelling, degradation, or bond cleavageInfection and chronic wound microenvironmentsVariable wound pH may affect predictability
Temperature responsive hydrogelsLocal temperature changeSol–gel transition or thermally controlled diffusionInjectable or in situ forming dressingsLimited response range near physiological temperature
Glucose responsive hydrogelsElevated glucose/glucose oxidase reactionGlucose-dependent release and antibacterial activityDiabetic wound healingRequires careful control of oxidative by-products
ROS responsive hydrogelsExcess reactive oxygen speciesOxidative degradation and drug releaseInflamed and infected woundsOver-response may weaken the network
Enzyme-responsive hydrogelsBacterial enzymes or matrix metalloproteinasesEnzyme mediated degradation or cargo releaseInfection responsive and chronic wound therapyEnzyme levels vary between wounds
Multi stimuli responsive hydrogelsCombined pH, glucose, ROS, enzymes, or temperatureMore selective and adaptive releaseComplex chronic wound microenvironmentsMore complex formulation and validation