Stimuli-responsive hydrogel for disease therapy

Due to various physiological barriers and clearance mechanisms that limit the bioavailability of drugs, the routine systemic administration of therapeutic drugs remains a great challenge. Therefore, it is essential to re-examine the alternative drugs administration system and find a suitable route of drugs delivery according to the specific situation. Hydrogel can serve as an effective local drugs administration system, which has adjustable physical characteristics and can protect unstable drugs from degradation. Hydrogel not only realize drugs targeting delivery, but also are widely studied and utilized in wound healing, soft tissues repairing, and tumor therapeutic based on their unique and versatile function. Among various traditional hydrogel, stimuli-responsive hydrogel can control drugs delivery and precise releasing to minimize adverse side effects and maximize therapeutic effects by endogenous stimuli (pH, glutathione, redox gradients and enzyme concentration) and exogenous stimuli (light, magnetic field and temperature). Herein, we summarize recent endeavors in the applications of hydrogel for disease therapy and how they could be manipulated for drugs targeting delivery and sustained releasing. Representative studies have been provided to support the advantages of hydrogel in targeted drugs delivery for various damaged areas. Finally, we prospect that hydrogel could be appropriately modified via various methods to achieve great impact on targeted drugs delivery.