Stimuli-responsive hydrogels for cancer immunotherapy

Immunotherapy plays an important role in cancer treatment by activating or suppressing the immune system. However, there are still a series of challenges to overcome regarding the delivery vehicles of immunotherapeutic agents and their effective activation at tumor sites. Meanwhile, owing to their well-hydrated environment and capability of immobilizing biological cargos, hydrogels in combination with immunotherapies provide a chance to enhance the antitumor immune response with reduced side effects. In addition, stimuli-responsiveness has been also widely applied to optimize the pharmacokinetics with an improved therapeutic outcome. In this review, we discuss the opportunities for the combination of immunotherapy and stimuli-responsive hydrogels, such as light, temperature, ultrasound and magnetically responsive hydrogels, for effective cancer treatment. Finally, we explore the potential of stimuli-responsive hydrogels as vaccine implants against cancer and Covid-19.