Gamma-ray-responsive drug delivery systems for radiation protection

Undesirable exposures to the nuclear radiation will inevitably cause risks to human health, and may result in carcinogenesis, organ failure and cell mutations. It is a long-standing and urgent challenge to establish a new radiation therapy systems so as to timely reduce the radiation injury. Stimuli-responsive drug delivery systems are powerful and useful for disease treatment over the past two decades and has a profound interdisciplinary effect on scientific research. Compared with traditional radiation injury treatment strategies, recently, radiation stimuli-responsive drug delivery systems have been attracting growing interest due to their timely response and excellent efficacy. When the intelligent response carrier materials are irradiated by a specific dose of radiation, the polymer chain is broken, resulting in degradation so as to quickly release the therapeutic drug and timely treat the injury. Importantly, with emergence of a new strategy and mechanism of the injury treatment (for example, polymer radioprotectors via a multi-component reaction), a comprehensive review on gamma-ray responsive controlled-release drug delivery system with emphasis on advancements in recent years remains lacking. Issues regarding radiation injury, treatment mechanism, stimulus response-controlled release, and future prospects are discussed. This review focuses on the state-of-art of radiation therapy systems and introduces the gamma-ray responsive controlled-release drug delivery system. Furthermore, the application of the radiation stimuli-responsive drug delivery systems encapsulated by different organic matrix materials as composite materials is also reviewed. A general and substantial review looking at all aspects of the radiation injury from the principle of radiation damage to the specific application of controlled-release drug system would be of profound impact on this emerging, active, and pivotal field.