Sustained reactive oxygen species generation from percarbamide nanomedicine via a mechanism of X-Ray-initiated free radical chain reactions

Free radicals are toxic agents known to induce cellular oxidative damage, and reactive oxygen species plays a key role in cancer therapy. Herein, we develop an efficient delivery nanomedicine for controlled free radical generation by loading innocuous percarbamide in chitosan-coated hollow mesoporous silica nanoparticles (PCA@HMSNs-CTS). Reactive oxygen species was generated continuously and kept at a high level during the sustained release process of hydrogen peroxide from PCA@HMSNs-CTS. The evidences for mechanism revealed an autocatalytic free radical chain reactions initiated by a short time soft-X-Ray. The reactive oxygen species intensity in solutions after initiation is 5.8-fold higher than that without soft-X-Ray initiation following with the decomposition of hyperoxides and generation of oxygen. PCA@HMSNs-CTS exhibit a pH-responsive reactive oxygen species release, and the reactive oxygen species exhibit a significant high level in cancer cells which efficiently decrease the cell viability. This work explores the radical generation strategy of percarbamide nanomedicine and is expected to present a new avenue to efficient nanomedicine for cancer therapy.