Related Experiment Video
Updated: Feb 12, 2026

Free Radicals in Chemical Biology: from Chemical Behavior to Biomarker Development
Published on: April 15, 2013
Efficient Active Oxygen Free Radical Generated in Tumor Cell by Loading-(HCONH₂)·H₂O₂ Delivery Nanosystem with
Lei Xu1, Yiran Shao2, Chengkang Chang3,4
1School of Materials Science and Engineering, Shanghai Institute of Technology, Shanghai 201499, China. 156081122@mail.sit.edu.cn.
Abstract:
Tumor hypoxia is known to result in radiotherapy resistance and traditional radiotherapy using super-hard X-ray irradiation can cause considerable damage to normal tissue. Therefore, formamide peroxide (FPO) with high reactive oxygen content was employed to enhance the oxygen concentration in tumor cells and increase the radio-sensitivity of low-energy soft-X-ray. To improve stability of FPO, FPO is encapsulated into polyacrylic acid (PAA)-coated hollow mesoporous silica nanoparticles (FPO@HMSNs-PAA). On account of the pH-responsiveness of PAA, FPO@HMSNs-PAA will release more FPO in simulated acidic tumor microenvironment (pH 6.50) and subcellular endosomes (pH 5.0) than in simulated normal tissue media (pH 7.40). When exposed to soft-X-ray irradiation, the released FPO decomposes into oxygen and the generated oxygen further formed many reactive oxygen species (ROS), leading to significant tumor cell death. The ROS-mediated cytotoxicity of FPO@HMSNs-PAA was confirmed by ROS-induced green fluorescence in tumor cells. The presented FPO delivery system with soft-X-ray irradiation paves a way for developing the next opportunities of radiotherapy toward efficient tumor prognosis.
Related Concept Videos
X-ray Crystallography
Diffraction
Diffraction is the change in the direction of travel experienced by an electromagnetic wave when it encounters a physical barrier whose dimensions are comparable to those of the wavelength of the light. X-rays are electromagnetic radiation with wavelengths about as long as the distance between neighboring...
Radical Reactivity: Nucleophilic Radicals
Radicals
Radical Reactivity: Electrophilic Radicals
X-ray Imaging
Radical Autoxidation

