Titanium-doped Metal-organic Framework For Enhanced Sonodynamic Therapy

Sonodynamic therapy(SDT)is an emerging cancer treatment method with the rapid development of nanotechnology.The sonosensitizer,which can efficiently convert ultrasonic energy into chemical energy,plays a pivotal role in the SDT effect.Metal-organic frameworks(MOFs)offer new horizons for the development of novel sonosensitizers,however,improving the sonodynamic performance of pristine MOFs remains a major challenge and wide band gap confines electron excitation.In this work,we introduce titanium into Ui O-66 to obtain titanium-doped Ui O-66 nanoparticles(UTN)and explore their electronic properties.The doping of Ti significantly reduces the band gap of pristine Ui O-66 and promotes the separation of electrons and holes.Electron spin resonance(ESR)experiments showed that the hydroxyl radical levels in UTN increased by 119.3% under ultrasound irradiation.In addition,the density functional theory(DFT)calculation results indicate that the doping of titanium increases the electron orbital overlap between the organic ligand and the metal cluster,which promotes the linker-to-metal cluster charge transfer(LMCT).Cell experiments confirmed that UTN can generate a large amount of reactive oxygen species(ROS)under ultrasound irradiation and cause cancer cell apoptosis.In vivo experiments proved that UTN has good biocompatibility and can achieve 86.1% tumor inhibition rate.UTN is a very promising sonosensitizer for cancer therapy,and it also provides a valuable reference for the design of MOF-based sonosensitizers.