Pyroelectric Effect Of Janus BaTiO₃ Nanoparticles For Antitumor Treatment

Traditional cancer treatment methods are often accompanied by severe side effects.In recent years,new types of treatments,such as photothermal therapy,photodynamic therapy,sonodynamic therapy and chemodynamic therapy,have their own advantages,but they are often limited by the low level of environmental oxygen in the tumor and insufficient hydrogen peroxide content.The therapeutic effect needs to be improved.The pyroelectric effect refers to the phenomenon that the polarization of the material changes with the temperature and the charge is released.The macroscopic temperature change can make the two ends of the material produce voltage or current.In the process of temperature change,the holes and charges on the surface of the material will react with the surrounding liquid environment to produce reactive oxygen species(ROS),which can kill tumor cells.tBT nanoparticles were polarized under an electric field,followed by depostion of silver nanoparticles under ultraviolet illumiation.Through controlling the reaction time,polydopamine(PDA)was partially coated on the outside of the particles,and gold nanoparticles were in-situ deposited on the PDA layer to obtain t BT@PDA-Au Janus nanoparticles.Due to the asymmetric photothermal layer on the surface,t BT@PDA-Au NPs exhibited good motion capabilities,and the diffusion coefficients were 2.30 and 3.05?m~2/s,respectively.COMSOL was used to simulate the potential differences,and the surface potentials of t BT@PDA-Au nanoparticles were 0,1.02 and 1.98 V when the?T were 0,15and 30?C,respectively;The holes generated by the piezoelectric NPs could react with water,and t BT@PDA-Au/NIR had excellent·OH generation ability using methylene blue as the probe.In vitro cell experiments showed that photothermal therapy(PTT)and pyroelectric dynamic therapy(PEDT)of t BT@PDA-Au/NIR had a great killing effect on tumor cells.Based on the difference in membrane potential between tumor cells and normal cells,t BT@PDA-Au/NIR can selectively changed the membrane potential of tumor cells,thereby increasing membrane fluidity.The movement behavior and surface potential of t BT@PDA-Au/NIR can jointly promote the entry of t BT@PDA-Au nanoparticles into tumor cells.In a mouse subcutaneous tumor model,t BT@PDA-Au/NIR showed excellent penetration ability and high accumulation in the tumor site after injection into the tail vein for 24 h.After 27 days of t BT@PDA-Au/NIR treatment,the tumor growth inhibition rate reached 92.6%and caused the most significant apoptosis of tumor cells.The above experimental results had laid a good foundation for the combination of pyroelectric materials and biomedical applications.