Synthesis Of Bi-BiOI-BSA Nanoparticles And Their Photothermal/photodynamic Properties

Nowadays,the incidence and mortality of cancer have been at a relatively high level for a long time,and the traditional methods of cancer treatment themselves have some drawbacks.The emergence of new treatment methods,such as photothermal therapy and photodynamic therapy,has given new hope to cancer treatment to some extent.The basic principle of photothermal therapy is that photothermal transformers transform light energy into heat.which causes the temperature of the tumor site to rise rapidly and kill cancer cells.In the process of photothermal therapy,in order to ensure the therapeutic effect,the temperature of the tumor tissue can only raised,but too high temperature will cause inevitable damage to the nearby normal human tissue.Therefore,this limits the development and application of photothermal therapy.Photodynamic therapy is the activation of photosensitive drugs,triggering a toxic photochemical reaction that kills tumor cells.In addition,photodynamic therapy has the advantages of low toxicity,small trauma and good selectivity.However,single photodynamic therapy also has some disadvantages.For example,long-term irradiation may lead to skin allergy and other symptoms in some patients.Secondly,single photodynamic therapy can’t completely guarantee the treatment effect of cancer.In order to avoid damage to normal tissues caused by high temperature,and skin allergy caused by long-term irradiation,as well as to ensure the therapeutic effect of the system.The photothermal and photodynamic therapy are implemented by using Bi-Bi OI heterostructure nanoparticles in this paper.Bi OI is a semiconductor material with highly anisotropic layered structure and narrow band gap width,and Bi is an excellent metal photothermal material.Bi-Bi OI-BSA nanocomposite particles with core-shell structure were formed after hydrolysis and reduction in glucose glycol solution.In order to ensure biocompatibility,the surface of the nanocomposite particles was coated with bovine serum protein（BSA）.On the one hand,part of Bi in the inner layer is irradiated by 808.0 nm laser and the holes are combined to generate heat,thus bringing photothermal properties to the system.On the other hand,the heterostructure formed by the outer layer of Bi OI and Bi reduces the band gap width of the composite,so that under the irradiation of 808.0nm laser,the inner layer of Bi absorbs energy and transfers part of electrons to the outer layer of Bi OI.Thus achieving the decomposition of hydrogen peroxide（H₂O₂）into hydroxyl radical（·OH）in the tumor microenvironment.The system is endowed with photodynamic properties.In addition,the photodynamic properties of the system is further enhanced by the heat,that generated by Bi-Bi OI-BSA nanoparticles at 808.0 nm laser irradiation.Finally,the Bi-Bi OI-BSA nanocomposite particles were successfully prepared.Meanwhile,cell experiments in vitro proved that the nanocomposite particles not only had good biocompatibility,but also had excellent killing effect on cancer cells.And its killing effect was significantly better than Bi.In summary,Bi-Bi OI-BSA nanoparticles have excellent photothermal/photodynamic properties.