Functional Prussian Blue Nanoparticle For Photothermal Sterilization And Radioprotection

In recent years,bacterial infections have become a worldwide health problem.In traditional antibacterial therapy,antibiotics are widely used.However,the formation of bacterial biofilms can protect bacteria,leading to theincomplete elimination and bacterial mutations.In order to avoid abuse of antibiotics,a large number of studies have been conducted to developnew antimicrobial materials.Nanotechnology-based antimicrobial materials have attracted much attention due to their high antibacterial activity,good stability and low mammalian cytotoxicity.Photothermal therapy is a new kind of biological treatment.Because of its non-invasive,rapid recoveryand mild adverse effect,it can be used for the treatment of bacterial infections in the body.Therefore,photothermaltherapy of nanomaterials have a good application prospect for the treatment of bacterial infections.The wide application of the nuclear industry and ionizing radiation in daily life benefits people a lot.At the same time,there are also many threats to people.Operation mistakes or natural disasters can lead to leakage of radionuclides from nuclear power plants,such as the Chernobyl nuclear accident and the Fukushima nuclear accident.Radionuclidesin natural environment will be taken in human body via food chain,which will cause persistent radiation damage.Radionuclidesin huaman body will produce reactive oxygen species and make the body be in an oxidative stress state,causing irreversible damage eventually.Radiation protection nano-drugs can reduce the damage of ionizing radiation to normal tissues.The main protection mechanism is to effectively remove a variety of reactive oxygen species generated by ionizing radiationand excrete radionuclides,thereby protecting the internal environment.Therefore,it is important to study a new and highly effective radiation-protected nano-drugs for the removal of reactive oxygen species and radionuclides invivo.This thesis intends to use Prussian blue nanomaterials with multiple functions for bacterial infections and radiation protection.Specific studies are as follows:(1)Acetylcysteine-Decorated Prussian Blue Nanoparticles for Strong Photothermal Sterilization and Focal Infection TreatmentWe report a new strategy for efficient near-infrared radiation(NIR)photothermal sterilization and focal infection treatment by acetylcysteine-modified Prussian blue nanoparticles(AC-PB).Specifically,PB acts as an effective photothermal agent and AC could prevent the formation of bacteria cluster in biofilms and the bacterial adhesion on tissues to reduce the secretion of mucus and improve the efficacy.AC-PB shows strong synergistic photothermal sterilization ability in a concentration-dependent manner by using 980 nm NIR laser.AC-PB of ?g/mL can eliminate up to 74%of Gram-positive Staphylococcus aureus and up to 75%of Gram-negative Escherichia coli.The NIR radiation can be efficiently converted into local heat by subcutaneous injection of AC-PB to kill bacteria effectively in vivo to treat a focal infection.The antibacterial mechanism suggests that AC can destroy bacteria-based biofilms,while the photothermal effect driven by NIR may break the lipids on cellular membrane.Thus,this work may provide a promising strategy for highly effective eradication of bacteria in clinics.(2)ROS-sensitive Prussian blue nanoparticles for radioprotection along with cesium decorporationWe report a new strategy for the active oxygen-responsive nanocarriers formed by wrapping Prussian blue with polyethylene glycol phenylborate are used for radiation protection and cesium decorporation.Prussian blue has been widely studied for the adsorption of radionuclide 137Cs.At the same time,Prussian blue has the ability to scavenge reactive oxygen radicals induced by ionizing radiation.Studies have shown that Prussian blue nanoparticles can promote the formation of peroxidase,catalase and superoxide dismutase under ionizing radiation,and effectively remove free radicals to protect the body.At the same time,studies shown that Prussian blue nanoparticles have a good adsorption capacity for cesium.When the initial concentration of cesium ions is 223 ppb,the removal efficiency in blood reaches 83.6%,the removal effect of cesium in animals also reached 33.63%at 24 h(initial cesium ion concentration 300 ppb),which is equivalent to the promotion effect of traditional oral stimulating drugs at the same concentration for 48 h,thus more effectively protecting the body from the radiation damage.Therefore,this study provides a new way to clinically treat radiation protection of radioactive cesium ions in vivo.