Preparation And Optical Properties Of WS₂ Quantum Dots And Their Application In Radiation Protection

Two dimensional WS₂ materials have attracted wide attention in condensed physics and materials science due to its unique geometric and electronic structures.Owing to higher special surface area and more active edge sites,ultrasmall WS₂ QDs usually show higher catalytic activities than regular nano-sized WS₂ particles.Especially,ultrasmall WS₂ QDs（<5 nm）can escape the absorption of reticuloendothelial system（RES）and could be excreted by kidney rapidly,resulting in little accumulation in organs.Based on unique physical and chemical properties,WS₂QDs have great potential for biomedicine application.In this work,we designed a class of highly efficient catalytic WS₂ QDs for radiation protection during cancer radiation therapies.The main contents and results are as follows:（1）Three kinds of WS₂ nanomaterials were synthesized using a combination method of ultrasonication and solvothermal treatment.The results show that as-prepared WS₂ QDs with size of 2.4 nm display excellent electrocatalytic properties,high fluorescent efficiency and strong ultraviolet absorption.（2）The protective effect of WS₂ QDs was investigated by detecting the change of biological indicators,such as cell survival rate,the ROS levels and nuclear DNA damage degree.Results show that the WS₂ QDs have excellent stability and strong photobleaching.Cells experiment in vitro indicate that the WS₂ QDs have low cytotoxicity and excellent protection performance.（3）The protective effect of WS₂ QDs in vivo was investigated by detecting the changes of indicators,such as hematopoietic system parameters,the levels of SOD and MDA.WS₂ QDs can significantly reduce cell apoptotsis,the damage of hematopoietic system,effectively improve the level of SOD and reduce the content of MDA through scavenging free radicals in vivo.（4）The biosafety of WS₂ QDs was explored through pharmacokinetics and toxicology studies.The WS₂ QDs were cleaned by kidney,and total excretion about80%in 24 h.The blood half-life is 1 h.Hematology,biochemistry and pathology suggest that WS₂ QDs cause no notable toxicological responses can be found in up to30 days,indicating the material has good biological safety.