Preparation Of (Plasmonic Metal)/(Tin Dioxide) Core/Shell Nanostructures For Their Photothermal Properties

Noble metal nanocrystals have great potential applications in catalysis,solar energy harvesting,sensing,and biological science.In particular,Au nanocrystals are much more attractive owing to their unique localized surface plasmon resonance?LSPR?.Au nanocrystals exhibit strong photothermal effects under LSPR and the temperature on the surface of Au nanocrystals can even reach up to 500?.These properties makes them an important role in biophotothermal therapy.Surfactants?such as cetyltrimethylammonium bromide?are often used in the preparation of Au nanocrystals to guide crystal growth and prevent particle aggregation.These surfactants are always biologically toxic to cells,which largely limits the application of gold nanocrystals in biology.However,in the process of cleaning the exposed Au nanocrystals,the agglomeration will affect the cell phagocytosis and the subsequent photothermal therapy?PTT?effect.Fortunately,The core/shell nanostructures can protect the agglomeration during particle cleaning.The oxide semiconductor SnO₂ is an ideal candidate for the shell of the core/shell nanostructure due to its good biocompatibility and no toxicity to cells.Therefore,the preparation of Au/SnO₂core/shell nanostructures with high photothermal conversion efficiency,the study of their photothermal effects and the corresponding PTT effects are of great significance for the development of this field.We urgently need to develop?plasmonic metal core?/?tin dioxide shell?nanostructures with good photothermal properties as photothermal materials for PTT.In this paper,the Au/SnO₂ core/shell nanostructures with surface plasmon effect were synthesized by wet chemical method,and their photothermal effects and PTT effects were evaluated.The specific work content is as follows:1.Synthesis of AuNRs nanoparticles using an classical seed growth method.We can achieve a longitudinal resonance peak of AuNRs ranging from 580 to 1100 nm.By using SnCl₄ to hydrolyze into SnO₂ in an alkaline environment,we realized the synthesis of AuNR/SnO₂ core-shell nanostructures by adjusting the pH and temperature of the solution.In addition,we also explored the AuNRs coated SnO₂ shell with different longitudinal and multi-step coating method for hell and tested the photothermal performance.The tunability of the resonant peaks of AuNR/SnO₂ particles in visible to near infrared is realized.Meanwhile,AuNR/SnO₂ with resonance absorption peak at 808 nm was used as an example to study its effects on PTT in biological cells.2.By using a variety of monometallic or bimetallic nanocrystals as seeds,such as monometallic Au,Pt,Pd and bimetallic Au/Pt,Au/Pd,the?bimetallic core?/?tin oxide shell?nanostructures were synthesized.In the process of synthesis,we explored the morphological evolution and regulation bimetallic core/tin oxide shell nanostructure.We also evaluated the photothermal effect of all the metal/SnO₂ nanostructures.The results showed that they all show a high photothermal efficiency and good photothermal effects.