Preparation Technology Of Noble Metal@Polydopamine Core-shell Nanoparticles With Near-infrared Photothermal Effect

The noble metals gold and silver nano materials have unique surface plasmon resonance?SPR?absorption property and biocompatibility,these characteristics make it possess wide applications in surface plasmon optics,surface enhanced Raman spectroscopy,cell imaging and photothermal therapy and so on.However,under the near infrared laser irradiation,the morphology of noble metal gold and silver nanoparticles are easily changed?from non-spherical to quasi-spherical particles?,so that the near infrared absorption performance of noble metal gold and silver nanoparticles weakens or even disappears.Therefore,in order to realize the application of noble metal gold and silver nanoparticles in photothermal therapy and other biomedical aspects,people need to modify and coat the surface to improve its thermal stability using SiO₂,carbon containing compounds,polyethylene glycol?PEG?and so on.Among the coatings,polydopamine not only has a very unique adhesion,good biocompatibility and stability,but also can effectively enhance the surface plasmon resonance absorption property of noble metal nanoparticles.It is clear that the noble metal@polydopamine core-shell nanoparticles photothermal conversion agents are attracted much attention in recent years,with the advantages of combining two kinds of materials.In this paper,we mainly study on the controllable preparation technology of the noble metal nanoparticles and the near-infrared photothermal effect.The main research contents include:1.Controllable preparation gold pyramid@polydopamine core-shell nanoparticles with near infrared photothermal effectFast and efficient synthesis of the gold bipyramid@polydopamine nanoparticles in the ethanol system,and the synthetic gold bipyramid@polydopamine core-shell nanoparticles not only has high dispersion but relatively uniform size.We systematically study on the influence of morphology structure and the size of gold bipyramid@polydopamine core-shell nanoparticles which due to experiment parameter including the reaction process,temperature,solvent ratio,system environment and so on.Test results indicate that the product size and shell thickness can be precisely controlled by changing the reaction process,temperature,the amount of solvent ratio and controlling of raw materials.The emission wavelength of 808 nm laser is as for the light source to test the photothermal conversion performance of product samples.The result shows that the light conversion rate of the preparation sample is more than 60%,therefore the preparation sample reveals excellent photothermal effect.And gold@polydopamine nanospheres and polydopamine spheres were controllable synthesized by this synthetic route,and that the synthesized polydopamine spheres also have good thermal conversion performance.In a word,not only the synthetic route is simple and universal,but also the sample possesses considerable thermal effect.2.preparation technology gold@silver@polydopamine core-shell nanoparticles with near infrared photothermal effectSuccessfully synthesized gold@silver@polydopamine core-shell nanoparticles,achieved instable noble metal-silver coating and protection is implemented.Obtained gold@silver@polydopamine core-shell nanoparticles possess inerratic morphology and high dispersion.Kinetic parameters--temperature and time,the system environment and dopamine concentration are studied on the influence of size and morphology.The results show that the reaction process can be controlled by the system environment and temperature,the shell thickness of gold@silver@polydopamine core-shell nanoparticles can be effectively adjusted through the implementation of the amount of raw materials.And the controllable synthesis product of specific absorption wavelength is achieved.Then the light wavelength of 808 nm laser as the light source,the photothermal conversion of samples is measured.And the consequence shows that the gold@silver@polydopamine core-shell nanoparticles not only show outstanding photothermal conversion performance,but also have excellent thermal stability.And in the thermal treatment technology of biomedical research,it deserves available value.