Research And Application Of Thermal Responsive Temperature Probe/Optical Storage Based On Core-satellite Structure Gold Nanoparticles

In recent years,with the development of nanotechnology,noble metal nanoparticles have been used in biological detection,drug delivery and photothermal therapy due to their unique optical properties and excellent photothermal effects.After decades of development,gold nanoparticles have achieved controllable morphology and size,and have the characteristics of low toxicity,diverse surface modification,good biocompatibility,etc.,which occupies an important position in the frontier research of biomedical and plasmon optical storage.In particular,gold nanoparticles have high photothermal conversion ability and are often used in photothermal therapy and photoacoustic imaging of tumors.However,the mechanism of temperature effect on tumor cell killing is still uncertain.Therefore,a temperature probe was prepared based on core-satellite structure gold nanoparticles to investigate the relationship between temperature change caused by photothermal conversion and cell killing.The potential application value of the system in the direction of plasmon optical storage is further investigated.The main research work is as follows:1.Build a temperature probe based on core-satellite structure gold nanoparticles.Firstly,13 nm satellite Au NPs and 20 nm,30 nm and 40 nm nuclear Au NPs were synthesized by seed growth method in sodium citrate system.Moreover,the self-assembled nanonuclear satellite structure is formed by connecting two Au NPs of different sizes via a diblock DNA with a Poly A tail.Then,by changing the base length of DNA complementary fragment and optimizing the experimental conditions,we successfully prepared plasmon core-satellite structure gold nanoparticles temperature probe which can indicate temperature with high accuracy in the range of 48-62℃.2.The killing effect of photothermal therapy on He La cells at different temperatures was monitored by the core satellite structure gold nanoparticle temperature probe.Firstly,short-chain sulfhydryl PEG was connected to Au@DNA@Au temperature probes for surface modification to improve the stability of nanoparticles.Afeter co-incubated with He La cells,the dark and phototoxicity of Au@DNA@Au probe to tumor cells was tested by CKK8 method.Due to the high photothermal conversion capacity of Au@DNA@Au,the temperature around the nanomaterial rises sharply under light conditions,thus showing certain phototoxicity.Au@DNA@Au showed almost no toxicity to tumor cells in dark condition,but significantly increased toxicity to tumor cells in light condition,and gradually increased toxicity with the increase of concentration and core particle size.Photothermal experiments on tumor cells in vitro showed that He La cells showed different degrees of apoptosis after irradiation with exogenous laser(635 nm,0.5 W/cm~2)for 10min.When the temperature reached 54℃,the death rate of He La cells reached half and remained above 60℃,and almost all He La cells died.This has important guiding significance for understanding the basic principle of tumor photothermal therapy.3.Construction of optical storage based on nuclear satellite structure gold nanoparticles.Based on the above Au@DNA@Au nuclear satellite structure,we assembled a plasma thermal-sensitive optical storage for core satellite structure by altering the size of Au NPs,which was connected by three kinds of DNA with 15 nm satellite and assembled with 50 nm core Au NPs.Then,we explored its responsiveness to optical signals.The structure particles of Au@DNA@Au core satellite were connected to ITO glass through Au-S bond.Under the continuous irradiation of 635 nm exogenous laser,the changes of LSPR peak position of particles were monitored in real time.The experimental results show that,with the increase of illumination time,the scattering color of particles changes from red to orange,then to yellow-green,and finally to blue-green,and the LSPR characteristic peak of particles also changes from 600 nm to 579 nm,563 nm,550 nm.In this way,it can realize the high-speed switching of 0 and 1 data to write data,and it can realize the efficient storage of2-10 order data by changing the DNA chain length.