Preparation And Optical Properties Of Terpyridyl Consisted Two-photon Absorbing Nanocomposites

In recent years,cancer,a killer that threatens human health,has gradually received people's special attention.People's fear of cancer is also gradually increasing.At present,the main treatments for cancer are surgery,chemotherapy and radiotherapy,but it is accompanied by pioneering wounds and high toxic side effects.Opening up new cancer treatment methods to improve the cure rate and quality of life of patients is a scientific problem that needs to be solved urgently in this field.Recently,phototherapy(including photothermotherapy and photodynamic therapy)has attracted the attention of scientists.Common photoreactive agents are single-photon absorption materials with strong absorption in the near-infrared band.Compared with single photons,two-photon technology has more Strong tissue penetration,high spatial resolution,and minimal light damage to tissues and cells,and therefore has a better application value in the field of cancer phototherapy.The effective two-photon absorption photoreagents need to have a large two-photon absorption cross section(?).In this thesis,the two-photon absorption terpene pyridine derivative(L)was bonded to the chalcogenide using the bridging effect of-NCS.On the surface,an organic-inorganic nanocomposite material was obtained,and the influence of interfacial coordination on the two-photon absorption properties of the material was further studied,and the application of the material in two-photon phototherapy was explored.The specific research content is as follows:(1)Preparation,Characterization and Optical Properties of L-ZnS NanocompositeA functional ligand L was designed to synthesize L-ZnS nanocomposite two-photon absorbers.Raman spectroscopy(Raman)and X-ray photoelectron spectroscopy(XPS)verified the bridging coordination of-NCS at the interface.The composite process caused changes in the morphology and single/two-photon optical properties of the material:the rod-like structure,and the composite material was a sheet structure;the red-shifited UV-Vis absorption peak was 59 nm and the single-photon fluorescence emission red-shifted after compounding.At 144 nm,the fluorescence quantum yield(?)decreased by 20%,the fluorescence lifetime increased by 1.41 ns,and the two-photon absorption cross section(8)increased by 42 times.(2)Application of L-ZnS Nanocomposite in PhototherapyThe aqueous dispersion of L-ZnS nanocomposite has obvious two-photon photothermal conversion effect,and the temperature rises to 50 ? in 4 min with 860 nm laser irradiation.The composite material can target the endoplasmic reticulum(ER)through the cell membrane of HeLa cells through the selective recognition of copper ions.Under the irradiation of 820 nm laser,HeLa cells start to apoptotic from the cytoplasm and release active oxygen free radicals.(ROS):After 10 min of laser irradiation,the cell death rate was 53%,achieving a combination of two-photon photothermal and photodynamic therapy.(3)Preparation,Characterization and Optical Properties of L-CdS NanocompositeBased on the principle of energy level matching,the L-CdS nanocomposite hollow spherical structure was prepared by synthesizing the L-aggregate of spherical structure and CdS interface with-NCS bridging coordination.The UV-Vis absorption peak of the composites is 55 nm red shift compared with L,single-photon fluorescence emission is red-shifted 137 nm,fluorescence quantum yield(?)is reduced by 26%,fluorescence lifetime is extended by 0.37 ns,and two-photon fluorescence emission is red-shifted by 45 In nm,the two-photon absorption cross section(?)increases by 6 times.The material has potential applications in optical limiting and electroluminescence with a clipping threshold of 490 mW.(4)Preparation and Optical Properties of nano gold modified by Zn(SCN)2 coordination compoundBased on the principle of energy level matching,the L-Zn(SCN)2 interface complexes prepared as described above utilize their terminal sulfur and gold nanoparticles to prepare L-Zn(SCN)2-Au nanocomposites,and are searched by ultraviolet-visible absorption spectroscopy.The UV-Vis absorbance peak of the composite shows a new peak at 530 nm compared with the complex L-Zn(NCS)2,single-photon fluorescence emission redshifts 20 nm,fluorescence lifetime shortens 0.17 ns,and two-photon absorption cross section(?)Increase 30 times.The material was heated to 50 ? for 4 min at 860 nm laser irradiation.Under 860 nm laser irradiation,HeLa cells began to apoptosis from the cytoplasm to achieve two-photon photothermotherapy.