Preparation And Characterization Of Heterostructure Nanomaterials For Tumor Photothermal Therapy/Imaging

Photothermal therapy（PTT）is a minimally invasive method for selective photothermal ablation of cancer cells without damaging the normal cells.In order to determine the exact location and size of the tumor and visualize the treatment of the tumor,it is particularly important to study a bifunctional nanomaterial that can simultaneously realize photothermotherapy and imaging.In this paper,AgI-Ag₂S heterostructures and Gd-C nanoparticles were prepared respectively.Their morphology and composition were characterized by XRD,TEM,HTEM,and so on.The optical absorption and photothermal properties of the samples were measured and photothermal efficiency of the samples was calculated.At the same time,the nuclear magnetic resonance imaging of Gd-C nanoparticles in the cervical lymph node was studied.The results are as follows:1.Ag I-Ag₂S heterostructure nanoparticles were prepared by in-situ sulfidation with AgI nanoparticles as a template and thioacetamide as a sulfur source.The synthesized AgI-Ag₂S heterostructure nanoparticles exhibit significant absorption from500 nm to 1100 nm.The Ag I-Ag₂S heterostructures has enhanced and broadened optical absorption properties in comparison to the corresponding AgI and Ag₂S nanoparticles.The maximum temperature rises of the AgI-Ag₂S heterostructure nanoparticle suspension with the mass fraction of 0.01 wt%are 26.7℃and 27.8°C under the irradiation of 808 nm and 1064 nm lasers（at the power of 420 mW）respectively.The corresponding photothermal efficiencies are determined to be 33.4%and 28.9%.For solar simulation experiments,the solar thermal efficiency of the above suspension is evaluated to be 50.6%.The AgI-Ag₂S heterostructures are promising in the applications of photothermal therapy and solar energy collection due their excellent optical absorption characteristics and photothermal conversion properties.2.The Gd-C nanoparticles were prepared using GdCl₃·6H₂O and citric acid（CA）in the presence of ethylenediamine by a one-step method.The prepared Gd-C nanoparticles have near spherical shape with size from 50 to 100 nm.It has been proved by the FTIR and XPS analysis that the germanium element has been successfully incorporated into the Gd-C nanoparticles,and the chemical structure of the Gd³⁺has no obvious change.The Gd-C nanoparticles show certain degree of absorption from 500 to 1100 nm.The aqueous suspension containing 1.0 wt%Gd-C nanoparticle exhibits a maximum temperature rise of 28.0 ^oC under the irradiation of808 nm laser（420 mW）.The corresponding photothermal efficiency is calculated to be30.0%.As an intravitreal magnetic resonance lymphography（IMRLG）contrast agent,Gd-C nanoparticles can characteristically display the cervical lymph nodes morphology and lymphatic shape effectively with a small dose.The Gd-C nanoparticles have remarkable photothermal conversion and imaging properties and therefore provide new methods and references for the diagnosis and photothermal therapy of cervical lymph node metastasis.