The Synthesis And Structure-activity Relationship Of Nanoparticles For Cancer Cell Imaging And Phototherapy

In recent years,cancer has been one of the leading causes of death.With the development of science and technology,nanomaterials play a crucial role in the diagnosis and treatment of cancer.As two minimally invasive treatments,Photothermal Therapy(PTT)and Photodynamic Therapy(PDT),have broad application prospects in the diagnosis and treatment of cancer due to their high ablation efficiency,excellent spatial resolution and minimal side effects on normal tissues.However,at present,there are not many cases in which nanomaterials are applied in clinical practice,and there are mainly a series of problems such as biological compatibility,targeting and therapeutic efficiency to be improved.Therefore,through the synthesis of nano-bismuth sulfide and polymer carbon quantum dots,this paper improves the method of synthesizing precursors by surface modification,so as to improve the anticancer activity and imaging effect of nano-materials,and provide experimental and theoretical basis for the research of ultra-small particle quantum dots in biochemistry.This paper consists of three parts.The first part takes Bi₂S₃ nanometer bar as the core and uses fluorescein isothiocyanate and folate-modified human serum albumin(HSA-FITC-FA)as the shell to prepare composite nanomaterials.Due to in the physiological environment,the nanoparticles will quickly form a halo on the surface of proteins after binding to them,which will significantly reduce their targeting.In this chapter,we pass folic acid(FA)on the surface of human serum albumin(HSA)to increase the penetration efficiency of bismuth sulfide nanorbs into cancer cells by 1.4 times.Through fluorescein isothiocyanate(FITC)and imaging technology.We found that the photothermal therapeutic agents obtained in the experiment were accumulated in lysosomes,and HSA-FITC-FA showed good photothermal therapeutic effect under near-infrared laser irradiation.We further by Sodium dodecyl sulfate polyacrylamide gel electrophoresis(SDS-PAGE)can find that the achieved HAS-FITC-FA can significantly reduce serum protein in the champions league in bismuth sulfide formed on the surface of the nanorods,thus improve the targeting of nanomaterials,the strategy for the preparation of efficient light of nanomaterials provide s theoretical and experimental reference..In the second part,we adopted a high temperature synthesis,ligand exchange,and polymer modification strategy to obtain ultrafine,water-dispersed,and stable polylysine-bismuth sulfide quantum dots(PLL-Bi₂S₃ QDs).In addition to the near-infrared(NIR)absorption capacity,the superfine size and sulfur-rich surface of the obtained Bi₂S₃QDs provide a large number of photoelectrons with high reduction capacity,which can promote the rapid generation of reactive oxygen species(ROS).Therefore,under the irradiation of 808 nm near-infrared laser,the obtained bismuth sulfide can achieve excellent photothermal conversion and rapid ROS generation at the same time.PLL-Bi₂S₃ QDs has been proved to have good biocompatibility and PTT/PDT activity in vitro and in vivo,so the PLL-Bi₂S₃ QDs is expected to be an effective photoactivator for the treatment of cancer.In the third part,we used the chemical structure of?-aminolysine derivatives as the precursor to obtain highly stable Carbon dots(CDs)by hydrothermal method.Due to its good biocompatibility and simple preparation,fluorescent carbon spots have become a hotspot in biological application research.However,little is known about the luminescence mechanism of CDs.We studied the relationship between the chemical structure of precursor and the fluorescence and particle size of CDs,and explored the structure-activity relationship of CDs to understand the luminescence mechanism of CDs.And which shows that the increase of the number of functional groups in the precursor can promote the improvement of the degree of cross-linking,resulting in smaller CDs size,better fluorescence performance and stronger stability.We found that CDs prepared by lysine derivatives with the most functional groups showed high stability of luminescence and strong resistance to photobleaching,which was dependent on double excitation and double emission(DE²).Further studies showed that the obtained C-CDs had good biocompatibility and showed good labeling ability for the lysosomes of suborganelles.