Surface Plasmon Resonance Coupled Theranostic Nanoprobe: Enhanced Photodynamic Therapy And Fluorescence Imaging

With the rapid development of nanotechnology,nanomedicine-based cancer diagnosis and treatment methods are receiving more and more attention from researchers.Among them,nanomedicine-based photodynamic therapy is widely used due to its minimal invasiveness and ability to limit treatment to the lesion area of patients.However,since the photosensitizer exhibits a low singlet oxygen（¹O₂）quantum yield in biological tissues,the effect of photodynamic therapy is unsatisfactory.After the advent of fluorescent imaging technology,more and more researchers have applied it to general cancer detection.However,most existing near-infrared dyes exhibit poor quantum yields,which hinders their conversion to preclinical and clinical applications.Based on the surface plasmon resonance coupling effect,this paper synthesizes a novel theranostic nanoprobe,which enhances the generation of ¹O₂ and fluorescence to a certain extent.This paper summarizes the characteristics and research status of surface plasmon resonance,photodynamic therapy and fluorescence imaging through investigation.At the same time,the paper also investigates the characteristics of new nanomaterials prepared by surface plasmon resonance,and the research status of these materials in enhancing photodynamic therapy and fluorescence imaging.The latest research on the preparation of nanomaterials based on the surface plasmon resonance effect of noble metal has been mastered,which provides a basis for exploring the preparation of novel nanomaterials based on surface plasmon resonance effects.Firstly,based on the surface plasmon resonance coupling effect between AuNRs,photosensitizer Ce6 and fluorescent dye Cy5.5,a novel theranostic nanoprobe AuNR@mSiO₂-Ce6-Cy5.5 was successfully designed and synthesized.A series of optical characterization and detection were carried out,which proved that the nanoprobe realized both the enhancement of the production of¹O₂ and fluorescence.The¹O₂ generated by the nanoprobe was enhanced by 1.8 times compared with the Ce6 and the fluorescence generated by the nanoprobe was enhanced by 5.0 times compared with the Cy5.5.In this paper,the biosafety,phototherapy and fluorescence imaging functions of AuNR@mSiO₂-Ce6-Cy5.5 nanoprobe were also verified at the biological level.The experimental results show that the nanoprobe have good biocompatibility,phototherapy and fluorescence imaging effects.Secondly,in this thesis,a novel plasmonic nanoparticle Ag-Au@mSiO₂ was synthesized,and the Ag-Au core of the nanoprobe was controlled as a multi-branched nanoflower.The optical characterization results show that the surface plasmon resonance coupling effect exists between Ag-Au@mSiO₂ nanoparticles and photosensitizer Ce6.Based on the surface plasmon resonance coupling effect between Ag-Au@mSiO₂ nanoparticles and photosensitizer Ce6,a novel theranostic nanoprobe Ag-Au@mSiO₂-FA-Ce6 was successfully designed and synthesized.The optical characterization and detection of the series demonstrates that the nanoprobe achieves an enhancement of¹O₂ production and is enhanced by a factor of 2.0 compared to the Ce6.Subsequently,the biosafety and phototherapy effects of Ag-Au@mSiO₂-FA-Ce6 nanoprobe were verified at the biological level.The experimental results show that the nanoprobe have good biocompatibility and phototherapy effect.Finally,based on the Ag-Au@mSiO₂-FA-Ce6 nanoprobe,another novel integrated nanoprobe Ag-Au@mSiO₂-Ce6-Cy5.5@RBM was synthesized.Through a series of optical characterization and detection,it is proved that the nanoprobe realizes both the enhancement of ¹O₂ and fluorescence generation.In addition,since the outer layer of the nanoprobe also encapsulates the blood cell membrane of the mouse,it has homology with the biological cell platform of 4T-1 tumor cell line selected in this paper,and thus may have better biocompatibility.Subsequently,the biosafety,phototherapy and fluorescence imaging functions of Ag-Au@mSiO₂-Ce6-Cy5.5@RBM nanoprobes were verified at the biological level.The experimental results show that the nanoprobe have good biocompatibility,phototherapy and fluorescence imaging effects.Based on the surface plasmon resonance coupling effect between noble metal nanoparticles and photosensitizers and fluorescent dyes,a series of novel theranostic nanoprobes were successfully designed and synthesized,which effectively enhanced the ¹O₂ and fluorescent production of photosensitizers and fluorescent dyes.The production of these nanoprobes achieves PDT treatment and fluorescence imaging of cancer.In addition,these nanoprobes have strong absorption of near-infrared light,superior photothermal conversion efficiency,and can realize photothermal treatment of cancer.Finally,experiments have verified that nanoprobes have good biocompatibility.Therefore,these nanoprobes provide a basis for clinical integration of cancer diagnosis and treatment,and have high potential for clinical transformation applications.