Research On Amplifying Fluorescence Signal Based On Gold Nanoparticle Plasmon Resonance

Fluorescence detection has an important influence on biochemical sensors,biological imaging,medical diagnosis and treatment,light-emitting devices,photocatalysis and anti-counterfeiting.However,due to its low free state sensitivity and limitation sensitivity and accuracy,it combined with the extremely strong electromagnetic field on the surface of the precious metal.The sensitivity of the fluorescent substance can be effectively improved,making its application prospects broader.Based on the above development and application,this paper has done the following experimental research.(1)Based on synthetic Au nanorods(Au NRs)and near-infrared Ag₂S quantum dots(QDs),a metal-enhanced fluorescence(MEF)superstructure-based biosensor was designed and constructed for the first time to detect prostate cancer marker prostate cancer antigen 3(PCA3)gene.First,plasmonic Au nanorods(Au NRs)are used as core materials,near-infrared Ag₂S QDs are used as satellites,and precisely designed DNA is used as an intermediate layer to regulate the distance between Au NRs and QDs to prepare metal-enhanced fluorescence(MEF)satellite structure.Then,the corresponding chain length is designed for the specific detection of PCA3 at the DNA distance with the best fluorescence enhancement.The sensor has a good linear relationship in the concentration range of 5-500p M,and its detection limit is as low as 1.42 p M.Finally,the biosensor can be used for highly sensitive and selective detection of PCA3 in human serum samples,as well as for sensitive detection of PCA3 in PC-3 and LNCap cell lysates.(2)Based on the construction of two-dimensional films of Au nanobipyramid(Au NBPs) and upconversion nanoparticles(UCNPs),a two-dimensional luminescent film based on metal-enhanced fluorescence(MEF)was prepared.Firstly,UCNPs were modified by Si O₂as an interlayer to achieve the purpose of two-dimensional film luminescence enhancement.The influence of UCNPs coated with different Si O₂ thickness on the luminescence intensity of UCNPs films was studied.Secondly,the optimal thickness of Si O₂ was used to discuss the influence of the density of UCNPs@Si O₂ film on its luminescence intensity.The experiment found that when 80?L 10 m M DDT(dodecanethiol)was added and the average distance between the particles of UCNPs@Si O₂ film was 23 nm.Its luminescent intensity can be increased to about 10 times.Finally,the UCNPs@Si O₂ film is further composited with the Au NBPs film.Compared with the original UCNPs film,its near-infrared luminescent intensity can be increased by about 300 times.The luminescence-enhanced composite film with excellent performance has good self-adhesion and can be transferred to a flexible and foldable substrate,laying a certain foundation for anti-counterfeiting applications.