Synthesis And Application Of Aptamer Functionalized Persistent Luminescence Nanoprobe

Optical imaging plays a critical role in obtaining a molecular-level understanding of the biomolecular state and function.Due to its non-invasive operation,real-time response and high sensitivity,optical imaging has emerged in extensive applications in biomarker detection,diagnosis and therapeutic guidance.Generally,optical probes need a targeting unit to achieve high specific imaging in vivo.Owing to their specific recognition,aptamers have been developed into the targeting units of optical probes and are widely applied in bioimaging.However,conventional luminescent units are susceptible to suffering from background interference from biological tissues,which decreases the sensitivity and signal-to-noise ratio of the optical probes,making them difficult to realize high-resolution bioimaging.Persistent luminescence nanomaterials that their defects are used to store energy can continue to emit luminescence after ceasing excitation.Relying on their long-lasting luminescence,persistent luminescence nanomaterials have unique advantages in avoiding the interference of background fluorescence from biological tissues and improving imaging sensitivity,being considered ideal luminescent units for bioimaging probes.Therefore,combined with the specific recognition of aptamers and the background-free of persistent luminescence nanomaterials,aptamer-functionalized persistent luminescence nanomaterials are expected to realize high-specificity and high-sensitivity bioimaging.In this paper,based on the hydrophobic interaction between the ferrocene group of artificial DNA aptamer and oleic acid ligands on the surface of persistent luminescence nanoparticles,persistent luminescence nanoprobes functionalized by artificial ferrocene-nucleotide modified DNA aptamers were constructed and applied in imaging of lung cancer cells A549.And the specific research contents are as follows:（1）The effect of the introduction of artificial ferrocene-nucleotides on the properties of DNA aptamers Apt16 was investigated.The DNA aptamers modified by three artificial ferrocene-nucleotides（Fe₃-Apt16）were synthesized and their properties including stability,cellular internalization,specificity and affinity were studied.Then,these studies showed that Fe₃-Apt16 had higher serum stability than Apt16,and could selectively enter A549 cells.Subsequently,flow cytometry indicated that the dissociation constant of Fe₃-Apt16 was 36.8±10.1 nM,but that of Apt16 was 50.4±7.6 nM,showing the improved specific recognition of Fe₃-Apt16.（2）The imaging performance of persistent luminescence nanoprobes functionalized by artificial ferrocene-nucleotide modified DNA aptamers was further studied in A549cells.Firstly,persistent luminescence nanoparticles Zn_1.4Ga_1.2Ge_0.4O₄:0.5%Cr（ZGGO:Cr）were directly synthesized.Furthermore,Fe₃-Apt16@ZGGO:Cr nanoprobes were constructed by phase transfer.It was found that Fe₃-Apt16@ZGGO:Cr nanoprobes showed regular morphology,good dispersion,long afterglow lifetime and great biocompatibility.Besides,high-specificity and high-sensitivity imaging of Fe₃-Apt16@ZGGO:Cr nanoprobes in A549 cells has been achieved by confocal imaging.