Super-resolution Localization Imaging Methods And Applications Based On Aggregation-induced Emission Probes

Duo to the limitation of optical diffraction limit,it is difficult for optical microscope to explore the microscopic world within 200 nm.The emergence of super-resolution imaging has maken it possible for optical microscope to bypass the limit of the optical diffraction limit,so that optical microscope can also have ultra-high resolution comparable to electron microscope.Among many super-resolution imaging technologies,super-resolution imaging based on single-molecule(usually referred to as super-resolution localization imaging)uses the fluorescent scintillation behavior of fluorescent probes to achieve single-molecule-level localization of nanostructures.At present,the commonly used super-resolution localization imaging probes mainly include fluorescent proteins and organic fluorescent dyes,but they have some problems,such as poor photobleaching resistance,difficulty in fluorescent labeling of samples,need additional buffers for deoxygenation and auxiliary fluorescence scintillation,and insufficient imaging ability for dynamic process,these problems limit the applications of super-resolution localization imaging.In view of this,this paper has developed some new methods of aggregation-induced emission(AIE)probes for superresolution localization imaging.The electrostatic interaction and specific binding between the aggregation-induced emission probes and the sample can be used to super-resolution localization imaging directly.The main research contents of this article are as follows:(1)Based on super-resolution localization imaging of co-stained spiropyran(SP)with AIE effect and block copolymer PSt-b-PEO self-assembled nanomicelles,the effects of external conditions such as excitation light,quenching light and exposure time of s CMOS on the super-resolution localization imaging resolution were studied.Under the optimized imaging conditions,the spatial resolution of the SP probe was increased from nearly 50.0nm to 25.0 nm,and the spatial resolution reached 34.4 nm under the condition of a time resolution of 3 s.The experimental conditions were optimized for the development of subsequent work.(2)A super-resolution localization imaging method that is universally applicable to nanostructures with charge properties was proposed.The fluorescent switch generated by the reversible electrostatic interaction between the ionic AIE probes and the sample,without the need to perform fluorescent labeling of the test sample in advance and additional auxiliary buffer solution,can realize the random lighting of the sample surface fluorescence for super-resolution localization imaging.Using a series of ionic AIE probes,superresolution localization imaging of silk protein nanofibers,silver nanowires,bacterial cellulose and hen egg white lysozyme fibrils was achieved,with a resolution of up to 30.0nm.(3)A super-resolution localization imaging method suitable for amyloid fibrils was proposed.The fluorescent switch generated by the reversible specific binding between the linear AIE probes and the ?-amyloid fibrils could realize the random lighting the ?-amyloid fibrils to perform super-resolution localization imaging.By comparing the super-resolution localization imaging between the two linear AIE probes PD-BZ-OH and PD-NA-OH and the commercial probe Thioflavin T,it was found that PD-BZ-OH has the best superresolution imaging effect on ?-amyloid fibrils,and the resolution can reach within 35.0 nm.(4)the AIE probe PD-BZ-OH with the best imaging effect was selected to complete the in situ dynamic super-resolution localization imaging of amyloid fibrillation from hen egg white lysozyme for more than two hours,to further study the super-resolution localization imaging ability of AIE probe for dynamic process.The imaging method based on specific binding of AIE probe can directly perform super-resolution localization imaging of amyloid fibrils formed in the solution without advance fluorescent labeling,with a resolution of 35.5 nm,which provides a convenient,long-time and nano-level resolution in situ dynamic imaging method for the pathological research of Alzheimer's disease and other neurological diseases.