Distinguish The Construction Of The Recognition Type Fluorescence Sensor And The Sensing Application

Inspired by the sensing principles of smell and taste,researchers have made efforts towards developing fluorescent sensor arrays that contain a series of sensor elements to provide recognition patterns to different analytes.Usually,different fluorophores or different receptors are chosen to generate an array of sensors,and to provide cross-reactive responses to analytes.The sensor arrays can not only distinguish the structure of similar analytes,but also to mixed samples,complex samples to distinguish recognition,so as to obtain effective identification information.Traditional sensor arrays are increasingly dependent on the number of sensing units,resulting in large sample consumption,data processing complexity and the excitement of many wavelengths;scientists are committed to the development of new fluorescent sensor array,with a smaller sensor unit,the data acquisition,the simpler synthesis process and the single excitation wavelength.More recently,various single-system-based fluorescence sensors with multi-wavelength cross-reactivity and fingerprint recognition have been developed by different methods.This type of sensor uses multi-wavelength cross-reactivity instead of multi-sensor unit interaction to generate recognition patterns.In recent years,a single fluorescence sensor is also of concern,a single fluorescence sensor with fingerprint recognition ability,based on multi-wavelength interactive response sensing.The advantage of this type of fluorescence sensor is the use of multi-wavelength interaction response instead of multi-sensor unit interaction response at different emission wavelengths,for a particular analyte,the sensor has a different response,in the same emission wavelength conditions,the analyte different;the response changes are not the same.Thus,the response signals at different wavelengths can be output as a signal,and the response data at different emission wavelengths are collected and processed to produce a fingerprint identification pattern for a particular analyte.Such sensors,both with the array of recognition mode,and only a single spectral scan can complete the data acquisition,greatly simplifying the data collection process,but also reduce the sample consumption.In addition,the ability of single fluorescence sensor is much larger than that of selective sensor,and the data acquisition method is a new research hotspot than the multi-sensor unit sensor.Based on the discussion of the progress of fluorescent molecular sensors and arrays with multiple-analyte detection ability or discrimination ability,a series of fluorescence sensor and arrays with ability to recognize or discriminate biological-related species such as protein,organic acids were developed in this dissertation.In the first project as described in Chapter Two,two particular bispyrene fluorophores containing hydrophilic oligo(oxyethylene)spacer,6 and 4,were synthesized,but one is with and the other is without cholesterol unit.Their ensembles with cationic surfactant(CTAB)assemblies realize multiple fluorescence responses to different metalloproteins,including hemoglobin,myoglobin,ferritin,cytochrome c,and alcohol dehydrogenase.The combination of fluorescence variation at monomer and excimer emission of the two binary sensor ensembles enables the mini sensor array to provide a specific fingerprint pattern to each metalloprotein.Linear discriminant analysis shows that the two-ensemble-sensor-based array could well discriminate the five tested metalloproteins.The present work realizes using a mini sensor array to accomplish discrimination of complex analytes like proteins.They also display a very high sensitivity to the tested metalloproteins with detection limits in the range of picomolar concentration.In the second project(Chapter Three),bispyrene fluorophore 6 was continuously used to construct binary sensor platforms with phospholipid liposomes.The liposomes containing fluorophore 6 were prepared by thin film dispersion method,where different phospholipids were used to construct liposomes.The uses of phospholipid molecules with different head groups aim to provide different interactions with proteins so as to discriminate among proteins.The dynamic light scattering measurements show that the prepared liposomes have a very uniform particle size.The photophysical behavior of 6/liposome showed that the IM/IE value decreased gradually with the increase of the concentration of fluorophore 6,and when the concentration of fluorophore 6 reached at 0.2 mM,the IM/IE value of the liposomes no longer changed significantly.Fluorescence sensing behavior studies showed that the binary ensemble 6/DMPG has turn off responses to metalloproteins ferritin and the Cyt-c,but has no responses to non-metalloproteins.The ensemble 6/DPPC has turn off responses to metalloproteins ferritin and does not responses to other proteins.Meanwhile,the sensitivity of liposome 6/DPPC to ferritin was not significantly dependent on the contained concentration of fluorophore 6.In the third project(Chapter Four),a fluorescent enhanced rhodamine B derivative with amide and tertiary amine group was designed and prepared.The rhodamine B derivatives at 10 ?M show good stability in aqueous solutions containing 0.4%acetonitrile.Fluorescence titration experiments showed that the three kinds of trivalent metal ions Fe3+,Cr3+ and Al3+ could all enhance the fluorescence intensity of Rhodamine B derivatives,and the enhanced order was Fe3+>Cr3+>Al3+ when the concentration of metal ions was the same.Sensing studies in 1%serum have found that the probe also displays a good response to Fe3+,Cr3+ and Al3+ metal ions.Then,the fluorescence response behavior to six organic acid salts such as citrate and tartrate was investigated by using the binary system based on metal ion/rhodamine B derivative as the sensing platform.The lg(I/I0)values of the fluorescence intensity of the three binary systems at 581 nm were collected and the three fluorescence response signals were combined to obtain the characteristic fingerprints to each organic acid salt.In the fourth project(Chapter Five),a novel probe based on resonance energy transfer was designed and synthesized,where pyrene and rhodamine were used as energy donor and acceptor,respectively.The added resonance energy transfer function was designed to increase the capacity of multi-wavelength cross-reactivity.Through the investigation of the basic photophysical behavior of the probe,it is found that the probe can form obvious excimer emission in HEPES buffer,and has good fluorescence stability,which lays the foundation for energy resonance transfer to occur.The results of UV/Vis measurements indicated that the probe showed only the characteristic absorption of pyrene moiety rather than the absorption of rhodamine B moiety in DMSO and HEPES.The fluorescent probe is expected to generate the multi-wavelength cross-reactivity to different metal ions in HEPES buffer.Then,the metal ion/probe binary systems will be used to identify bio-related anions.