Study On The Substituent Effect-regulated Properties Of Neurotransmitter Probe And Fluorescence Analysis Application

As chemical messengers for transmitting brain information,neurotransmitters’ concentrations are important to the thinking,movement,work and other behaviors.And the pathogenesis of many diseases is usually related to the abnormity of neurotransmitter concentration.For example,the decreased neurotransmitter concentration may cause heart failure,neuromuscular disorders,Parkinson’s disease,and schizophrenia,etc;While the emotions of happiness and excitement are attributed to the increase of dopamine concentration.Therefore,it is of great significance for rapid and accurate neurotransmitters detection.In this thesis,substituent effect on the properties and responsive character of neurotransmitter probes has been systematically studied.With the introduction of substituent effect,dopamine selective probe and artificial neural network methods for multiple neurotransmitters detection have been proposed.In addition,the thermodynamics and kinetics characters of different substituent probes toward neurotransmitters have also been investigated.Through exploring the interaction mechanism between different substituent probes and neurotransmitters,excellent probes have been selected and applied to neurotransmitters analysis in biological samples.The main research contents are listed as follows:1.In this chapter,we studied the substitution mediated reactivities of resorcinol derivates toward DA and its analogues for the first time.It is found that the carboxyl substitution(3,5-dihydroxybenzoic acid,DHBA,metaposition substitution)allows rapid and ratiometric DA detection within 2minutes.In addition to substituents,the substituent position also plays critical role to the reaction,and the substitution nearby hydroxyl group inhibited the reactivity.Among these substrates,DHBA showed higher sensitivity and selectivity due to the substitution-enhanced thermodynamics and kinetics,and can be used for constructing ratiometric DA probe.The proposed DHBA probe showed high sensitivity(LOD: 0.3n M,S/N=3)and specificity,the presence of other amino acids,small molecules or metal ions had no dramatic effect on the selectivity.Moreover,the practical application of the proposed DHBA probe was verified by accurate DA analysis of PC12 cell lysate and human urea samples.In this chapter,we applied machine learning methods for neurotransmitter detection and prediction.As we known,this is the first example that combing machine learning technique and optical neurotransmitter probes.Based on above results,different substituents of resorcinol derivatives can rapidly react with catecholamine neurotransmitters,and the fluorescence spectra of the reaction products showed difference.The total content of neurotransmitters was determined by using DHBA as the probe.Using the fluorescence emission intensities at different excitation wavelengths of different molecules as the inputs,an artificial neural network with input layers and 3 output layers,was developed for the centration distribution analysis of four catecholamine neurotransmitters mixture.In addition to neurotransmitter identification,the content analysis at various total concentration can be realized.The practical application of this method was validated by the accurate neurotransmitter mixture analysis in PC12 cell lysates.