Electrochemical And Electrogenerated Chemiluminescence Aptamer Sensors Of 5-hydroxytryptamine And Dopamine

Neurotransmitters（NT）are chemicals that transmit information between neurons or between neurons and effector cells,such as muscle cells,gland cells,etc.Neurotransmitters are involved in neurotransmission between neurons,affecting psychological and physiological functions.They play crucial roles in brain development,learning,memory,mood,sleep,consciousness,blood pressure,and heart rate.5-hydroxytryptamine（5-HT）and dopamine（DA）are important monoamine neurotransmitters involved in the human nerve,blood and immune system.Increased or decreased 5-HT and DA concentrations are associated with diseases such as depression,Parkinson’s disease,and the gastrointestinal tract.It is important to establish simple,highly sensitive and highly selective determination methods of 5-HT and DA content.The development of electrochemical aptamer sensing assays to detect neurotransmitters has gained attention in recent years.It is a research direction of analytical chemistry to further develop high sensitivity and selectivity detection of neurotransmitters and expand its application scope.This paper with"Electrochemical and electrogenerated chemiluminescence aptamer sensors of 5-hydroxytryptamine and dopamine",with 5-HT and DA as analyte,aptamer as molecular recognition material,combined with electrochemical and electrogenerated chemiluminescence analysis,prepared two new electrochemical and electrochemiluminescence aptamer sensors,established the electrochemical and electrogenerated chemiluminescence analysis methods.The main research contents are as follows:1.A label-free electrochemical aptasensor was fabricated for the determination of5-hydroxytryptamine by the employment of specific binding between 5-HT and aptamer and directly electrochemical measurement of 5-HT oxidation.The comparison between two aptasensors and two strategies was studied.An electrochemical aptasensor fabricated using 57-mer aptamer was facilely used to determine 5-HT in the range from 1μmol/L to 100μmol/L with detection limit of 0.3μmol/L via one-step recognition and detection.This work demonstrates that electrochemical method combing aptamer recognition and 5-HT oxidation provides an alternative and promising method for the determination of 5-HT with good selectivity and simplicity.2.Dopamine is the most abundant catecholamine neurotransmitter in the brain.As a neurotransmitter,dopamine regulates various physiological functions of the central nervous system.It is very significant to detect DA with high sensitivity and good selectivity.Here,a sensitive and selective electrogenerated chemiluminescence（ECL）aptasensing method was developed for the determination of DA based on target-induced conformational displacement.An anti-DA specific aptamer spliting into two ss-DNA（S1 and S2）was used as molecular recognition elements while an ss-DNA labeled with ferrocene（Fc-CS1,complementary to S1）was used as quenching probe.An ECL platform was prepared by dropping the mixture of Nafion,gold nanoparticles（Au NPs）and Ru（bpy）₃²⁺onto glassy carbon electrode（GCE）.After hybridization of S1 and Fc-CS1,ds-DNA（S1-CS1-Fc）was self-assembled onto the ECL platform to form an ECL aptasensing platform.In the presence of dopamine and S2,a S1-S2-DA complex was formed and then Fc-CS1 was released from the electrode surface,resulting in an increase of ECL intensity.DA can be sensitively detected in the range of 1.0×10^-9 mol/L to 5×10^-8 mol/L with a lower detection limit of 0.32 nmol/L.This is first report of ECL aptasensing method for the determination of DA based on target-induced conformational displacement.The proposed ECL aptasensing method,exploiting both the aptamer recognition and ECL detection,allows direct detection of DA in diluted serum samples with high sensitivity and good selectivity,which may be further applicable in other neurochemicals assay and biomedical research.