Investigation On Sandwich-type Electrochemistry Sensors For Glucose Based On Boronate Affinity

At present,diabetes has become one of the diseases to seriously threaten human health,the detection of blood glucose levels as an effective means of clinical diagnosis of diabetes is widely concerned by the scientific research workers.Boronic acid and its derivatives could be reversible with cis-diol compounds to produce five or six-membered cyclic esters,which could be used to synthesize molecular recognition receptors to selectively recognition sugars,glycoproteins,catechols and fluoride ions.The electrochemical sensor has the advantages of high sensitivity,fast analysis speed and easy to use.It has become a very popular analytical tool.Therefore,the study of electrochemical glucose sensor based on phenylboronic acid and its derivatives had a clinical blood glucose level test for diabetic patients.This paper was based on the formation of bidentate complexes of phenylboronic acid and its derivatives and glucose,and constructed two novel sandwich-type glucose electrochemical sensors.In addition,a kind of boronic acid derivative with electroactive activity could be achieved to without marking detection of sugar,and provide a new way for clinical detection of blood glucose levels.In the first chapter,the electrochemical sensing based on boronic acid and its derivatives in the detection of carbohydrate,glycoprotein,catechol,F-and other diols of the application were studied in recent years.Finally,some simple overviews was made to the theory and application of sandwich method.In the second chapter,a disposable sandwich-type electrochemical sensor for selective detection of glucose was established.The primary receptor,3-aminophenylboronic acid(mAPBA)was covalently immobilized onto the surface of screen-printed carbon electrodes through an in situ-generated diazo-reaction using cyclic voltammetry.Glucose was first captured by primary receptor,followed by captured the secondary receptor to form sandwich-type structure.The sandwich assay showed higher selectivity for glucose and exhibited a dynamic concentration range of glucose from 0.5 to 20.0 mM with a detection limit of 0.1 mM(S/N = 3).The disposable sensor demonstrated a good reproducibility with 2.2%relative standard deviation(RSD).In addition,the disposable glucose sensor was used in detection of the trace glucose in the clinical urine samples.In the third chapter,a highly sensitive and highly selective sandwich-type sensor for selective detection of glucose was established.Glucose was first captured by mAPBA,which was cross-linked on the surface of the chitosan-modified electrode,followed by glucose recapturing the secondary receptor mAPBA-CC to form a sandwich structure.The addition of ferrocenecarboxylic acid and hexaammineruthenium(?)chloride to form a cycle redox reaction,thereby amplifying the current response to achieve high sensitivity to detection of glucose.The sandwich sensor had a good affinity and selectivity for glucose and a good linear relationship was also observed in the concentrations of 0.02?1.0 mM and 0.1?15.0 mm,with a detection limit of 0.01 mM(S/N= 3).In the fourth chapter,a novel electroactive activity boronic acid derivative was synthesized and a new method for the detection of sugar without labeling was proposed.Synthesis of mAPBA-NQ compounds was by Michael Addition reaction with 1,4-naphthoquinone(NQ)and mAPBA.The interaction between mAPBA-NQ and sugar was studied by electrochemical method in solution.The mAPBA-NQ was immobilized on the surface of the reduced graphene by ?-? stacking and compounded on the surface of the electrode to construct the mAPBA-NQ/GO/GCE modified electrode.This provides a new idea for the direct sensing mode of the electrochemical sensor for sugars.