Sensor Array Based On Polymer-modulating Carbon Dots For The Discrimination Of Thiols

By mimicking the taste and smell of mammals,artificial arrays of cross-reactive receptors have been used in various sensing applications.Pattern recognition algorithms allow these arrays to be used to discriminate between analytes and even to predict the identity of unknown analytes.However,the development of sensor arrays for identifying various analytes in the past still has many challenges to overcome.Aiming at the problems of poor stability,low sensitivity and low accuracy of sensor arrays,this paper developed a new fluorescence sensor array integrating novel sensing strategies and sensing materials.Self-assembly was introduced to improve the stability and sensitivity of the sensor array,Carbon dots were electrostatically self-assembled with polyacrylic acid(PAA)and polyethylene glycol-polyacrylic acid(mPEG-b-PAA)to form CDs-PAA and polyionic micelles(PIC micelles)as sensing element to create carbon dots-Homopolymer sensor arrays and carbon dot-block copolymer sensor arrays for the discrimination of thiols.Two types of carbon dot-homopolymer sensor arrays(array 1 and array 2)were frabricated by varying the PAA concentration or degree of polymerization to investigate the effects of sensing medium Ag~+concentration,pH on the detection of thiols for array 1 and array 2,and the detection limit of thiols for array 1 and array 2.Array 1 and Array 2 fail to recognize thiols when sensing medium Ag~+=200μM;and When Ag~+=300,400μM,array 1 and array 2 can accurately distinguish six thiols.In the experiment of acid-base interference in sensor array detection of thiols,in pH=5and pH=9 detection systems,array 1 and array 2 lose the ability to distinguish between thiols.Under optimal conditions,the minimum detectable concentration of thiols for array 1 and array 2 is 5μM.In order to improve the discrimination sensitivity of the sensor array and the wide application range of the acid and alkali,and improve the structural stability of the sensing material,The concentration and degree of polymerization of mPEG-b-PAA were changed,and electrostatic coupling with CDs was used to prepare a series of polyionic complex(PIC)micelles with different concentrations and different degrees of polymerization to frabricated two kinds of sensor arrays(Array 3,Array 4).The concentration of Ag~+in the sensing medium,the effect of pH on the detection of thiols,and the minimum concentration of thiols detected by the sensor array were investigated.When the sensing medium Ag~+=100,200,300μM,array 3and array 4 can distinguish between six thiols;Only at Ag~+=50μM,array 3 and array 4 have no analytical ability for thiols.In pH-interference experiments,array 3and array 4 were able to discriminate between six thiols at pH=5,9.Based on the optimal results,the minimum detectable concentration of thiols for sensor arrays frabricated with PIC micelles is 1μM.