The Electrochemiluminescence Sensors For Applications In Environmental And Biological Analysis Based On Carbon Nanomaterials

Carbon nanomaterials are widely used in the application of sensing analysis,diagnosis and treatment,catalytic applications and other fields due to the advantages of easy preparation,low cost and low toxicity.The carbon nanomaterials have been as the research hotspot in chemistry,physics and materials.Electrochemiluminescence?ECL?combined spectroscopy and electrochemical sensing methods perfectly,with light signals generated by electric excitation.It is a high-sensitivity analysis technology with the merits of stable signal,low background and easy operation as well.Herein,the ECL sensors for environmental heavy metal pollutants(Cu²⁺)and tumor markers?telomerase,microRNA-155?were constructed based on carbon nanomaterials,such as N doped carbon quantum dots?N-CQDs?and carbon nitride?g-C₃N₄?.The main contents of this study are as follows:?1?A simple and effective ECL sensor for Cu²⁺detection was constructed based on N-CQDs.Firstly,the functional N-CQDs synthesized by microwave-assisted method were characterized.Then,the effects of surface functionalization of N-CQDs for ECL and fluorescence intensity was investigated.The results showed that there were so much amino functional groups on the surface of N-CQDs,which provided abundant coordination sites for Cu²⁺,so that Cu²⁺could quench the ECL signal of N-CQDs effectively.Under the optimum experimental conditions,the?ECL intensity showed a good linear relationship with Cu²⁺concentration(the range of 5×10^-4-10?M)and the limit of detection was 2×10^-4?M.The sensor owned good selectivity and stability,which also can be applied to detect Cu²⁺in real samples.?2?A ratio electrochemiluminescence sensor for Cu²⁺discriminate based on N-CQDs and lunimol was designed.An universality ECL sensor based on the composite of Cu²⁺and N-CQDs(Cu²⁺/N-CQDs)to enhance the ECL intensity of luminol was proposed for the first time.Under the optimal conditions,herein,the ratio signal is in a good linear relationship with concentration of Cu²⁺in the range of 0.05-3nM,and with limit of detection is 0.02 nM.What is more,the sensor shows excellent selectivity and stability,which can be used for Cu²⁺detection in complex sample,indicating its promising application for environmental analysis in future.?3?An ECL sensor for the detection of telomerase activity was desined based on An novel self-enhanced Au@carbon quantum dots emitter and nicking endonucleases-assisted signal amplification.Au@N-CQDs was simply synthesized by in-situ reducing HAuCl₄ by the N-CQDs as mentioned above,The Au nanomaterials not only act as the carriers for N-CQDs and DNA,and promote the N-CQDs ECL response for its merit of conductor and catalyst as well,which exhibited self-enhanced performance with tens of higher ECL efficiency compared with N-CQDs;The endonuclease Nb.BbvcI which can cleave the specific site?5?-GC?TGAGG-3??in the double-stranded DNA,which can be used for signal amplification.Thus,the dual-enhanced ECL signal accurately reflected the telomerase activity with a wide linear range of 1.6×10^-10-1.6×10^-7 IU/L and the low detection limit of 5×10^-11 IU/L.In addition,the proposed biosensor can be used to evaluate telomerase activity of cell extracting and realized the limit of detection of single cell,suggesting its promising application for early clinical diagnosis.?4?The concept of washing-free electrochemiluminescence sensor with enhancement of the mimicking horseradish peroxidase activity and its application for detection of miRNA-155 was proposed.Herein,an enhanced intrinsic peroxidase-like activity of g-C₃N₄ with single stranded DNA?ssDNA?to catalyze the electrochemiluminescence intensity in the presence of luminol/H₂O₂,and the catalyze mechanism was investigated as well.A self-powered,target-triggered DNA walker to amplify the ECL signal was well designed with mild separation based on Au-Fe₃O₄.The results show that ECL signal is in a good linear relationship with concentration of target in the range of 3 to 1000 fM,and with the detection limit of 1 fM,and the sensor can recognized the target in both different cell lines and complicated systems,indicating its promising application for early clinical diagnosis.