Construction Of Novel Chemiluminescent Sensor Based On Luminol/carbon Dot System For Biochemical Analysis

The levels of bioactive molecules such as gas signal small molecules,proteins,DNA and enzymes produced by metabolic activities in the human body are closely related to some diseases in the body.Therefore,it has become a research hotspot for detection of these bioactive molecules with high sensitivity and selectivity in the field of analytical chemistry.Chemiluminescence?CL?has become one of the most effective detection technologies in the sensing field due to its high sensitivity,wide linear range,fast analysis speed and simple equipment.It has played a vital role in the development of life sciences,environmental sciences,and material sciences.In this paper,the synthesis of Au-Ag core-shell nanoparticles?Au@Ag NPs?and nitrogen-sulfur co-doped carbon dots?NS-CDs?possesses high catalytic activity,good biocompatibility and excellent optical properties;then combine them with CL sensors cleverly.A series of CL sensing platform for sensitive detection of bioactive molecules such as prostate specific antigen?PSA?,hydrogen sulfide?H₂S?and carcinoembryonic antigen?CEA?and the related biochemical analysis were achieved,which provide new ideas for the study of other biomarkers.The main innovations and research contents are shown as follows:1.In this study,a novel CL biosensing platform for detecton of prostate specific antigen?PSA?was developed based on the excellent catalytic performance of bimetallic Au-Ag core-shell nanoparticles?Au@Ag NPs?on luminol-K₃Fe?CN?₆ CL system.The construction process of the sensor is as follows:The prepared Au@Ag NPs were modified with anti-PSA-antibody?Ab-Au@Ag NPs?to specifically capture target molecules PSA.In the presence of PSA,a non-competitive immunoreaction occurred between Ab-Au@Ag NPs and PSA to form an immnunonanoprobe?PSA-Ab-Au@Ag NPs?.The results show that the CL catalytic ability of the immnunonanoprobe decreased with the PSA concentration increasing.And the quenching degree of CL signals is proportional to the logarithm of PSA concentration in the range of 0.1 pg mL^-1–100.0 ng mL^-1 with a detection limit of 0.047 pg mL^-1.In addition,the applicability of the present CL sensor was successfully applied for PSA determination in six human serum samples from Xinyang Central Hospital.The results were consistent with the hospital with the recoveries of 86.1%to 112.5%,and the relative standard deviations?RSDs?are no more than 5.9%.2.The previous studies found that the level of hydrogen sulfide?H₂S?in humans is closely related to some important diseases.So,it is of great significance for the sensitive detection of H₂S.In this work,the synthetic CL probe of Cu²⁺-g-C₃N₄ NSs possesses an excellent catalytic effect on the luminol-H₂O₂ system.Based on this phenomenon,a new CL sensor was constructed for the first time for high sensitivity and selectivity detection of H₂S.The construction process is as follows:In the presence of H₂S,the low-solubility CuS was formed between the dissociated S^2-of H₂S aqueous solution and the Cu²⁺of Cu²⁺-g-C₃N₄ NSs.The formation of CuS by Cu²⁺and S^2-decrease the catalytic ability of Cu²⁺-g-C₃N₄ NSs on the luminol-H₂O₂ system,which effectively annihilates the signal of luminol-H₂O₂-Cu²⁺-g-C₃N₄ system.Under the optimized conditions,the CL intensity decreased with the increase of H₂S concentration.The prepared CL biosensor for H₂S detection exhibits a linear range from 10.0 pM–50.0 nM with a low detection limit of 2.0 pM.Moreover,the method was successfully applied for H₂S determination in three human plasma samples from Xinyang Central Hospital.The results are agreement with the previous reports.The recoveries of standard addition range from 95.7%to 110.0%and the RSDs are less than or equal to 6.1%.3.In this work,a novel CL sensor was constructed for sensitive detection of carcinoembryonic antigen?CEA?based on nitrogen and sulfur co-doped carbon dot-hydrogen peroxide?NS-CDs-H₂O₂?system.Herein,the horseradish peroxidase?HRP?and the complementary DNA were co-immobilized onto Au@Ag NPs surface to form the functional nanoprobes?HRP-Au@Ag-cDNA?for signal amplification.In this proposal,HRP-Au@Ag-cDNA was specifically hybridized with CEA aptamer-functionalized magnetic beads to form the double-strand hybridization nanocomposites?HRP-Au@Ag-dsDNA-MB?.Upon the addition of CEA,the CEA aptamer preferred to bind with CEA instead of double-strand hybridization interaction,thus HRP-Au@Ag-dsDNA-MB was dehybridized and the HRP-Au@Ag-cDNA nanoprobe was released.The synergistic catalytic effects of HRP and Au@Ag NPs endow the nanoprobe producing a dual CL signal amplification in the NS-CDs-H₂O₂system.Under the optimized conditions,the CL intensity of the developed strategy enhanced with CEA concentration increasing in the range of 0.3 ng mL^-1–80.0 ng mL^-1 with the detection limit as low as 94 pg mL^-1.Besides,successful application of this CL sensor was achieved for the determination of CEA in five human serum samples from Xinyang Central Hospital.And the results are consistent with the Hospital.The recoveries of standard addition range from 89.4%to 114.0%with the RSDs no more than 9.2%.