Preparation Of Functional Nanomaterials And Their Application In Electrochemiluminescence Biosensors

In recent years,electrochemiluminescence?ECL?biosensors have been widely used in drug analysis,environmental pollutant monitoring,and human-related biomolecules detection due to their inherent advantages of low background,wide detection range,fast detection speed,and high sensitivity.In this paper,ECL biosensors with high selectivity,good stability,and high sensitivity are constructed by introducing nanomaterials with low toxicity or good catalytic performance as luminescent reagents or co-reaction accelerators,combining with immunosandwiching methods and target-induced shearing strategies.The prepared low-toxic quantum dots exhibited excellentelectrochemiluminescenceproperties;andthesynthesized nano-heterostructures have good electrocatalytic activity and biocompatibility;and the self-assembled DNA nanomaterials exhibited excellent loading capacity.All of these effectively enhanced the ECL intensity of the system,improved the detection performance of the sensor,and benefited the application of the sensor to clinical testing.In this paper,research work is carried out from the aspects as follows:Part 1 electrochemiluminescence immunosensor based on Mn doped Ag₂S quantum dots probe for laminin detectionQuantum dots?QDs?have been widely used as biological probes in recent years.However,most of the quantum dots used in the field of electrochemiluminescence have biological toxicity,which seriously hinders the application of quantum dots in biological detection.This work was firstly introduced a new type of low-toxic,water-dispersed Ag₂S:Mn QDs into the field of ECL and used it to construct ECL biosensor for laminin?LN?detection.In the preparation of the quantum dots,the doping of Mn effectively improved the optical and electrical properties of the Ag₂S QDs.In addition,bovine serum albumin?BSA?containing amino groups?-NH₂?could be easily combined with Ag₂S:Mn QDs via amide bonds,allowing multiple QDs to aggregate together to form a unit?BSA-Ag₂S:Mn bioconjugated complex?.The bioconjugated complex provided a large number of active sites to immobilize the antibody and form a probe,improving the ECL signal response of the sensor,thereby improving the detection sensitivity of the sensor.Compared with traditional luminescent reagents,Ag₂S:Mn QDs is a promising new type of ECL luminescent nanomaterial due to its low toxicity,good light stability,and easy surface functionalization.Part2Electrochemiluminescencepeptide-basedbiosensorwith hetero-nanostructuresasco-reactionacceleratorfortheultrasensitive determination of tryptaseIn this work,a biosensor using luminol as luminescence reagent,dissolved O₂ as co-reaction reagent and Au-Ag-Pt nanoheterostructures?AAPHNs?as coreaction accelerator was constructed,and successfully applied to tryptase?TPS?detection.The system used dissolved O₂ as a co-reaction reagent,which not only avoided the complicated operation of adding H₂O₂,but also avoided H₂O₂ harm to organisms.In addition,in order to increase the sensitivity of the sensor,we used self-assembled DNA nanotubes?DNANTs?as loading materials to immobilize Dox-Lu luminescent complexes to obtain higher signal“on”status.Finally,based on the target-induced cleavage strategy,TPS in this reaction system not only served as a target but also a cleavage enzyme,which could directly induce vasoactive intestinal peptide?VIP?to switch signals from“on”to“off”.Based on the above advantages,the proposed ECL biosensor exhibited excellent accuracy,selectivity and stability as well as a high detection limit,which was of great significance for protein detection.The introduction of co-reaction accelerators has injected new vitality into the application of the luminol-O₂ ECL system.Part 3 Electrochemiluminescence immunosensor with MoS₂-Ag NCs as a signal probe for cardiac troponin T detectionCompared with other methods for preparing nanoclusters,this work utilizes MoS₂nanosheets as carriers to generate Ag NCs,enabling highly efficient immobilization of Ag NCs without rigorous experimental conditions.In the ECL immunosensors constructed with MoS₂-AgNCs as probes,the relationship between the intensity of ECL and the logarithm of cTnT?the concentration ranged from 0.05 pg/mL to 160 pg/mL?showed a good linearity.The constructed ECL immunosensor has a detection limit of0.021 pg/mL and exhibits good stability and selectivity.We have designed a simple approach to improve the immobilization efficiency of Ag NCs in order to broaden the application of Ag NCs in the biosensor field.