Cobalt Oxyhydroxide Nanoflakes Catalyzed Luminol Chemiluminescence And Its Application In The Assay Of Biomarkers

Biomarkers,mainly including proteins,nucleic acids,and some small metabolic substances,are the molecular marker of the physiological and pathological state of disease at a specific time.The abnormal expression of biomarkers in body fluids（urine,serum and tissue extract,etc.）is greatly related to the existence of some diseases.Therefore,it is of great significance to design a simple,rapid and accurate detection method for the detection of biomarkers,which is benefit for the prevention,diagnosis,treatment and prognosis of disease and improvement of patient survival rate.Chemiluminescence（CL）analysis has been widely used in various fields because of its high sensitivity,wide liner range,fast analysis and simple instrumentation.Compared with other luminescent reagents,luminol is the most attractive reagents due to its higher quantum yield and better water solubility.In recent years,the rapid development of nanotechnology provides a good opportunity for the sensitivity and practicality of luminol chemiluminescent system.In particular,the emergence of nanoenzymes has brought new opportunities for enhanced chemiluminescnece research.However,at present,most of the nanomaterials used to catalyze luminol CL are concentrated in zero-dimensional or one-dimensional materials,and there are few studies on CL of luminol catalyzed by two-dimensional nanomaterials.The composition,structure and mechanism of relevant two-dimensional nanomaterials are still unclear,and the application technology is not fully developed.This is not commensurate with the current situation that two-dimensional nanomaterials have a large surface area and have good potential in the field of catalysis.Based on this,in this contribution,we took cobalt oxyhydroxide nanosheets（CoOOH NFs）as the research object,and conducted a series of studies on the properties of its enzyme-like activity and the luminescence characteristics of luminol catalyzed by H₂O₂free.On the basis of establishing a new luminol chemiluminescent system and discussing its luminescence mechanism.It was then applied to detect biomolecules and cancer markers.The main content includes the following two aspects:1.Cobalt oxyhydroxide nanoflakes with oxidase-mimicking activity induced chemiluminescence of luminol for glutathione detectionCoOOH NFs were found to could directly induce luminol chemiluminescence under alkaline condition,and a new CoOOH-luminol chemiluminescent system was established for the detection of glutathione.CoOOH NFs were a new kind of two-dimensional materials with excellent enzyme-like activity.It could induce chemiluminescence（CL）of luminol since the oxidase-like activity of CoOOH NFs enable the dissolved oxygen to generate various radicals(?OH,O₂^?-and ¹O₂)even if without the addition of oxidants such as hydrogen peroxide.These radicals could be scavenged by glutathione（GSH）,making GSH could be detected sensitively in the range of 10 nM to 1μM with the detection limit of 6.4 nM.2.Utilizing cascade strand displacement reaction and liposome double singal amplification strategy for quantitative detection miRNA based on luminol-CoOOH chemiluminescenceIn order to broaden the application scope of this new chemiluminescent system,CoOOH-luminol system was combined with nucleic analysis to construct an analytical method for miRNA detection,which based on cascade strand displacement reaction and liposome double singal amplification strategy.Specifically,Carbon dots（CDs）rich in amino group were synthesized firstly.They could quench the light emission of the CoOOH-luminol system by scavenging free radicals.To amplify the signal,with the aid of liposome encapsulation technology,the CDs were encapsulated in the liposomes to obtain soft nanospheres.In addition,we achieved the second signal amplification through target-induced recycling amplification.To be more specifically,the recognition strand DNA attached to the liposome was combined with the blocker DNA modified on the magnetic beads（MBs）through partial hybridization to form MBs-DNA-soft nanosphere composite probe.Once the target miRNAs were introduced,soft nanospheres were released due to the stronger interaction between the recognition DNA and the target.At the same time,the DNA Fuel strands were introduced into the system.Because of its stronger binding force with the recognition DNA,the target strands were released from the recognition DNA-target double strands,and the target strands participated in the reaction again.This cascade of secondary chain displacement reactions made the target to participate in the reaction cyclically,thus,releasing more soft nanospheres and amplifying the signal.After magnetic separation,the soft nanospheres were broken by Triton,and then the CDs that would cause changes in the chemiluminescent intensity of CoOOH-luminol were released.Thereby establishing a linear relationship between the reduced chemiluminescence intensity of the system and the concentration of miRNA.The linear range was 0.1–20 nM,with the detection limit of 59 pM.In summary,the enzyme-like activity of two-dimensional nanomaterials represented by CoOOH NFs was studied in this paper,and a new chemiluminescent system of luminol catalyzed without hydrogen peroxide was established for the detection of biomolecule.In addition,the system was combined with nucleic acid analysis to detect miRNA,a disease marker.This study broadens the application scope of nanomaterials,especially two-dimensional nanomaterials in the field of chemiluminescence,and provides some new ideas for the application of nanomaterials catalyzed luminol chemiluminescence in the detection of biomarkers.