| Since the enzyme cascade mechanism connects two or more catalytic reactions in series to improve catalytic performance and efficiency,and amplify the reaction signal,it is regarded as a promising amplifying method and has attracted widespread attention.And this signal amplification strategy can amplify the signal by dozens of orders of magnitude in a short time.Immobilization using nanomaterials as carriers can provide a comfortable microspace for natural enzymes and maintain their activity under extreme conditions,resulting in better reusability,reactivity,selectivity,substrate specificity,and stability of the cascade reaction.In this paper,an efficient and ordered multi-enzyme cascade platform was constructed based on the immobilized natural enzymes of different nanomaterials,and the rapid and sensitive detection of multiple target objects was realized by combining the analysis and detection methods of visual colorimetry and ultraviolet absorption spectroscopy.The main research contents are as follows:1.A flexible enzyme cascade sensing platform based on G-quadruplex nanofiber bio-hydrogels for colorimetric detection of glucose and xanthineThis paper proposes a new multi-objective colorimetric sensing strategy by immobilizing natural enzymes into the G-quadruplex biohydrogel doped with hemin,successfully constructing a new flexible and efficient enzyme cascade sensor(FECS)platform.Among them,the biological hydrogel not only participates in the cascade reaction as a functional hydrogel,but also acts as a nanocarrier to immobilize natural enzymes,thereby providing it with a mild microenvironment.At the same time,due to the unique characteristics of hydrogels,the FECS platform has the advantages of biocompatibility,printability and flexibility.In this article,by separately immobilizing xanthine oxidase and glucose oxidase into biological hydrogels,the FECS platform realizes low-concentration detection of xanthine and glucose.2.High-efficiency nanoenzymes based on MOFs encapsulated hemin are used in enzyme cascade platform for the detection of glucoseIn this paper,a novel nano-enzyme hemin-ZIF-8 with excellent peroxidase-like activity was synthesized by doping hemin in the synthesis process of ZIF-8,and a high-performance enzyme cascade biological platform GOX/hemin-ZIF-8 for biosensor was developed by combining nano-enzyme and natural enzyme GOX.Among them,the synergistic catalysis of hemin and ZIF-8 in hemin-ZIF-8 nano enzyme makes the nano enzyme have high peroxidase-like activity.Furthermore,the porous structure of the metal-organic framework also provides a good condition for the immobilization of natural enzymes.Therefore,the high efficiency nanoenzyme cascade platform combined the advantages of both natural enzyme and nanoenzyme,with excellent selectivity and stability,and successfully realized the detection of glucose as low as 7.15 ?M.3.High-efficiency multi-enzyme cascade platform based on cruciform petal-shaped ZIF-8immobilized enzyme for the detection of organic phosphorus in vegetablesZIF-8 nanocomposite in the shape of cross flower has larger mesopore size and higher protein loading capacity,which provides a good reaction site for immobilization of natural enzymes and construction of enzym-based biosensors.In this study,through the method of one-step co-precipitation,acetylcholinesterase(ACh E),choline oxidase(CHO)and horseradish peroxidase(HRP)were simultaneously immobilized in the mesoporous structure of ZIF-8,so as to construct a multi-enzyme cascade detection platform.The sensitive detection of organophosphorus pesticide residues was realized by enzyme inhibition method,and the detection limit of acephate was as low as 0.23 ?M.In addition,the high efficiency multi-enzyme cascade platform has excellent stability and specificity,which provides a rapid and sensitive method for the detection of organophosphorus residues in actual samples. |
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