Construction And Application Of Colorimetric Sensor Based On Bimetallic Nanoenzyme

Natural enzyme are widly exists in various kinds of biological reaction due to its well enzyme catalysis performance,but the preparation conditions,storage instability,high cost disadvantage limits its application.In recent years,nano-enzyme has the advantages of simple preparation,low cost,high volume stability to abtain the attention of the researchers.It is an important research direction to simulate the performance of natural enzymes by using nano enzyme.Double metal nanomaterials because of its excellent photoelectric catalysis performance was widely used biomedical sensor optics electronics and other fields.Graphene is a kind of two dimensional nanomaterials,and has high electrical conductivity and large specific surface area,it is also widely used in various fields.The synergy of the two will give the composite nanomaterials more excellent performance.In this work,we use poly?styrene sulfonate?functionalized graphene?Gr?as basal material,by depositing three different kinds of double metal nanometer materials?Pt Cu,Pb Cu,Co Cu?on the surface functionalization of graphene to formed PSS-Gr/Pt Cu,PSS-Gr/Pb Cu,PSS-Gr/Cu Co nanocomposites respectively.The peroxidase and oxidase properties of the three composites were studied.Based on the synergistic effect between bimetals and between bimetals and graphene,these three bimetal nanocomposites showed good nanosomal enzyme activities,and based on this,several sensors were constructed to realize the selective detection of a variety of substances.The detailed studies are as follows:1.Detection of H₂O₂ and glucose based on the peroxidase-like catalytic activity of PSS-Gr/Pt Cu,PSS-Gr/Pb Cu,PSS-Gr/Cu CoIn this experiment,Pt Cu,Pd Cu and Co Cu bimetallic material were synthesized and deposited on functionalized graphene?PSS-Gr?to form PSS-Gr/Pt Cu,PSS-Gr/Pd Cu,PSS-Gr/Cu Co nanocomposite respectively.The PSS-Gr/Pt Cu,PSS-Gr/Pd Cu,PSS-Gr/Cu Co nanocomposites were characterized by Uv-vis,X-ray diffraction?XRD?,energy dispersion spectrometer?EDS?,transmission electron microscopy?TEM?,scanning electron microscopy?SEM?and so on.The three nanocomposites all showed high peroxidase activity,the hydrogen peroxide sensor and the glucose sensor also had high sensitivity and a wide linear range,and realized the detection of glucose in the serum of the actual sample,and the result was accurate.As a result of the bimetal synergy,synthesis of bimetallic nanomaterials exhibit higher peroxidase activity,especially the PSS-Gr/Co Cu,the nanometer material is composed of non-noble metal,but it shows similar properties to precious metals,it certainly will greatly reduce the cost of nano enzyme and for the development of low-cost non-noble metal nano enzyme sensor provides reference.2.Detection of Bisphenol A and melamine based on the oxidase-like catalytic activity of PSS-Gr/Pt Cu,PSS-Gr/Pb CuThis experiment for PSS-Gr/Pt Cu and PSS-Gr/Pd Cu oxidase properties,Under optimized conditions,both PSS-Gr/Pt Cu and PSS-Gr/Pb Cu showed excellent oxidase properties.Based on the oxidase-like catalytic activity of PSS-Gr/Pt Cu a new colorimetric approach for Bisphenol A detection was proposed with the linear range catalytic activity of PSS-Gr/Pd Cu a new colorimetric approach for melamine limit of 6.0×10^-5 M.In addition,the content of melamine in milk was tested and the results were satisfactory.The composites of PSS-Gr/Pt Cu and PSS-Gr/Pb Cu with doped noble metals not only have excellent peroxidase properties,but also have oxidase properties.The dual enzyme activity makes these two nanocomposites have a broader application prospect.3.Based on the peroxidase-like catalytic activity of PSS-Gr/Pt Cu combine with molecular imprinting for detection of puerarin with high selectivityIn order to improve the selectivity of nano enzyme in analysis detection,Based on the peroxidase-like catalytic activity of PSS-Gr/Pt Cu combined with molecular imprinting technology,in which on the surface of composite materials form a molecularly imprinted membrane with target molecules puerarin hole to formed the MIP@PSS-Gr/Pt Cu compound.under the optimal conditions,based on the PSS-Gr/Pt Cu peroxidase properties and specific identification of molecular imprinting technique a selective colorimetric sensor was constructed,the visual selective detection of puerarin which is neither oxidizing substance nor reducing substance is realized.Under optimized conditions,the detection of puerarin with the only realized the visualization detection of the specificity of the puerarin and expanded the application of nano enzyme and provides a reference for more analysis sensor of nano enzyme.4.Based on the oxidase-like catalytic activity of PSS-Gr/Pt Cu combine with lanthanide coordination polymer for detection of Hg²⁺with high selectivityIn this experiment,based on the PSS-Gr/Pt Cu oxidase properties combined with lanthanide coordination polymers,in which on the surface of PSS-Gr/Pt Cu formed the AMP-Tb network structure to formed AMP-Tb@PSS-Gr/Pt Cu compounds.Due PSS-Gr/Pt Cu oxidase properties realized the rapid selective visualization detection of application of metal coordination polymer has greatly improved the recognition ability of the sensor,realized the selective detection of the target object and provided the idea for expanding the application scope of nano enzyme.