Self-Powered Biosensor Based On Enzyme-Phosphate Hybrid Material

The organic-inorganic hybrid materials formed using biomolecules and nanomaterials not only ensure the specificity and activity of the enzyme,but also improve the stability of the enzyme,which to some extent solves the problem of easy inactivation of the enzyme.Inorganic materials can change the quaternary structure of enzymes,exposing more active sites,and combine with the catalytic properties of inorganic materials themselves,they play a unique synergistic role,making organic-inorganic hybrid materials have great application prospects in fields such as biosensors.At present,small size and high-power density is an important research direction of self-powered biosensors.In order to improve the power density of self-powered biosensors,this paper will use organic-inorganic hybrid material to build self-powered biosensors,and explore its effect on power density.In this paper,enzyme-M₃（PO₄）₂/CC)organic-inorganic hybrid nanomaterials are grown in situ on carbon cloth by liquid phase chemical coprecipitation at room temperature,using enzymes（glucose oxidase or laccase）as organic components,and phosphates（Cu₃（PO₄）₂,Co₃（PO₄）₂,Ni₃（PO₄）₂）as inorganic components.The effects of different reactant concentrations,reaction methods,and reaction time on the morphology and properties of materials are investigated,and the growth mechanism of hybrid materials is preliminarily explored.Three self-powered biosensors（SPB）（enzyme-Cu₃（PO₄）₂/CC,enzyme-Co₃（PO₄）₂/CC,and enzyme-Ni₃（PO₄）₂/CC）are constructed using the prepared GOx-M₃（PO₄）₂/CC as biological anode and Lac-M₃（PO₄）₂/CC as biological cathode,The full text is divided into three chapters,and the main research contents are as follows:（1）Using enzymes（GOx or Lac）as organic components and copper phosphate（Cu₃（PO₄）₂）as inorganic components,the enzyme-Cu₃（PO₄）₂ hybrid material is in-situ grown on carbon cloth by liquid phase chemical coprecipitation at room temperature.The micromorphology,crystal structure,and chemical composition of the prepared hybrid material are analyzed by various characterization techniques such as SEM,TEM,EDS,XRD,FT-IR,and UV-vis,and the growth mechanism of enzyme-Cu₃（PO₄）₂/CC was preliminarily explored.A self-powered biosensor is constructed using the prepared glucose oxidase copper phosphate/carbon cloth（GOx-Cu₃（PO₄）₂/CC）as a biological anode and laccase copper phosphate/carbon cloth（Lac-Cu₃（PO₄）₂/CC）as a biological cathode.The electrochemical performance is analyzed by an electrochemical workstation.The constructed SPB is successfully used for glucose detection with a power density of 547.97 μW·cm^-3,linear detection range 0.1-0.5 mM,minimum detection limit 2.05 μM。The three-dimensional flower like structure of enzyme-Cu₃（PO₄）₂ increases the specific surface area,potentially exposing more enzyme active sites,and making it easier to contact the substrate to be tested.This improves the sensing performance,stability,and power density of the self-powered biosensor.At the same time,it has been proved that the organic-inorganic hybrid material enzyme-Cu₃（PO₄）₂ can improve the power density of self-powered biosensor.（2）In order to further explore the influence of different metal ions on the power density in organic-inorganic hybrid materials,select cobalt ions(Co²⁺)and nickel ions(Ni²⁺)that have catalytic effects on glucose,and use their phosphates as inorganic components,and enzymes（GOx and Lac）were used as organic components to prepare enzyme-Co₃（PO₄）₂/CC and enzyme-Ni₃（PO₄）₂/CC hybrid materials.The effects of different reaction times and reactant concentrations on the morphology of the hybrid materials are also investigated.The micromorphology,crystal structure,and chemical composition of the prepared hybrid materials were analyzed using various characterization techniques such as SEM,TEM,EDS,XRD,FT-IR,and UV-vis.The electrochemical performance of the enzyme-Co₃（PO₄）₂ SPB and the enzyme-Ni₃（PO₄）₂/CC SPB are analyzed using an electrochemical workstation.The developed SPB has also been successfully used for the detection of glucose.The enzyme-CO₃（PO₄）₂ SPB’s power density is 596.21μW·cm^-3,linear detection range 0.01-2.0 mM,minimum detection limit 1.11 μM。The enzyme-Ni₃（PO₄）₂/CC SPB’s power density is 771 μW·cm^-3,linear detection range 0.025-0.6 mM,minimum detection limit 0.902 μM。Comparing the three types of SPBs,the largest increase in power density of the enzyme-Ni₃（PO₄）₂/CC SPB may be due to the catalytic effect of Cu²⁺on glucose requires a large amount of OH-to participate under alkaline conditions,while the SPBs constructed under acidic conditions in this paper.Co²⁺ and Ni²⁺will generate Co⁴⁺and Ni³⁺ that have catalytic effect on glucose in the reaction process,but the process of generating Ni³⁺ is simpler,so the power density of SPB constructed by enzyme-Ni₃（PO₄）₂ hybrid material increases the most.The constructed enzyme-Ni₃（PO₄）₂/CC SPB is miniaturized to reduce its volume.SPB constructed using enzyme-M₃（PO₄）₂/CC has broad application prospects in the fields of biomedicine,bio-catalysis,food detection,and medical detection.