Electrochemical Detection Of Transgenic Insect-resistant BT Protein Based On Hydroxyapatite Modified Electrode

With the continuous development of genetically modified technology,the issue of safety of genetically modified organisms has increasingly become a hot issue in the international community,and the rapid detection of genetically modified products has become an urgent issue to be solved.On one hand,the electrochemical analysis method has the characteristics of fast,sensitive,convenient and detecting transient,so it may meet the needs of rapid detection of genetically modified products.Therefore,the development of chemically modified electrodes to improve the electrochemical detecting performance of genetically modified crops/food has great application prospects.On the other hand,hydroxyapatite(HA or HAp,chemical formula:Ca₁₀（PO₄）₆（OH）₂)is one of the main components of animals’hard tissues.It has excellent biocompatibility and biological activity,with multiple adsorption sites and strong adhesion capability,which can provide good micro-environment for protein immobilization and electron transmission.Currently,HAp material has been widely applied in the electrochemical sensing field owing to its unique crystalline structure.Based on these backgrounds mentioned above,HAp with unique crystalline structure was prepared through ion exchange membrane assisted biomineralization,and fabricated to HAp modified carbon paste electrode（HAp-CPE）for the detection of genetically modified Bt protein in this paper.The main contents are listed as follows:1.HAp crystal was prepared by ion exchange membrane assisted biomineralization,and the influences of synthesis conditions（such as pH,calcium ion concentration）on its crystal structure and micro-morphology were identified by X-ray diffraction（XRD）and scanning electron microscopy（SEM）characterization.Then the electrochemical sensing properties of HAp-CPE under different synthetic conditions for the targeted Cry1Ab/Ac protein（a typical biomarker in transgenic rice）were studied in detail.Consequently,the electrochemical testing conditions including HAp materials selection,HAp loading in the modified electrode,supporting electrolyte,sweep-peak current relationship and concentration gradient testing were optimized to improve the electrochemical sensing performance of the modified electrode.2.The HAp@SiO₂ composite microspheres with three-dimensional tunnel structure were synthesized by introducing classical St?ber method into the proposed ion exchange membrane assisted biomineralization system.The crystalline structures,surficial functional groups,and morphologies were characterized by X-ray diffraction（XRD）,Raman spectroscopy（Raman）and transmission electron microscopy（TEM）,respectively.Then the chemically modified electrode was constructed by the as-prepared composite material and applied for sensitive detection of genetically modified Bt protein Cry1Ab/Ac.At the meanwhile,the electrochemical detection conditions were optimized,including HAp materials selection,HAp loading in modified electrode,supporting electrolyte,sweep-peak current relationship and concentration gradient testing,in order to improve the electrochemical sensing capabilities towards the target protein.