Photonic Crystal Sensing Technology For Rapid Detection Of Biotoxin In Food

Objective:This study is based on photonic crystal sensing materials,using patulin aptamers and sulfhydryl oligonucleotide sequences as identification elements,respectively,to establish ultra-sensitive sensing and detection technologies for patulin and ricin,and realize Label-free ultra-sensitive detection of patulin and ricin.Method:key to optimizing the experimental conditions using orthogonal synthesis of monodisperse uniform particle size silica（SiO₂）microspheres,the modified gold nanoparticles（Au NPs）of silica microspheres（SiO₂）by self-assembly method of vertically precipitation Stackable polystyrene 24-well plates,prepared opal photonic crystals（PC）,and the photonic crystals are modified with patulin aptamer or oligonucleotide sequence H1 to realize the distingush of patulin or ricin by the sensing material.By investigating the response performance of the prepared sensing material to the target under different experimental conditions,the incubation conditions of the identification element and the SiO₂-Au NPs photonic crystal were optimized.Using a transmission electron microscope（TEM）,scanning electron microscopy（SEM）and atomic force microscopy（AFM）detection material for synthesis and characterization,photonic crystals and sensing materials before and after the detection of the target,and to explore the response mechanism preliminarily.The specificity and accuracy of the sensing materials were investigated through specificity experiments and standard addition and recovery experiments.And compare with the national standard method to verify the reliability of the sensing material.Result:1.First,the orthogonal design was used to optimize the key experimental conditions,and through the hydrolysis and condensation polymerization of ethyl orthosilicate under the catalyzed conditions of ammonia water to form silicon dioxide（SiO₂）microspheres with a controllable particle size,and set different rotation speeds to screen out 230 nm dioxide Silicon microspheres,using3-aminopropyltriethoxysilane（APTES）as the silane coupling agent to aminate the microspheres.Under alkaline conditions（NaOH）,using THPC as a reducing agent,HAu Cl₄is reduced to gold nanoparticles（Au NPs）.A suspension of SiO₂-Au NPs microspheres was prepared by the N-Au interaction between amino groups and Au NPs,and then the suspension was self-assembled by vertical sedimentation to prepare photonic crystal（PC）sensing materials.2.Using the sulfhydryl patulin aptamer as the identification element,the Apt-PCs photonic crystal sensing material was prepared,and the ultra-sensitive and label-free detection technology for patulin was established.Under optimum conditions,the diffraction peak intensity of the sensing material with the increasing development of penicillin concentration decreased,the number of the diffraction peak intensity and the amount of change of the patulin concentration have a linear relationship,and the linear range is from10fg/m L to 50（?）g/m L,the lowest detection limit is 0.6180fg/m L.The established detection technology was used to carry out standard addition and recovery experiments on commercially available apple juice and orange juice,and the standard addition recovery rate was between 88.35%～112.75%.Using known traditional detection methods,chromatography-mass spectrometry（LC-MS）,sampling and actual sample detection are used to verify the accuracy of the method and perform statistical analysis.This method has the characteristics of high detection sensitivity,simple sample preparation,and high cost-effectiveness.3.Using oligonucleotide sequences to modify SiO₂-Au NPs photonic crystals to prepare H1-PCs sensing materials and establish an ultra-sensitive detection technology for trace ricin.Under optimum conditions,the diffraction peak intensity as ricin sensing material will increase the concentration decreases,and the number of the diffraction peak intensity variation of ricin concentration have a linear relationship.The detection range is1fg/m L to 1（?）g/m L,the detection limit is 0.2089fg/m L.By adding recovery experiments found that the water and skim milk,recoveries between 89.30%～99.38%.Compared with the ELISA method national standard method,the results show that this method has high sensitivity,good accuracy.Conclusion:This study established a label-free rapid detection method based on photonic crystal sensing materials,which further expanded the application fields of photonic crystals.A systematic and complete methodological comparison was carried out through statistical analysis and comparison,which showed that the technology is simple to operate and the preparation process is simple.In addition,the photonic crystal material can not only modify nucleic acid aptamers and oligonucleotide sequences,but also try to modify recognition elements such as antibodies and receptors,so as to further expand the application range of the sensor material.The fields of disease diagnosis and environmental monitoring have broad application prospects...